Wikipedia:Reference desk/Science

July 26

Lettuce in the dishwasher

Why is it that when I don't completely rinse off all of the scraps of lettuce from a utensil, or plate, or anything, it won't come off in the dishwasher but will easily come off by just rinsing it under the sink? 68.231.151.161 02:10, 26 July 2007 (UTC)

In the sink, a very clever intelligence is controlling the washing action and the lettuce-loaded water goes down the drain. In the dishwasher, the lettuce-loaded water just goes round-and-round again, potentially redepositing the lettuce elsewhere. (The water does go through a built-in garbage grinder, but it may not handle 100% of the flow and the grinder may not be 100% effective.) Also, depending on how you load your dishwasher, there may be lots of "shadows" that aren't effectively washed by the water blasts, forming sorts of hydraulic Lagrangian points for food debris.

Atlant 16:00, 26 July 2007 (UTC)

Hah, nice one I like it =) --froth^t 02:16, 27 July 2007 (UTC)

Identify this insect

What kind of bug is this?

http://www.flickr.com/photo_zoom.gne?id=900187829&size=o

Foobody 02:33, 26 July 2007 (UTC) (edited to add sig)

Well, the image is somewhat blurry and small, but they look like wood lice to me (or, more generically, the woodlouse article). -- MarcoTolo 03:47, 26 July 2007 (UTC)

The skin beetles or Dermestidae. The picture is from german article - Gemeiner Speckkäfer.--Stone 12:32, 26 July 2007 (UTC)

Looks like a carpet bug sometimes known as 'wooly bears'?213.249.237.190 13:04, 26 July 2007 (UTC)

I agree with Stone that the "bugs" are probably the larvae of a Dermestid. They look like one of the species in the genus Anthrenus, commonly called Carpet Beetles. They can be serious problems in homes or museums because they can severely damage textiles and other organic substances. --Eriastrum 16:11, 26 July 2007 (UTC)

what percentage of bone is carbon?

Hi I'd love to be able to find out what percentage of bone is carbon ? I'm interested in calculating how much greenhouse gases are "fixed" into bone when farm animals grow. Cheers 61.9.137.86 05:41, 26 July 2007 (UTC)DaveBeggs

Farm animals don't get their carbon from greenhouse gases so "0". But water is the biggest greenhouse gas and animals are about 70% water I believe. --Tbeatty 06:26, 26 July 2007 (UTC)

Yeah um, animals get their carbon from food, not from air. Only plants fix carbon from the atmosphere. —Keenan Pepper 10:22, 26 July 2007 (UTC)

Cows get carbon from grass, grass gets carbon from the air - so although the cow doesn't fix carbon from the air, it does incorporate atmospheric carbon through the intermediary of grass. DuncanHill 10:45, 26 July 2007 (UTC)

The problem is that it's a zero sum game. When the animal dies, the bone's organic content is metabolised by bacteria, etc - only the calcium content remains. So burying bones isn't really locking away much (if any) carbon. I'm pretty sure that no useful dent in global warming could be made in this manner. Having animals eat carbon-laden plants then 'sequestering' the animal corpses is a lot worse than just sequestering the plants directly. Note particularly that animals produce methane as well as CO2 - and methane is an even nastier greenhouse gas than CO2. Having fewer domesticated animals in the first place would go some way reducing the greenhouse effect. SteveBaker 11:49, 26 July 2007 (UTC)

I remember seeing some little blurb in a NYT article, where some biologist calculated the net effect on global warming the increasing obesity in the United States was causing. By storing away carbon in the form of fat instead of burning it off as carbon dioxide, a continuously fattening populace actually slows the rate of temperature increase. Unfortunately, he calculated the effect to be on the order of billionths or trillionths of the total temperature change. We clearly aren't eating enough. 151.152.101.44 19:39, 26 July 2007 (UTC)

Cute. But of course the fatter we are, the more gasoline our cars use to haul us around -- and the more likely we are to drive rather than walk or bike. I'd expect that this effect outweighs the other one by quite a few orders of magnitude. --Trovatore 19:54, 26 July 2007 (UTC)

This claim that America's increasing waistlines were causing us to burn some outrageous amount of extra gasoline was in the press recently - the debate came up at work and I showed that it was utterly negligable. Filling your gas tank only half full and stopping off for gas twice as often will probably save you the weight of 10 gallons of gas (60lbs) on the average - nobody is telling us to do that! Toss out your 25lb spare wheel, carry a AAA card instead. Unbolt and remove the passenger seat when there's nobody sitting in it and you've saved another 25lbs. We don't consider doing these things because their effect is rather negligable compared (say) to driving a 1,300lb Mini instead of a 8,000lb SUV. 02:06, 27 July 2007 (UTC)

By the way, I notice that no one has even attempted to answer the literal original question. What percentage of bone is carbon? By the way, I doubt Steve's claim that the carbon in bone is metabolized by bacteria -- my guess is that it's in the form of calcium carbonate or some such, not counting the marrow as part of the bone, of course. --Trovatore 20:46, 26 July 2007 (UTC)

I'm working on it. It's surprisingly difficult to find! Flyguy649 ^talk _contribs 21:05, 26 July 2007 (UTC)

From this ref: Bones are 20% water, and 75% of the dry weight is organic matter, and while there is some carbonate in the inorganic, we'll ignore it. Proteins are ~45% carbon by mass. So roughly speaking, wet bone is 25% carbon. Flyguy649 ^talk _contribs 22:27, 26 July 2007 (UTC)

Bone is about 50% protein - mostly collagen. GB 22:28, 26 July 2007 (UTC)

Charge buildup through friction with air

Friction between materials can cause the build up of a charge (triboelectric effect), but are there materials that build up a charge when air (wind) rushes past them? DirkvdM 05:42, 26 July 2007 (UTC)

I suppose that's how thunderstorms are made. Bo Jacoby 06:59, 26 July 2007 (UTC).

You mean lightning, yeah, I thought about that too, but that seems to be a different effect (although it doesn't have to be the same effect). Anyway, I'm looking for a solid material, at least something one can build something out of, so to say. DirkvdM 07:48, 26 July 2007 (UTC)

What is your project? A wind-driven electrostatic power plant? That's a great idea. Bo Jacoby 08:01, 26 July 2007 (UTC).

Unless you happen to live downwind of the thing and are concerned about lightning damage! But one assumes the amount of energy you could extract this way would be small - so my concern is probably more theoretical than real. SteveBaker 11:41, 26 July 2007 (UTC)

I seem to remember some concern over using dust blowers on static sensitive circuitry due to the fact that the air got charged up, but I cant remember where I saw it. If the air got charged, then presumably an insulated nozzle would get charged the opposite way?--SpectrumAnalyser 12:46, 26 July 2007 (UTC)

I have a faint memory of reading in a book or seeing in a documentary about building skyscrapers that static electricity buildup is a problem due to wind blowing past the building and the electrical potential between the air at the top of the building and the air at the bottom of the building. It led to an experiment I tried - putting an antenna on top of a 13-floor building and another in the ground and measuring voltage/amperage between the two (connected by thickly insulated wiring. The amperage was negligible, but the voltage was measurable at only 13 floors. I wouldn't be surprised if it was much higher at 100 floors. -- Kainaw^(what?) 19:07, 26 July 2007 (UTC)

Well that's promising. A building isn't designed to build up a charge - it might even be designed not to. So if it already works there, then what if the building were coated in the right sort of material? Btw, I want a charge in the material, not in the air, but I suppose that comes down to the same thing. DirkvdM 19:14, 26 July 2007 (UTC)

SpectrumAnalyser, is or the air and the circuitry that creates the charge? Instinctively I'd say plastic sounds like a good material. DirkvdM 19:14, 26 July 2007 (UTC)

I presumed it the friction between the air and the nozzle that charges them both when I read the advice, but my memory is very vague --SpectrumAnalyser 22:55, 26 July 2007 (UTC)

Steve, why do you say the charge-buildup would be small? The surface of a windmill isn't too big, yet it can generate several MW. Imagine this stuff on the roof of a factory. That's quite a surface and would have a great potential for slowing down the wind, which is basically the source of wind-energy (and it would be right where a lot of energy is needed). DirkvdM 19:14, 26 July 2007 (UTC)

You are all making the common error of confusing voltage and current. Sure, you can build up enormous voltages - but you aren't extracting much power because it's just a static charge. Sure, you'll get an occasional impressive spark - but the total current flowing (and therefore the total energy extracted from the wind) is tiny compared to what a windmill could produce. Static-sensitive circuitry suffers horribly from a huge voltage - even if the current flow it tiny and brief - but you can't build useful powerstations that run on static electricity. SteveBaker 01:53, 27 July 2007 (UTC)

Wait a minute, Steve, I distinctly remember hearing about a guy who had a house powered by static electricity. To get the living room lights to go on, he'd shuffle his feet on the carpet. To operate his television, he'd pet his cat. In fact, I think his name was Steve. Oh, wait, it was Steven Wright. "Never mind." —Steve Summit (talk) 02:56, 27 July 2007 (UTC)

Sorry, but Wikipedia cannot offer advice on how to create machines to use in your diabolical plans to take over the world. Please consult with your doctor. Thanks. kmccoy (talk) 23:09, 26 July 2007 (UTC)

Glad you brought that up. I'm not asking for the design of infernal machines or such. :) I just want to know what material would build up a charge when air rushes past it. And I'm quite serious by the way. I really want to know this. DirkvdM 06:34, 27 July 2007 (UTC)

Iron ore

Why iron -ore deposits on hill tops occur only in sedimentary form ?

Most of the time sedimentary, but pyrite for example is not sedimentary but created by hot water transport.--Stone 13:01, 26 July 2007 (UTC)

We have quite a good article at Iron ore which discusses some of the different ores and their modes of formation. DuncanHill 16:47, 26 July 2007 (UTC)

Exotic or Negative Mass to reduce net mass?

Picture of the object

Assuming one could create and use exotic matter or negative mass, would it be possible to reduce the "net mass" of an object made of both mass and exotic mass (as shown in the picture)? If so, would that not mean that the net mass of an object could be reduced below that of a photon (or all together negate the effective mass of the object) so that higher-than-lightspeed-travel would be possible? --Demonesque 07:30, 26 July 2007 (UTC)

Yes, assuming the impossible, anything is possible. Bo Jacoby 07:55, 26 July 2007 (UTC).

Thanks, so very, very, extremely helpful. I realize that my question is speculative, since exotic matter itself is speculative, but what I am trying to find out is whether or not the two bodies would negate each other's mass as described or if it would be no different than two objects of different types of mass (or in other words, if the exotic mass would just be adding to the mass of the object.) --Demonesque 14:22, 26 July 2007 (UTC)

Seriously, the answer is yes or no depending entirely on the assumed properties of the exotic matter and how it interacts with normal matter. As we have no examples of exotic matter, we have no constraints. Hence you are free to assume it to be true if you want to. That said, I think it would be far less weird if exotic matter had a positive inertial mass and only a negative gravitational mass. My opinion on what is asthetically pleasing would exclude your scenario. Dragons flight 14:43, 26 July 2007 (UTC)

I'd agree, looking at the articles, only negative gravitational mass appears to have been postulated, negative inertial mass appears to be paradoxical in its very concept, that applying a force in one direction would provide acceleration in the other, I cant see how that could possibly fit in with conservation of energy and momentum. Philc 14:28, 27 July 2007 (UTC)

It wouldn't work. From my knowledge of special relativity, anything with a nonzero real mass must move below the speed of light in order to have a real amount of energy. If you can have nonreal amounts, it can be done with just matter of positive mass. What you're looking for involves imaginary mass. You also can't just package something with positive mass and something with negative mass to make it add to zero and go the speed of light. Each individual particle has to be able to travel that speed. By the way, I'm using mass to mean absolute mass, and energy to mean relative mass. — Daniel 23:38, 27 July 2007 (UTC)

automobile steering

after an automobile initiates a turn ,its steering automatically aligns or comes back to its initial position even without our effort.how does this happen? 210.212.228.8 07:58, 26 July 2007 (UTC)

see caster angle. It is actually more complicated than that, but only at a level way more complex than wiki can stand. Greglocock 08:33, 26 July 2007 (UTC)

A couple of ways to do it.

Caster: First, by tilting the steering axis, it can be set up so that the contact point of the tire with the ground is actually behind the steering axis, rather than right on it as when the steering axis would be vertical through the centerline of the hub. Since there is some drag, the contact of tire with road will naturally attempt to place itself as far back from the steering axis as possible. (look at the steering axis of a bicycle for example; i.e., the headtube, the bearings right below the handlebars that the fork pivots in. They're not vertical, they're tilted so that the line through them hits the floor forward of where the tire hits the floor. The curve in the bicycle's forks that moves the wheel forward is to reduce the self straightening action of this. The further back the contact point is from the axis, the more "relaxed" the steering is, wanting to just stay straight. the closer the contact point is to the axis, the more twitchy the steering becomes. If the contact point is moved forward of the steering axis, the steering is unstable, it has to be constantly prevented from deviating from straight.). Same reason "casters" on furniture or suitcases or grocery carts get called that; in that case, the steering axis that the whole thing swivels on is vertical, but the whole wheel is offset so that the steering axis doesn't go through its center; when you push the cart or whatever, the wheels naturally lines up so that it's straight back from the steering axis.

That all works, as you may have noticed, on wheels that are not powered, i.e. not front wheel drive. You can imagine that if the wheel is pulling the car forward, the tendency for the wheel to be pulled straight back from the steering axis is reduced. So, another way to do it is having it set up so that when the wheel is turned, it raises that corner of the car up a tiny bit; the weight of the car will then tend to pull it down, and keep the wheels straight. Luckily, this is accomplished by... tilting the steering axis.

The other thing that is partially related is toe-in. The front wheels are sort of pigeon toed, i.e. the fronts are closer together than the rears. If you fiddle with that for a while, you see that if the car is turned in one direction, that makes one wheel run straighter, while the other wheel is more "crooked". This generates a force that tends to push the car back to where both wheels are equally crooked, in opposite directions. Again, this doesn't work for front wheel drive, where they are often toed out.

So, combining all these things to the proper amount depends on fwd vs rwd, the weight of the car, and a dozen other things. Gzuckier 19:35, 26 July 2007 (UTC)

Tilting Immersion blenders

While mixing some food with an immersion blender, I noticed that whenever the device was tilted and spinning, there was a powerful force trying to bring it back to vertical. I thought at first that it was some kind of gyroscope effect, as it only happened when the blades were spinning, but found that on further investigation, the blender tried to return to vertical even when started at an angle. Any ideas what could have been causing this effect? (If it helps, I was blending tinned tomatoes) Laïka 13:07, 26 July 2007 (UTC)

Does it do this when not placed in the food ? I'm thinking you have it at an angle, partly in the food and partly out, causing it to pull down in the food where you have contact, which would tend to make it go vertical. StuRat 15:17, 26 July 2007 (UTC)

It does only happen in the food, but the bowl is much deeper than the height of the blades; the tomato covers the whole apparatus even when at an angle. Laïka 15:42, 26 July 2007 (UTC)

Is it not just pressure differences? The spinning blades accelerate the food being blended so that it exits the blender through the slits in the side of the round head. This lowers the pressure in the round head, so the higher pressure in the rest of the bowl pushes the food into blades; at the same time, the lower pressure below the head compared to above means the head gets pushed down. People often think of this as the lower pressure 'pulling' the round head down and the food up into the blades. The head of the blender gets 'pulled' towards the position of vertically standing up on the bottom of the bowl; if you put it in that position, you'll find it hard to lift up as well as tilt. Thinking about it, I hope you can see that tilting the blender leads to it 'pulling' more strongly one way than the other; I hope you can see it, because I can't think of a good way to describe it over the internet! Skittle 21:05, 26 July 2007 (UTC)

That makes sense; I hadn't thought about the pressure differences caused by the blades. Thanks! Laïka 21:40, 26 July 2007 (UTC)

Nano tubes synthesis

Is it possible to synthesise nanotubes of CuS using dimethyl glyoxime as a capping agent?If yes what are the reagents to be used? Its a project requirement.

This is the first I hear of anything other than carbon nanotubes. anyway - Dr N S Xu of Zhongshan University grew copper sulfide nanowire by treating copper foil with hydrogen sulfide and oxygen mixture for 10 hours at room temperature. No solutions were involved.[1]. GB 11:42, 27 July 2007 (UTC)

Future of Key Boards

In the future, will the standard keyboard be replaced by another method of communicating?-—Preceding unsigned comment added by WonderFran (talk • contribs)

Probably, but the Reference desk, despite what you may have been told, hasn't had a working crystal ball since the TimeQuake of 2005. - CHAIRBOY (☎) 15:59, 26 July 2007 (UTC)

Although not terribly new (patented in 1936), there's the Dvorak Simplified Keyboard, which a lot of people are starting to use instead of the standard QWERTY keyboard. -- JSBillings 16:37, 26 July 2007 (UTC)

I've tried to use the Dvorak, but I've had difficulty finding a dumbed-down howto for getting the OS (Fedora in my case) to accept a Dvorak keyboard for input. -- Kainaw^(what?) 16:57, 26 July 2007 (UTC)

There's a line you can put in /etc/sysconfig/keyboard that'll tell it to use dvorak. I think it's something like KEYTABLE="dvorak" -- JSBillings 17:02, 26 July 2007 (UTC)

"A lot" is not that many people, no doubt less than 1% of computer markets worldwide (remember that OS X, which you can see in practically any coffee shop, is still only around 5% of the market share!). It's not going to become truly popular anytime soon, because its purported advantages are not enough to overcome the disadvantages of trying to change the input devices for an entire technology. --24.147.86.187 21:54, 26 July 2007 (UTC)

Ah, that's for a different reason. People take laptops to coffee shops to show off and be snooty- thus OS X --froth^t 02:14, 27 July 2007 (UTC)

This guy who had equipped his bicycle with pc hardware, satellite uplink, etc. way back when and roamed the US writing columns about it for a living had set up eight switches, four for the fingers on each hand, so that he could type while biking, in raw Ascii 8 bit digital. Now that is cool. Gzuckier 19:39, 26 July 2007 (UTC)

That sounds like a great way to have a biking accident... --24.147.86.187 21:54, 26 July 2007 (UTC)

The odds are the standard keyboard will not. It allows for precise input of written alphabetic languages at relatively high speeds (with practice, obviously). There is no serious competitor to this sort of functionality at the moment. Voice-to-text technology might increase its ability to replace it but I doubt it will ever be anything more than a supplementary technology — even assuming that it was made far more precise and generalizable than it currently is, strictly speaking you often don't want to have to speak to write things down. (If you think people talking on cell phones is annoying, imagine how it would be if everyone was dictating their e-mails!)

That being said, here are two futuristic speculations:

• What if alphabetic languages become economically less important? Imagine that a language like Chinese, which is not alphabetic, became a prerequisite for global commerce and communication? Keyboards are notoriously more difficult for non-alphabetic languages than for alphabetic ones, so I could imagine some other technology more suited to non-alphabetic languages becoming popular and supplanting the traditional keyboard.
• What if we had a way to directly receive signals from the brain and transfer them into writing? You could skip the hands altogether as a way of translating thought language into written language. Is this ever going to be possible? Probably — if the brain can tell the fingers how to use a keyboard, then there is likely going to be some way to intercept that same sort of set of instructions. The real question, as I see it, as to whether it would become a realistic and popular technology is whether or not it could do this easily and non-invasively — I don't think most people are going to want to have things embedded in their bodies just to take care of the chore of not typing (some no doubt would, though — aside from cyberpunk fetish geeks, I could imagine parapalegics, sufferers from repetitive strain injuries, etc. finding this sort of technology useful even if it is invasive). Anyway, advances towards this sort of thing are going pretty well at the moment, I believe, though anything rivaling the precision/speed of a keyboard is still some time off, I think.

Just some food for thought... --24.147.86.187 21:54, 26 July 2007 (UTC)

Speech is handy in niche markets - phone response systems, hands-off stuff in cars, that kinds of thing. The human voice has some advantages and some disadvantages - firstly, it works at a distance and it works around corners. It's a broadcast mechanism - one person talks and everyone in the room can hear. It's very error-prone (we mis-speak and mis-hear all the time) - but that doesn't matter too much in most conversation because the person you're talking to can generally ask questions to clarify. These are all great things in some sorts of situation - but they are nothing short of disasterous when interfacing to computers - every computer in the room might respond to your command to copy the file named "reformat" onto the disk - but then the computer you were actually talking to might hear this as a command to "reformat the disk". Humans know that eye contact contains information about who within a conversation is being addressed and who is merely listening in. Offices are annoyingly noisy places - speech input will make that vastly worse. You want to work on your computer while watching TV or listening to music? Dangerous! Who knows what some actor on TV is telling their computer and getting picked up on your microphone? It's notoriously difficult to do something as conveying your email address by voice - mine used to be sjbaker1@airmail.net (not anymore) - the number of times I had to tell people "no that's the digit '1', not the word 'one'" - and correct people who thought 'airmail' was 'air male' or something. Just try reading a C++ program source to people:

  #include <stdio.h>
  #define pythag_rule(x,y) sqrt((x)*(x)+(y)*(y))
  void main ( int argc, char **argv )
  {
    const char helloWorld[] = "Hello World.\n" ;

Reading a million lines of that stuff to the computer ACCURATELY - where a missing semicolon can take you a week to track down...I don't think so!

Keyboards are a pain - but there is very little sign of them ever going away. SteveBaker 01:43, 27 July 2007 (UTC)

There's a bit of a fallacy in your argument, though: "Today's computer languages all require utterly precise placement of semicolons and other punctuation, ergo keyboards will never go away for programming." —Steve Summit (talk) 02:34, 27 July 2007 (UTC)

Hmmm - natural language programming...yeah - good luck with that one! So what is "one plus two times three"? Seven? Nine? Maybe I'd better says "one plus open bracket two times three close bracket"...but before you can blink, math and control structure gets so phreaking complicated that you just can't turn it into spoken words...it's just too complicated. To pick the line of code I just typed: "glVertex2f((float)x_cen+rad*(float)sin((double)val),(float)y_cen+rad*(float)cos((double)val));" - how the heck are you going to express that in natural language? The closest we ever got to that was COBOL - which is without doubt one of the nastiest programming languages ever to hit the big-time. It only became remotely usable when they finally dropped: "ADD 1 TO 2 GIVING X  ; MULTIPLY 3 BY X GIVING Y" and allowed "COMPUTE Y = (1+2)*3" but the whole point of using a programming language is to avoid the horrible pitfalls of natural language and to wind up with something concise and unambiguous. SteveBaker 17:04, 27 July 2007 (UTC)

Now where did I say anything about natural-language programming? I wasn't even thinking of natural-language programming!

You, I think, are still thinking too narrowly (and perhaps even circularly). If you assume programming has to be done with keyboards, then of course all you're going to think about are computer languages that have evolved around the assumption of typing them in via keyboards, so of course it's going to be difficult to think about abandoning keyboards while those languages are still in use.

Me, I was imagining that once direct-brain man-machine interfaces become widespread (and, yes, I do assume this will happen), we'll begin devising some completely different computer languages optimized around the strengths and weaknesses of that interface. I don't imagine that a direct-brain interface will be perfect; in fact I'm reasonably sure it'll be lousy at handling conventional human languages, or traditional computer languages, or images, or indeed anything that we're used to doing with our five regular senses. But if it works well at some bizarre other level, we can invent "languages" that work well at that level. (Though they're likely to be so bizarre that we can't begin to describe them today, until we know what a direct-brain interface "feels like" and can do.)

But this is probably a little too speculative for the Science desk, and we don't seem to have a Science Fiction desk. So I'll stop now.

Steve Summit (talk) 23:27, 27 July 2007 (UTC)

I believe Loglan (admittedly not a natural language) has a way to pronounce parentheses. —Tamfang 03:42, 30 July 2007 (UTC)

Speaking of the computer-controlled-by-speech-on-the-TV issue, I once heard a (possibly apocryphal) story where a kids show host said "hey kids, hold your phone up to the TV if you want to talk to Krusty!", and they played the touch-tones of a 900 (pay) number on the air, which dialed all these kids' phones and made Krusty (or whoever) a bunch of money! --TotoBaggins 14:16, 27 July 2007 (UTC)

Ooohhh! Good one! SteveBaker 17:04, 27 July 2007 (UTC)

Actually, it made me think of the recently suggested flaw in Windows Vista (which is now either patched or soon-to-be patched), where a combination of low security on voice-activated commands and a theoretical piece of speaker-controlling spyware could have every computer in a room formatting its hard drive. Confusing Manifestation 11:54, 28 July 2007 (UTC)

Someone mentioned mind dictation? While mind dictation is not yet possible, mind control in a very limited form is, see [2]. BTW, completely OT but I came across this which I hope is a hoax/spoof [3] Nil Einne 16:17, 28 July 2007 (UTC)

Salmonella odds

So I've always eaten raw eggs -- in mayonaises and various other things -- and I now work in a restaurant that keeps its raw egg mayonaisses and other possibly salmonella-risky things for up to a week. The restaurant's in Italy, so nobody cares. And I'm becoming convinced, because nobody cares, that my squeamishness about leaving raw eggs for a week in the fridge is ridiculous. The question I'm getting at is a) whether Salmonella is still so much of a risk as it was, say ten years ago, and b) whether the eggs I and the restaurant use -- organic eggs that have never seen one of those gigantic chicken coups they show in vegetarian horror propaganda movies -- have any risk at all for salmonella. Oh. And also, what is the risk even for mass-produced eggs? If I were, say, to eat a raw egg every day for a year, is it at all likely that I'd get Salmonella? And what are the odds of Salmonella, if I do get it, causing any sort of permanent damage or death? I did look at the Salmanellosis or whatever article, but it was kind of vague where I was concerned. Thanks, Sasha —Preceding unsigned comment added by 151.28.233.89 (talk • contribs)

I can't vouch for Italy, but in the UK, all poultry is vaccinated against Salmonella (see Egg (food)#Edwina Currie, Salmonella and the UK Lion Mark); indeed a random test of 28,000 eggs, a grand total of 0 eggs had Salmonella. Laïka 21:38, 26 July 2007 (UTC)

The CDC says there are 1.4 million cases of salmonella in the USA each year. Presumably some non-trivial percentage of that is from eating raw eggs, so I'd say at least in this country it's a not-insubstantial risk. Italy is probably similar. --TotoBaggins 14:18, 27 July 2007 (UTC)

Have a look at figure 2, page 3 here. Looks like Salmonella levels in italian flocks are pretty low, though not quite as low as in the UK. This is not medical advice, but unless you are immune-compromised, pregnant, elderly or very young, your chances of Bad Things from eating eggs seem low. Skittle 13:01, 29 July 2007 (UTC)

aids

can someone get effected by aids through licking? —Preceding unsigned comment added by 217.69.178.16 (talk • contribs) 21:44, 26 July 2007

Wikipedia cannot dispense medical advice. Please consult a doctor if you have a question. For purely informational purposes, you should read the article about AIDS -- JSBillings

Licking what? Skin, genitals, an open wound? --24.147.86.187 21:56, 26 July 2007 (UTC)

Deer? Capuchin 07:57, 27 July 2007 (UTC)

Licking, Missouri? The Aids Project of the Ozarks [4] being 49 miles away implies that it might be possible. Edison 17:18, 27 July 2007 (UTC)

July 27

random number generation by the human mind

How does the mind do it? And have there any been any experiments to see just how non random they are? When I rattle off a few they tend to end in a multiple of 3 and they're all decimal numbers from 10-99.. --froth^t 01:51, 27 July 2007 (UTC)

Not exactly a study, but I do know that what humans think of as random often doesn't match with something that's actually random - for example, I recall reading about a professor (of statistics, I assume) who got his class to write down a "random" string of fifty coin tosses either by making it up or by actually flipping the coins, and he could tell which was which by the fact that the real ones often had long strings of either heads or tails (say 5 or 6 in a row), whereas the made-up ones didn't, because we don't think a string of HHHHH in the midst of fifty trials appears "random". Confusing Manifestation 02:23, 27 July 2007 (UTC)

Statisticians often misunderstand what people mean by saying a string like HHHHH doesn't look "random". What they mean (though they don't always know this formally) is not, "this is not possible given that each trial is independent" (which is how statisticians interpret them), but rather "a series of homogenous results is less likely than a series of varied results given that each trial is independent". In that sense the brain of the "common person" is completely correct to see HHHHHH as being less likely to be caused by a random generator than HTHTTHH or something like that. The odds of getting homogenous results from independent trials are far less likely than getting mixed results. (There is an article on this exact question using your exact example: Lola L. Lopes, "Doing the impossible: A note on induction and the experience of randomness," Journal of Experimental Psychology: Learning, Memory and Cognition vol. 8, no. 6 (1982): 626-636.) --24.147.86.187 20:42, 27 July 2007 (UTC)

I concur with Confusing Manifestation.

I suspect that humans are less likely to pick "special" numbers, so the digits 0, 1, 5 and 9 might be underrepresented. Your own experience tends to show this: you tend not to pick 0 as the first digit of a two digit number.

There is a parler trick where one is asked to pick a number from 1 to 50, with the conditions that both digits are odd and they are not the same. Then they are told "your number is 37." It works surprisingly frequently. But I think I understand why: only 8 numbers pass both conditions: 13, 15, 17, 19, 31, 35, 37 and 39. The only one that does not contain a "special" digit is 37.

I do not have a reference to the psychology, but David Blaine performed the trick live on his TV show Street Magic. Baccyak4H (Yak!) 03:04, 27 July 2007 (UTC)

You might be interested in W.A. Wagenaar,"Generation of random sequences by human subjects: a critical survey of the literature" (PDF)., Psychological Bulletin 1972, Vol. 77, No. 1, 65-72. Rockpocket 07:12, 27 July 2007 (UTC)

If you know that you aren't going to manage to produce a series of random heads and tails, is there any easy "mechanism" one could apply mentally to make your results random? One thought that occurred to me is to use odd/even distance between vowels in some text to determine change/repeat. Thus "And dId thOsE fEEt In AncIEnt tImEs" generates 44221223142 which might be HHHHTTTHTTT. ? -- SGBailey 13:35, 27 July 2007 (UTC)

When I am asked for just one digit, I wait a few seconds, then look at the second hand of my watch, modulo whatever appropriate number to get the right range. While this is hard to generalize to more than one digit (in a short length of time), it does avoid any artifacts caused by nonuniformity and nonindependence of letter distributions in the English language. You win some, you lose some...Baccyak4H (Yak!) 13:45, 27 July 2007 (UTC)

Well, if you're allowed to use some text, why not RAND's compelling 1955 magnum opus "A Million Random Digits with 100,000 Normal Deviates"? --TotoBaggins 14:26, 27 July 2007 (UTC)

So long as you start selecting from at least the second decimal place, this would be a good idea. Nothing like a little light bedtime reading. Baccyak4H (Yak!) 15:44, 27 July 2007 (UTC)

There's a joke waiting to be made about another Rand and intentionally senseless books. —Tamfang 03:45, 30 July 2007 (UTC)

I think there are some pseudo-random number generators that computer programmers use that are simple enough that you could do them in your head - and which have reasonably random outputs. You might need to remember (say) a four hex digit 'seed' number from one use of your mental randomizer to another - but that's not too hard. Something like the Gold code can be implemented using a Linear feedback shift register which you could easily simulate (in your head) like this:

One time: Memorize any 4 hex-digit number (representing a 16 bit binary number), it can't be zero but any other number will do. This is called the 'seed' number.

1. Whenever someone asks you to mentally toss a coin, recall the number you remembered - say "Heads" if it's odd or "Tails" if it's even.
2. When you have a free moment or two (but before you have to mentally toss another coin), do this:
   1. Since the number you are remembering is in hex, it's easy to find the bits at positions 0,2,3 and 5. If there is an odd number of '1' bits, add 0x8000 to your number - otherwise, don't.
   2. Divide the result by two - discarding the remainder. (I hope your mental arithmetic works in hex!)
   3. Forget your old number and remember the new one ready for the next time you have to mentally toss a coin.

I think the tricky part is remembering the new number each time...it would be really easy to forget the new one and remember the older one by mistake. However, imagining a set of 16 weird objects - one for each of the hex digits 0..15 and placing them next to each other in some ridiculous setting - might work. (eg There is a Cow pushing a complete set of printed volumes of Wikipedia against which is leaning "the platinum spork of terrible answers" and a bright green insectoid alien is running from them - so my number is 4F36 because that's 4 legs, the biggest thing you could possibly imagine(F is the biggest digit in hex), 3 tines and 6 more legs). Clever selection of the images to remember will make the extraction of the bits earlier go more quickly.

The resulting sequence of 1's and 0's is pretty random - it has the same number of ones as zeroes and it doesn't repeat until done it 65,535 times. Most computer programs use random numbers generated like this (although usually with a longer seed numbers and different sets of ).

Let us know how that works out! SteveBaker 16:16, 27 July 2007 (UTC)

The human mind does not generate good random numbers. When you have people think up "random" numbers they generally come up with the same numbers over and over again or gravity towards some numbers as seeming "more random" than others. There have definitely been experiments; if you look under keywords for "randomness" and things like that in psychological journal indices you can find lots of articles on these sorts of topics. They have been pursued by researchers since the 19th century at least, as they have implications to how well observers record data (see, for example, personal equation). --24.147.86.187 20:42, 27 July 2007 (UTC)

I recall hearing that when asked for a random number between 1 and 100, the most common choice is 37 and the least common is 20. I don't remember what research might have justfied this conclusion though. Dragons flight 20:47, 27 July 2007 (UTC)

Using the ground for a ground

Surely there are more ideal electical grounds than just running a pipe into the dirt.. do laboratories and things use big water pools or hunks of metal or something to take care of dangerous electrical potentials? --froth^t 02:19, 27 July 2007 (UTC)

As far as I know, and unless the ground is dry, a nice hunk of metal (doesn't have to be a pipe, but doesn't have to be anything too elaborate) gives you as good a ground as you're going to get. (And stop calling me Shirley.) —Steve Summit (talk) 02:31, 27 July 2007 (UTC)

For modern buildings, see Ufer Ground.

In an electrical generating station or substation, grounding is not achieved with a pool of water, or "hunk of metal." Instead, ground rods around the property at a number of locationsare driven to a sufficient depth (probably 20 feet or more) to achieve a stated low ground resistance, such as under 10 ohms each (or whatever the engineer specifies). A longer ground rod means lower resistance. Then these are connected by heavy cables. This may be bonded to the building steel and the rebar in the concrete and the incoming water main. Another trick, such as for a facility in rocky areas, is to install grounding electrodes in permanently moist soil such as a spring, or to install electrodes in a well, or to bury a wire mesh grid. A substation yard may have a grid of metal conductors buried below the gravel to achieve equipotential during fault conditions. A radio transmission tower at a broadcasting station is likely to have radial ground cables buried in trenches extending radially from it in all directions. Any of these can and does corrode over time, so after many decades it may be advisable to test the integrity of the system and the resistance of each driven electrode. Edison 17:10, 27 July 2007 (UTC)

So why do they use dirt? Just that it has a lot of water in it so it's really conductive? It seems like you'd be at the mercy of environmental conditions and have a wildly fluctuating capacity.. something I doubt is very good for electronics --froth^t 00:51, 28 July 2007 (UTC)

What do you mean, "So why do they use dirt?" They don't use dirt, they use the ground -- although as it happens, most often, the ground is made of dirt.

Sorry if this sounds sarcastic, or like a tautology, but that's the way it is. No, dirt is not a particularly good conductor, and wet dirt isn't all that much better. But it is (by definition) at ground potential, and it seems to dissipate charge well enough for most of our purposes. —Steve Summit (talk) 01:01, 28 July 2007 (UTC)

Here's a cute story about a grounding problem. Probably an urban legend, though. And for sure, there is no such place as "Winnepeg, Ontario" (or Winnipeg, Ontario, either). --Anonymous, July 28, 2007, 03:21 (UTC).

Industrial equimpment grounding (i.e. not antennas or transmission lines) is only to provide a reference for people. meaning that the building steel and structures and people are electrically connected to the ground. By tying the ground to one of the electrodes of the source (i.e. a tap to a transformer), electrical faults can be detected and circuit breakers tripped. No one wants to eneergize different parts of their house to two different voltages and find out by touching it. Therefore, everything that isn't power is grounded to the earth so that there is never a potential difference between people and appliances. The connection to the earth really only has to be as good as the persons connection to the earth. It would be bad if the person had a better connection to the earth than the electrical equipment. I don't know how different it can be but I suspect it can be dangerous. --Tbeatty 06:23, 28 July 2007 (UTC)

We are talking about a ground here, which means we are talking about a way to conduct electricity into the ground. "Running a pipe into the dirt" is the same as providing a path for electricity to flow into the ground. (ground = dirt) A metal pipe will provide a path resistance for electricity to flow into the ground. This method works. There is no need to sophisticate or complicate something that works as good as we need it to. Larger buildings may need more pathways or more effective pathways or both because of the amount of electricity needed to power them, but it all simplifies down to providing a path for the electricity to exit the circuit. With out the ground, AC electrical devices wouldn't work.Mrdeath5493 17:28, 29 July 2007 (UTC)

Actually, that last bit isn't true, in general. Except in unusual circumstances, the net amount of current flowing between a conventional AC circuit to or from the ground is negligible. The primary reason why grounding is important in electrical systems is for safety; secondary reasons are to reduce electrical interference, and perhaps to reduce various kinds of galvanic action and corrosion.

Most electrical circuits work perfectly well without a ground, and this is actually a bit of a problem, because if there's something wrong with your grounding, you might not notice it until a short circuit or other fault electrocutes you or starts a fire, when it should have (i.e. if a proper ground were in place) merely blown a fuse. —Steve Summit (talk) 02:55, 30 July 2007 (UTC)

Individual Timeline

My understanding of general relativity is that an object moving at near the speed of light in relation to a stationary object, would return to find that his native environment has far exceded his own. My question is what defines "near" the speed of light? Assuming my understanding is correct; wouldn't a fixed individual observing another individual simply walking away, or some other commonly exercised speed, differentiate the individual timelines of the two people? So therefore, isn't every individual living in their own personal space/time?
75.134.4.229 04:04, 27 July 2007 (UTC)Alan

This question is coming up on a near-daily basis and I would like to correct one misconception right away. While the "two twins" example refers to one twin traveling at high speed, general relativity refers to high energy and low energy objects. Traveling at high speed is merely one concept of a high energy object. So, "near the speed of light" means that the object contains more energy than mass. "At the speed of light" means that the object is all energy (no mass). Absolute zero (a complete state of rest) means that the object contains all mass (no energy).

As for time-lines, they do not exist. Time is merely a dimension. I can walk down the street. You can run. It doesn't mean we have our own individual streets. We just walked down the same street at different speeds. The concept of time-lines (aka world-lines) is used in science-fiction to do magic and make impossible things possible. -- Kainaw^(what?) 04:12, 27 July 2007 (UTC)

I don't know about your background, but worldlines were used in my graduate general relativity course to describe the motion of relativistic particles. Dragons flight 04:29, 27 July 2007 (UTC)

Note - you are not using the science-fiction version of world-lines. You do not use a concept that every particle exists in an infinite array of worlds and infinite number of times. While the names are the same, the concepts have nothing in common. I read the question as asking if each person on earth has their own little pocket of time that they carry around with them. I have my little version of time. You have yours. You can't see mine. I can't see yours. There is nothing in common between the two. That is why I thought of the science-fiction version of time and space. -- Kainaw^(what?) 05:11, 27 July 2007 (UTC)

Most relativistic corrections are proportional to something like $\beta -1$, where $\beta ={1 \over {\sqrt {1-{v^{2} \over c^{2}}}}}$, so relativistic effects become important when $\beta$ becomes larger than 1 to whatever degree of precision one cares about measuring. And yes, everyone has a slightly different experience of time, but the difference is miniscule for everyday speeds. Dragons flight 04:29, 27 July 2007 (UTC)

World lines only do impossible things if you decide to ignore the laws of physics. And to say a complete state of rest equates no energy, it would be more proper to say "no kinetic energy" (provided you're ignoring thermal and other fluctuations, but these would mainly apply to individual particles). "No energy" is also a meaningless concept. Everything has energy, always. There are many kinds of energy besides that of motion, and even vacuum has energy. Also, saying no mass at the speed of light, you must specify that you mean "no rest mass" (ie, if you were to slow the object down below the speed of light, it would have no mass, related to why it can't slow down). Someguy1221 05:00, 27 July 2007 (UTC)

As I stated above, I was referring to the science-fiction use of timelines, which are often called world-lines. I was not referring to the scientific term "worldline". As for "no energy" - it is, in my opinion, easiest to explain to a person who is grappling with the basic concepts of the theory of relativity that anything traveling at the speed of light is all energy and anything at absolute zero is no energy. If they take an interest in the topic, they can later work on determining the mass of a photon or the energy of an absolute-zero particle. Basically, I do not find it helpful to throw equations and complicated details at a newcomer to scare them away from the topic. -- Kainaw^(what?) 05:22, 27 July 2007 (UTC)

In general relativity (and in special relativity, though it's less often taught), the elapsed time between two events is the length of the worldline between them. Since different worldlines have different lengths, the elapsed time for differently moving objects can be different. There's nothing mysterious or mystical about this. It's only as strange as the fact that if two people take different routes between Chicago and New York, they'll end up with different mileages on their odometers. If it seems stranger than that, keep studying physics until it doesn't. -- BenRG 14:37, 27 July 2007 (UTC)

When people just walk around, their timelines do diverge and reconverge just like in the Twins paradox - but the difference between classical Newtonian stuff and reality at those speeds is so tiny that there is no way to even measure it. That's because at the heart of the math is this (1-v²/c²) term. 'c' is an ungodly huge number - and 'v' is tiny - so the answer is very, very close to 1.0 and you can't tell that anything weird is happening (although it is!). Even at a quarter of the speed of light (which is insanely fast), the differences between 'normality' and what's really happening would fairly hard to spot without doing some careful measurements - it's only when you get up at the 90% or so range when v starts to look a lot like c and that formula is starting to get noticably smaller than 1.0 that you start to see weird things happening. So there isn't some special speed at which relativity 'turns on' - it's always there - it's just that the effects are too small to see until you get very close to 'c'.

Theory Of relativity

Friends, Can any one explain the Theory Of Relativity in the most simplest way, B'cos any article I Read looks too complicated ??? Thank u.

You might be interested in this. Someguy1221 05:12, 27 July 2007 (UTC)

or this --Philc 14:18, 27 July 2007 (UTC)

Special Relativity (SR) all comes from the deceptively simple observation by Einstein that Galilean relativity—which is what lets you perceive, in your frame of reference, that you are sitting perfectly still even though the planet you are sitting on is rotating at 1670 km/hr—applies to all physical phenomena except the speed of light. Most of SR is extrapolating the implications from that—it ends up having all sorts of meanings in respect to the relationship between space and time.

But SR only works when you are thinking about frames of reference that are moving at a constant speed and in a constant direction—that is, frames of reference that are not accelerating (ergo the "special" aspect of it — it is not generalizable to accelerating frames). In formulating General Relativity (GR), Einstein addressed this issue, which, in turns out, hinged on a redefinition of what gravity is (instead of a "force", as Newton had it, it turns out to be that what we perceive as gravity is a warping of space and time in the presence of mass). The reason it hinges on this requires a bit more understanding of SR than you probably have, but if you worked your way through some SR it would make sense (basically a gravitational field behaves like an accelerating frame of reference, hence the relationship to the SR issue).

Taken together, SR and GR are considered the Theory of Relativity. Now that explanation barely touches the surface — it is but a brief conceptual/historical skimming — but I have found that thinking about it in those terms helps to make all of the rest of it make a little more sense: a lot of it is just extrapolation from a few somewhat simple axioms, which is how Einstein liked to do things. --24.147.86.187 20:15, 27 July 2007 (UTC)

OK - I'm awarding the platinum plated spork to [[24.147.86.187]] for this explanation. The OP doesn't understand any of the explanations out there - and you start handing out frames of reference and such. Argh. We need "simple" here!

Here we go with "simple"...(The pedants will probably tear this to shreds - but it's "good enough" for common understanding of this mind-bending concept):

If you stand still and throw a ball at 10mph, you see it heading away from you at 10mph. If a friend runs after the ball at (let's say) 3mph - then from his point of view, the ball moves at 7mph relative to him. If he runs at 9mph, the ball drifts slowly ahead of him at just one mph - and if he actually manages to run at 10mph, the ball seems to fly along right next to him at zero speed. This much is what we know and see every day - and we've known this stuff since the time of Newton and even Aristotle.

But here's the problem: An experiment by Michelson-Morley to measure the speed of light came up with some weird results - the upshot of which is that light is weird and special. If you flash a flashlight to send out a pulse of light (at the speed of light from your point of view) - and your friend goes chasing after it (REALLY fast...in a really, really fast spaceship) then the odd thing is that he sees your light beam flying away from him at EXACTLY the same speed you do. This is nothing like what happened with the ball! With the ball, the faster he ran, the closer he got to catching it. With light, no matter how fast you run, the light beam still shoots away from you at the speed of light!!! This is very strange. When you look at the lightbeam, you can see it moving at the speed of light. When you look at your friend, you can see him almost keeping up with it...but when HE looks at the light beam, he realises that he's not even close to catching it?!? Two people - two totally different ideas about what's happening! Which one of you is right? Well, both of you.

Einstein worried about that - how could it be that if your friend chased after the light pulse at 99% of the speed of light, you'd see him not quite catching up with it - but staying pretty close...but he would see the light shoot away from him at the speed of light - no matter how fast he runs?!?! It turns out that this rather strange situation comes about when you and your friend are moving at dramatically different speeds (like getting close to the speed of light). What happens is that your perception of time and distance gets warped...not just your perception of it...distance and time really does scrunch up when you move fast. If both you and your friend are holding nice large clocks - you'd see that his clock is ticking MUCH faster than yours is. He would see that your clock has slowed way down. That's why there is a difference in what you're seeing. From his point of view, you are imagining he's not losing much on the light beam because your brain is running slowly. From your point of view, you think he thinks he's not catching the light beam because his brain/clock is running so quickly!

The "why" of this...is really not known. "It just is" - that's how the universe operates.

At this point we could get into the math and frames of reference and other technical stuff - but the bottom line is that our perception of a nice, simple universe where clocks keep good time and things stay the same size no matter how fast they move - is ever so slightly wrong. But at speeds we can actually attain, this 'wrongness' is so subtle that we really can't measure it. However, when things start moving an appreciable fraction of the speed of light, time, space, mass...all of that changes depending on how fast you are moving compared to whatever it is you are measuring.

The "Relativity" part comes about from the observation that in space, you can't tell whether you are moving - and the stuff you are moving past is staying still - or whether you are stationary and everything else is moving the other way. "Everything is relative" I guess.

That's a much simpler explanation - it doesn't cover anything like all of the terratory. SteveBaker 04:12, 1 August 2007 (UTC)

Sea water

Why is Sea Water Salty, While rivers and Ground Water are perfect and have no Saline Charecterestics ??

Rivers are fed by rain and melting snow - which is mostly water. As it flows out to the ocean, it will pick up sediment, minerals, salts, and all. But, it will remain mostly water. The oceans are full of salt (have been for a very long time). It comes from the animals/plants living in it and the salts coming in from the rivers. Mostly, the salt just stays there. You can look at trapped salt lakes which were once parts of the ocean. Many years have gone by and the salt is still just sitting in the lake. -- Kainaw^(what?) 05:26, 27 July 2007 (UTC)

Agreed. Rivers with a tiny amount of salt flow into oceans, where the water then evaporates and leaves the salt. Over time, the salt content thus builds up in oceans and "dead seas", until it reaches the point where it precipitates out as salt beds and formations. Note that oceans and terminal lakes are also higher in many other dissolved minerals, for the same reason. StuRat 06:57, 27 July 2007 (UTC)

Is there any way to stop my budgerigar 'pleasuring himself'?

This sounds like a silly question and it's embarassing but I swear that I'm not making this up. I have an 14 month old male budgerigar who has recently started to masturbate using various objects in his cage. He'll hook his rear end under his perch, swing or ladder and hump away until he gets himself off. He's doing it several times a day now.

Is there any way to stop him or put him off from doing this?

Buy a female budgerigar and a bigger cage. ugen64 06:34, 27 July 2007 (UTC)

Looking after baby budgies is a big, big responsibility. I'm not ready to breed him yet. --81.76.8.159 07:01, 27 July 2007 (UTC)

On the bright side, the behaviour is probably seasonal; it's "high season" now in the Northern Hemisphere, but it will pass.

Atlant 12:30, 27 July 2007 (UTC)

Buy a webcam and make a little seed money. --TotoBaggins 14:29, 27 July 2007 (UTC)

Are you sure he doesn't maybe have an infection or an itch or something that's bothering him? I'd ask a vet. SteveBaker 15:29, 27 July 2007 (UTC)

Google for 'bird masturbating' comes up with a bunch of links Nil Einne 16:10, 28 July 2007 (UTC)

FTL

I don't understand why FTL travel implies time travel. Okay, it's fairly obvious that physically moving through space at a faster velocity than light is a scientifically meaningless notion. And clearly, any journey you make into your own past light cone results in a causality violation (which is what I understand as time travel). But what if I just instantly blip from here to Mars - specifically, a version of Mars which is currently "elsewhere", neither in my past nor future light cone? I can see why this would result in apparent time travel from the point of view of, say, an observer on Mars, who would see me arrive there before she the light of my departure from Earth reached her. But I don't see that apparent time travel is a contradiction and I don't see how a causality violation would arise. -- SamSim 09:26, 27 July 2007 (UTC)

But in some other reference frames, you will appear to have arrived before you left, according to special relativity. --Spoon! 13:30, 27 July 2007 (UTC)

Which is not a logical contradiction, just a possibly surprising result, like the twin paradox. You can add FTL travel to special relativity without contradiction. What you can't do is have a notion of FTL cause and effect (sending and receiving) which doesn't break Lorentz invariance. It should be easy to see why: you can always construct a trip of two consecutive FTL jumps which take you into the past light cone of your starting point. Nobody really understands the thermodynamic arrow of time, so it's not entirely clear what's really going on here. -- BenRG 14:24, 27 July 2007 (UTC)

I took a look at the article, but I don't understand what Lorentz invariance is, why it would be a bad thing to break, or how this instantaneous Earth-Mars blip (or two of them) would break it... SamSim 16:53, 28 July 2007 (UTC)

I can't think of specifially anything cataclysmic that would happen but I wouldn't want to be in the same universe as you when you tried it.. think about it, from the martians' refrence frame you're both on earth (they could look through a telescope and see you) and standing right next to them. I don't know if the big brain physicists have decided that something weird would happen but common sense tells you that if you teleport back it'll be impossible to interact with yourself since despite what the martians think, you weren't still on earth when you teleported back. But things are going to look mighty weird from the martians point of view- first some guy visits them for a couple moments but they still see him on earth, then he disappears and a few minutes later he disappears from their telescopes for a few moments and reappears. o_O --froth^t 15:38, 27 July 2007 (UTC)

Essentially the same thing as what froth said happens when you go faster than sound (only with listening) or even faster than brownian motion (when smelling). What you experience from your point of reference is what you see after accounting for that effect. — Daniel 23:06, 27 July 2007 (UTC)

Well yeah, sound and smell are one thing, but the speed of light is supposed to be the fastest that information can travel.. does the universe isplode if you can teleport instantly? --froth^t 00:54, 28 July 2007 (UTC)

primitive Weighing scale ?

What is the most primitive or rudimentary type of scale that a pre-metal or stone age society could invent? Something portable and easy to make from raw materials found in nature, but not metals. Maybe not so accurate, but better than nothing. For weighing herbs or drugs, not for entire humans. Maybe something using sand or a liquid?--Sonjaaa 11:07, 27 July 2007 (UTC)

The traditional scales is a wooden rod with a weight suspended at one end and held up by a string in the middle. At the other end is suspended the material that you want to weigh. The supporting string can be moved around against various marks to get a read out of different weights. This could have been made in the stone age, but probably wasn't. It seems that there is no picture of it in the weighing scales article! GB 11:29, 27 July 2007 (UTC)

Commons (http://commons.wikimedia.org/wiki/Weighing_scale) has a bunch of pictures (although the one I was really hoping for, with a witch on one end and a duck on the other, wasn't there).

Atlant 12:34, 27 July 2007 (UTC)

Hahah, I get it! Capuchin 12:38, 27 July 2007 (UTC)

Looks like we've got a joker on our hands.. you'd better watch out atlant :[ --froth^t 15:43, 27 July 2007 (UTC)

A joke at nobody's expense at the end of a helpful answer, that doesn't lead to confusion and misunderstanding, is absolutely not a problem. Skittle 22:22, 28 July 2007 (UTC)

I doubt there was a need for weighing things in the stone age. It's only when you have money or at least a very well established (and formalised) barter system that you really need to weigh things. If I have a chunk of meat that I don't need and you have a pile of nice ripe berries that you'd like to swap - we look, we haggle, we do the deal. It's only if I have a butcher shop and I'm selling meat at three groats per lump that you start to ask yourself whether I'm selling lumps that are smaller than the guy down the street who is also charging three groats per lump. A set of scales quickly allows you to set a price per pound that can easily be compared and standardized. In any case, scales and balances only COMPARE weights - without a set of standardized known weights, they aren't much use. SteveBaker 15:26, 27 July 2007 (UTC)

If a hunter or gatherer obtains food and eats it, he does not need to measure it. His stomach and the greater or lesser feeling of satiety or hunger is a wonderful measure of his success. But when agriculture is developed, and there is some standard of providing a part of the crop to the Temple or the Keepers of the Great Stone Idol, or to the Chief, or to the common granary, then measurement is needed. A gourd can serve as a "standard scoop" until it breaks. A Standard Holy Gourd of Taxation was perhaps the first unit of measure for volume. In the US flour is measured still by volume in recipes, while in many other countries it is routinely specified in grams. The greater precision of weight probably came along much later, but no metal at all is needed to make a beam type balance. Get 2 pans, show that the scale is balanced, put a standard weight on one pan (a little stone idol would serve admirably), add grain to the other until the beam is level, and there you are. Edison 16:56, 27 July 2007 (UTC)

Actually, your method for making a beam-balance is not correct. Just because the beam balances doesn't make it 'right'. If one arm of the beam is longer than the other - but the weight of the empty pans is unequal to the same degree (as is likely if you determine where to place the fulcrum experimentally) - then when you put weights in one pan and something to weigh in the other, you'll get the wrong answer. You can show this by piling up grain in pan A until it balances the little stone idol in pan B - then moving the grain into pan B and the idol into pan A. If it STILL balances then it's a fair balance - but the odds are good that it won't! SteveBaker 13:50, 29 July 2007 (UTC)

The simplest I know of is lifting and seeing how hard it is to hold up. The only materials it requires are a person with at least one hand and whatever you're weighing. — Daniel 23:00, 27 July 2007 (UTC)

The relevant article is Steelyard balance. --Heron 19:20, 29 July 2007 (UTC)

PINE TREE

HOW MUCH WATER DOES A PINE TREE TAKE UP FROM THE GROUND? Jamec IT LOOKS LIKE WHEREVER PINE TREE IS PLANTED, THE SOILS BECOME TOO DRY, E.G IN AUSTRALIA THE PLACE IS GETTING DRIER, IN S.AFRICA THEY STARTED UPROOTING IT AFTER KNOWING ITS BAD EFFECTS, ARE THE COUNTRIES PLANTING IT SAFE IN THE NEAR FUTURE OR THEY ARE ABOUT TO FACE CLIMATE CHANGE?

It depends on the type of pine, size and environment of the tree. -- SGBailey 13:23, 27 July 2007 (UTC)

Being evergreens, they by nature move less water than a deciduous tree. Gzuckier 14:36, 27 July 2007 (UTC)

From the pine article: "...they are fast-growing softwoods that can be planted in relatively dense stands, and ... their acidic decaying needles may inhibit the growth of other competing plants in the cropping areas". Contrary to Gzuckier, I'd think that fast growing trees would tend to consume a lot of water, especially in dense plantations. The other point is their inhibition of the growth of other plants; by doing this they can also lead to a very dried out soil, especially in hot conditions, as the soil will be more exposed to the air. However, as SGBailey said, it will depend on other factors like type, size, etc. Having said this though, it seems a long bow to blame their planting for climate change in countries that have planted them. --jjron 15:23, 27 July 2007 (UTC)

heh, sounds like Rainbow Mars... a giant tree absorbs all the water from mars and rockets with it to earth, where it dries up the entire planet --froth^t 15:45, 27 July 2007 (UTC)

According to [5](abstract only) a 100 year old lodgepine was observed that transpired 40-44L/day. That is only one specimen though. As noted above, it depends. 161.222.160.8 22:53, 27 July 2007 (UTC)

Solid bloodveins

Hey

I was wondering, why does some people, especially men have very visible and "strong" bloodveins that is visible through the skin over the biceps, and down over the underarms and at the backside of their hands?

I see that especially those who train and exercise alot tends to have this, while many other people again do NOT have visible bloodveins at all... I was thinking maybe it is because those people with "strong" and visible bloodveins have more oxygen in their blood - and it has always been said that it is a sign of good health a strong body. Something which to me sounds correct as I have learned that the more oxygen our blood are capable of taking in the better, for those with much oxygen in their blood often have good stamina and constitution and are stronger in sports/physical activities. And then it makes sense i guess that these things will improve by exercising, running or training in various ways that will improve our fitness and form. But we also see this often at older people that they have much visible bloodveins as well, so I don't know...

So, what is the reason for those strong visible bloodveins that some of us have? Is it indeed because we have more oxygen in our blood than some other people? I know that both things are normal, I'm just curious what is the reason, what makes it so? and does strong solid and visible bloodveins mean anything, like that we have good bloodcirculation or something?

Thank you, Krikkert

Krikkert7 14:08, 27 July 2007 (UTC)

Having very prominent blood vessels is due to having a low amount of body fat. --TotoBaggins 14:32, 27 July 2007 (UTC)

As Toto said, it is mainly due to low body fat (which, as you suggest, can be closely related to doing a lot of exercise). Additionally, as is commonly the case, genetic factors also have a significant influence, i.e., you could inherit the propensity to have prominent veins (as I have), so the vessels may be more or less prominent in different people with the same body fat. --jjron 15:29, 27 July 2007 (UTC)

Creationism

Is the only reason in the US that creationism is given any respect (i.e. more than other equally paradoxical, fallicious beliefs such as the tooth fairy) is the amount of people that would be up in arms if it was - rightly - dismissed as rubbish. How can people stand by and say its ok to complete refute centuries of hard fought scientific understanding in exchange for something written by one man with no basis and handed down by word of mouth. Philc 15:00, 27 July 2007 (UTC)

To make a career out of politics, a politician has only one goal - to get re-elected. Everything else is judged based on how well it helps re-election prospects. Apparently, many politicians feel that they need to show some support for creationism to be re-elected. As for why the public believes in creationism - most people do not know much about science. All they know (without valid reason) is that a bunch of evil white-robed men are continually trying to attack their belief in God and they have to grab at anything that makes them feel better. -- Kainaw^(what?) 15:17, 27 July 2007 (UTC)

Antidisestablishmentarianism. I think the problem is that the constitution effectively prevents religious teaching in government-run schools. The hard-core religious types want to get religion taught in schools by any means possible - and one possibility is to come up with a fake "science" such as intelligent design that imply religion yet are (perhaps) sufficiently legal to allow them to be taught. There are similar efforts in other fields - teaching the Bible as literature for example - and getting educational vouchers as a back-door way to get the government to pay for religious schools. All of these may be seen as attempts to subvert the ban on the government sponsorship of religion. SteveBaker 15:19, 27 July 2007 (UTC)

If the tooth-fairy was discussed in the Bible then that would also attract far more attention and support from the religiously minded, although it would not be as significant as the creationism issue. Since creationism/evolution deals with our origins - where we come from, who we are - it cuts deep into our psyches. It seems that some people (or in the case of the US lots of people) are unable to mentally deal with the reality that we originated via purely natural processes, as opposed to being a preferred creation of an all powerful superbeing. Why it is more prominent in the US than in other developed countries is a different issue that is also quite interesting. --jjron 15:42, 27 July 2007 (UTC)

It is more than "being able to mentally deal" with it. In the US the history of creationism is deeply tied into the history of religion in this country and the history of fundamentalism as a social and political movement in the 1960s. Why the US is different is a historical question, not a cognitive one. (If you are interested as to why that is, Ron Numbers' The Creationists is a great book on the subject, and very recently came out in a new edition which goes all the way through the Dover case!) --24.147.86.187 20:04, 27 July 2007 (UTC)

I think the questioner and some of the answers are confusing matters of faith with matters of science. Certainly the pope's latest comments shed light on the difference. Religion and science are not at odds. --Tbeatty 19:30, 27 July 2007 (UTC)

They are easily at odds if you don't accept your assertion that there is a difference between "matters of faith" and "matters of science." Such an assertion of there being a difference is itself a metaphysical position, one which many people (both religious and non-religious) reject. (Both the Pope and Richard Dawkins would agree that both religion and science make statements about the naturalistic world which cannot be reconciled, whereas a "compromiser" like Stephen Jay Gould would assert that they are different realms of description, for example.) --24.147.86.187 19:58, 27 July 2007 (UTC)

The question is more about society than either science or religion, although I find that the stereotypes of "religious" people are not getting any kinder with time... ◄Zahakiel► 19:39, 27 July 2007 (UTC)

Agreed, they are at odds to the degree that religion purports to offer an hypothesis about the natural world, or any other areas of knowelge, including the soft sciences. The religious method of inquiry is irrational (hence its based on faith, which is blind in nature), and thus fundamentally at odds with the scientific method that is based on facts and observations.Giovanni33 21:50, 27 July 2007 (UTC)

The problem is that science can't even answer the question "What is knowledge?" A tree, a rock, a star are all physical things. "knowledge" is less tangible. It is a metaphysical question that cannot be answered by science because it is a postulate of science that it exists. --Tbeatty 22:25, 27 July 2007 (UTC)

I think you're the one getting confused here. What the question answer seems to getting at is the way many Americans reject evolution outright and espouse creationism as a scientific alternative to evolution. Many scientists don't really give a damn about what people want to believe as part of their religion. However creationism is clearly not a science and treating it as such, or denying evolution as a scientific fact is ridiculous. But sadly, this appears to be fairly common in the US. Yes, there is a difference between matters of faith and matters of science. That's exactly the problem, many Americans including the current President don't seem to get that... Nil Einne 16:06, 28 July 2007 (UTC)

"Given any respect" — by who? It is not given any respect by scientists. If you are talking about "by politicians" then the answer is somewhat parasitic on whether it is given respect "by the non-expert public", and the reason it is "given any respect" by them is because it is bound up in questions about the role of religion in the United States, etc. --24.147.86.187 19:55, 27 July 2007 (UTC)

Just want to set a bit of perspective here: religion has been the force in human society for all of recorded history. Empiricism has only been around for about 400 years (though it was favored by aristotle) and has only become the popular belief in the last few decades. The belief in science is not the de facto choice, and many of you will look quite foolish a few centuries or possibly decades (if something significant happens) from now when mankind has moved onto some other popular philosophy and they make fun of the old scientists who rejected the metaphysical. In more mystical language: just because this generation lacks the faith to believe in the unobservable doesn't inherently invalidate such studies. The universe is indifferent to mankind's whims and any spirit realms there might be out there aren't going to poof out of existence just because man declares it off-limits to their science. Not everyone follows the same thought patterns- some can accept the idea of believing in the unobservable, while some find it ridiculous because they must be able to prove everything they believe. But that's not the only way of doing things.. --froth^t 01:07, 28 July 2007 (UTC)

You seem to be getting confused here. Most scientists don't say the 'spirit realm' is off-limits to science. In fact, it is the believers that say so. Instead, scientists say that if the 'spirit realm' really exists then why can't we observe it? And believers say, well it can't be observed in any way shape or form but you should still believe it's there because I say so... Nil Einne 16:02, 28 July 2007 (UTC)

OK fine. My point is that there's no telling who's right- the only thing in support of the view that things must be observable to have meaning is science.. and the scientist is basing his whole method of reasoning on science. The only thing in support of the view that things can have meaning without being observable is faith.. and the believer is basing his whole method of reasoning on faith. Scientists are so smug in thinking that their way of thinking must be the best (if they even recognize that it's only Yet Another way of thinking) since it's the most recent, but recentness is only valued within their own realm of science! The truth is, they're new at this game and that's not necessarily a good thing, though they'd say new is best --froth^t 23:47, 28 July 2007 (UTC)

You just can't put religion and science on the same level as philosophies like that. It's not just 'yet another faith'. Where science clearly deviates from other philosophical standpoints is that it proceeds step by step in a methodical way from known things - advancing by mathematical proof and careful experiment. Science makes predictions that can be tested. These things mean that the chances of science being proved wrong in any major way is as close to zero as anything we know. The idea that in a few decades, centuries or millenia, we'll have found something as an alternative to science is just laughable. I suspect we may increasingly demand more rigor (as mathematicians are tending to do) - I would imagine other changes in methodology - but at it's core, a philosophy of life that is grounded solidly on reality with demonstrable step-by-step proofs is here to stay - and that's all that science purports to be. All religion is unfalsifiable - science rejects anything that's unfalsifiable and that's a black-and-white distinction. You can't deduce anything from religion - it's a dead end based on wishful thinking. SteveBaker 13:42, 29 July 2007 (UTC)

I'm not impressed by science's ability to prove itself- the obsessive need to correctly describe the external world is just another philosophy, and one that's not necessarily permanent or even valid. It seems to be evolutionarily beneficial at this point in humanity's existence so it's burned into our brain paths or whatever.. but there's no reason that can't change on a fundamental level. You've referenced a possible revolutionary scientific discovery that could change scientific theories (but not methodology) as we know it.. but you're ignoring a higher-level possibility: a significant change in the way people think. Like I said, it's happened before. This interest in science and -to a more basic degree- rationalism is rather recent and hasn't existed for quite a bit of recorded history (let alone all of human history), let alone enjoyed popular belief. While science may very well be correctly describing the universe, I have my doubts that any humans will care throughout large tracts of our future (in fact I wouldnt be surprised if a recurring focus on science turns out to be a rather minor part of human history once it's all said and done, though I guess the same could be said by others of others- like religion).. and I have my doubts that correctly describing the universe has any kind of cosmic significance whatsoever. Like I said, just a little bit of perspective on the great and mighty Empire Science. --froth^t 02:14, 30 July 2007 (UTC)

I don't understand anti-science feelings. What I can understand is being opposed to the arrogance of those who say things like "science is #1, and religion is bunk". But again, there's not a good reason to doubt "science's ability to prove itself". The way it proves itself, such as relying on materialistic explanations, is the only way science should work. Coming up with metaphysical explanations may be good in explaining the unexplainable, but it doesn't help in advancing scientific knowledge.128.163.224.198 18:56, 1 August 2007 (UTC)

It's true that in casual conversation and when speaking less-than-carefully, people can seem to put just as much faith in science and the scientific method as religious types do in their various bibles and belief systems. However, even more importantly than the step-by-step nature SteveBaker described, a key concept of true science is that it carefully, deliberately, and explicitly denies faith. No one is required to take any scientific result on faith; everyone is free (nay, encouraged) to suspect it, to doubt it, to question it, to attempt to reproduce it, to attempt to falsify it, to suggest alternative hypothesis. Moreover, everyone who publishes a result is obligated to provide, on a silver platter, all the prerequisites and methods by which the new result was derived, making it maximally easy for anyone else to reproduce (and, perhaps, to falsify) the result.

Also, science understands, and attempts to make allowances for, human foibles and (mis)behavior. Scientists are people, and they're prone to the same kinds of rivalries and jealousies as anyone else. However, responsible scientists and scientific journals erect guidelines and rules which are supposed to ensure that scientific truth is determined by actual science, not by tenure or tradition or inertia or prestige or politics.

Since scientists are people, they do make mistakes, and one can point at various reasonably egregious examples of how science has occasionally, in practice, fallen short of its ideals. (One well-known example, discussed by Feynman, is mentioned on our Millikan oil-drop experiment page.) However, over time, the process does discover and correct its mistakes, and scientific truth inches asymptotically ever closer to reality. —Steve Summit (talk) 15:57, 29 July 2007 (UTC) [edited 20:29, 29 July 2007 (UTC)]

I did the Millikan experiment when I was in high school - it was almost impossible to get it to work - we had errors over 100% - at which point (because the experiment relies on calculating integer multiples of some common number), we could get no conclusive results whatever. It's frankly astounding that Millikan came so close to the correct answer. But it's certainly telling how people were prepared to err on the low side to try not to throw off Millikans' result by too much. Feynman was my hero...quite possibly the smartest person ever to have become a scientist. SteveBaker 01:01, 31 July 2007 (UTC)

Bear in mind the influence of religion in American cultur, society & politics appears to be far greater then most other developed Western countries. Nil Einne 15:55, 28 July 2007 (UTC)

WHY do people constantly think its either all or nothing?? What if man evolved on a different planet eons ago, and then either came here or was brought here. After these travelers original machinery, devices, and technology education began to fail, they hit upon easy to understand similies to explain what happened. "War in heaven, fall from grace, garden of eden, etc". ) If you think about it we really have no fossils of any transition man do we?? There should be billions of artififacts but they only come up with an only occasional "piltdown man" (already proven to be a fake to hype media attention to the fakers). WHERE are all the fossils? We find the dinosaurs and every other creature but no "Transition Man" ? WHY? Maybe its because T-Man evolved on another planet far far away ! This makes both creationism (space travelers came here and reproduced, they were eventually thought of as GOD because they knew how to manipulate even the genes and atoms of nature), and truly these ancestors of man did evolved but just not on earth.. End of arguments.. both are correct with a little modification. TripleBatteryLife 19:07, 29 July 2007 (UTC)

Er, actually there are dozens of intermediate fossils between what we consider humans and what we consider non-human primates. We even have an article about it called: List of hominina fossils. Why not check it out rather than spouting a bunch of nonsense about evolving on another planet? Matt Deres 21:11, 29 July 2007 (UTC)

Yeah - I agree, this is a commonly used argument put out by the creationist/intelligent-design nut-jobs - but it's not true. We have a pretty clear step-by-step set of fossils. Sure, there is the occasional gap - but we aren't talking about: Fossil #1: A marmoset, Fossil #2: A modern human. We're talking about: Fossil #1: A skull very similar to a modern human - with almost identical brain size, 2mm longer canine teeth, 10% larger brow-ridges, and 15 degrees more forhead slope, Fossil #2: A modern human. Do we have a protohuman fossil with 5% larger brow ridges? Probably. How about 2% and 7%? Maybe not - that's a gap - but it's a tiny one. But fossils are actually very rare - the conditions required to form them are exceedingly special. We can't dig up every square inch of the earth's surface to a depth of a few hundred feet to look for them. It would be surprising (and perhaps even a little suspicious) if there were no gaps whatever. We find dinosaurs - yes - but there are gaps in their history too. As time goes on, we find more skulls and the gaps get smaller. Once in a while, we find something weird (the "Hobbits" for example) that causes a branch and maybe a gap. But like I said - there are bound to be the odd stubborn gap. But please - don't take my word for it - take a trip to a decent natural history museum (pick one in a big city who have a decent stock) and look at the evidence yourself. Somewhere there will be a showcase full of skulls - lined up in a row from something more primitive than a chimpanzee to a modern human - the difference between any two adjacent ones is noticable - but not enough that you'd seriously doubt that one could have come from the other - that's not a horribly flawed gap-ridden historical record as the intelligent design people would like you to believe. It's a pretty convincing demonstration of what we believe is true. Ask really nicely at a large museum (preferably call in advance) and some staffer may even offer to take you behind the scenes to rows of boxes on shelves where you can see a bunch more skulls.

You are correct in saying that it's POSSIBLE for both theories to be true - that some creatures evolved whilst others were popped into existance by magic. But it's not NECESSARY. This business of not believing things that it's not necessary to believe in - always going for the most simple, most mundane explanation - is very important. Scientists call it "Occams Razor" - and whilst it's not always true - it's always proven to be a damned good first guess. Newton didn't think to worry about his laws of motion maybe being wrong at insanely high speeds - he didn't need to, he used Occams Razor to make the assumption that his low-speed experiments would hold over all speeds. In that case, he was wrong. Only when later experiments showed some surprising results were people driven to look for the more complicated answer that Einstein came up with. But that's a very rare thing...almost always, the simplest answer is the right one.

It's like you look into your sock drawer tomorrow morning and find 10 identical pairs of black socks in there (just like on the previous night and the night before that). It's POSSIBLE that some devious/weird pervert/cat-burglar broke into your house during the night, stole 5 socks and replaced them with 5 almost identical ones - then snuck away without leaving a trace! You can't prove that didn't happen...you really can't - but you don't go around believing it for no particular reason. People who suspect burglars are swapping out socks in the middle of the night wind up in the padded cells wearing a jacket with unfashonably long sleeves! Why would you think that? You'd also have to admit the possibility that space aliens also swapped out a few socks using a sock-o-matic raygun - and that some of them were teleported away to another astral plane by deamons but were returned by kindly angels who spotted the problem. There are quite literally an infinite number of unnecessarily complicated theories you can come up with for every single thing that ever happens to you. But you naturally seek the simplest possibility...that your socks stayed in the drawer the entire night.

A belief in God (or gods - or that intelligent design coexisted with evolution) is every bit as unnecessary as these wild theories you seem to be having about socks recently! If you're prepared to believe that your socks stay put - then why not believe the super-simple, self-evident, easily demonstrated theory of evolution? Gods are not necessary for the functioning of our universe - over the last century or so, we've gained enough knowledge to explain things down to the smallest and largest things humans can detect - we have great explanations for everything beyond maybe the first couple of nanoseconds of the life of our universe - we know how and when (more or less) the earth will end - and we're down to just a couple of options for getting a good idea of how the universe will end. It's pretty clear that we have fairly mundane explanations that make everything tick along just fine with very simple laws of nature.

SteveBaker 00:44, 31 July 2007 (UTC)

Its neat that you still have no link between what most would call ape and what most would call intelligent human! If so put up instead of spouting a plethora of "specie" none of which are what I would call "TRANSITION MAN" ! And if this transition man exists in quantity, where are the millions of fossils from him? waiting. —Preceding unsigned comment added by 209.16.117.50 (talk • contribs) 20:06, 31 July 2007

1. We have plenty of links between apes and humans. But they're not creatures halfway between apes and humans; they're not steps on a hypothetical chain by which humans descended from apes. Because humans didn't descend from apes -- we each descended from a common ancestor.
2. We don't have millions of fossils of anything. As Steve Baker pointed out, fossils are exceedingly rare. It's rather remarkable -- and a testament to the persistence of paleontologists -- that we have as complete a picture of the prehistory of modern life as we do.

—Steve Summit (talk) 23:15, 31 July 2007 (UTC)

OK Mr/Ms 209.16.117.50 - I'm not going to "shut up" - this stuff is fact and it's right to explain facts to those who don't understand them. So instead, I'll be more than happy to "put up".

First, let's clearly lay out the ground rules: Firstly - and very importantly, neither I, nor the expert evolutionists claim that we evolved from the chimps, or the apes, or any other animal that's still alive. The claim is quite clear: Humans and chimps both evolved from a common ancestor - a creature that has long gone extinct because both the proto-chimps and the proto-humans out-performed it.

So I guess that by "Transition Man" you mean a fossil of a pre-human who is midway between modern man and the last common ancestor of both chimpanzees and modern men? If that's not what you mean - then tell us clearly what you DO mean by that term. Meanwhile, I'm going to assume that this is what you seek.

Well, sure! No problem whatever!

"TRANSITION MAN"
(Australopithecus africanus)

It's been calculated that the last creature that was the ancestor of both chimps and humans lived somewhere around 4 or 5 million years ago. Fossils of Orrorin tugenensis and Ardipithecus from that sort of era clearly have features common to both modern human and modern chimp and to no other modern creature. One of them is the ancestor of all humans and all chimps - and fossils from FIVE of these animals (found in Kenya) are carefully preserved in a handful of museums where you could (in principle) go and see them. But these represent the fork in the tree. They are still pretty different from either chimps or humans. So what happened in the transition between then and now? Well, please turn your attention to: List of hominina fossils - it has references and photos for fossils at intervals of about 100,000 years everywhere between the time of Orrorin (maybe 4 million years ago) to the present day. So - which of the dozens of fossil species between then and now would you like to pick as your "Transition Man"? Let's pick one chronologically halfway between us and Orrorin - that would be maybe 2.5 million years ago. There you go: "TRANSITION MAN" (in your terms)...is 2.5 million years too old? OK then we have Homo ergaster fossils from 1.5 million years ago, or Homo_erectus from 700,000 years ago. Maybe 2.5 million years is too close to modern humans to meet your criteria? Well, how about Kenyanthropus platyops from 3.5 million years ago or an almost complete skeleton of Australopithecus afarensis from 3.8 million years ago. I mean, really!

What exactly do you need that we don't have?!?

Now, you wonder why there aren't "millions" of these fossils. That's simply because fossils are really rare - even fossils of common creatures are rare. Realise that the earth didn't have 6 billion proto-humans living on it. We were rare animals back then - it's only with our spread throughout the world and our discovery of fire, tools, agriculture, cities that we got above a million people. Even as recently as the time of the Egyptian pyramid builders, there were less than ten million people. There are probably only 150,000 chimps alive right now - there may have been that few proto-humans alive a million or two years ago. For some of these intermediate species, it's quite possible that less than a million of them ever lived. But even if there were millions of them - how many would end up fossilised? For a fossil to form, you need a really lucky set of conditions:

• the creature has to die someplace it won't be ripped apart by scavengers.
• it has to be buried completely in rather special chemical conditions so it won't decompose too quickly.
• that burial has to happen fast enough to ensure it doesn't decompose before minerals can leach into it and form a rocky cast.
• then, it's no use if that happens where the earth is being subducted underground or sinking into the ocean or eroded away by wind/rain/water.
• it has to end up where we might find it. We need it to form someplace close to a modern rock quarry - or a cliff or where we excavate a mine or deep building foundations or something. If it's buried even 5 feet into the cliff face, we'd never find it.
• even then, it has to form someplace where paleontologists are actually looking.

All of this (along with the relatively few numbers of these creatures in the first place) means that we don't expect to find more than a few of each - it's just really, really unlikely.

Someone earlier asked how come we have so many Dinosaur fossils and so few proto-humans. Well, we have lots of Dinosaur fossils because the dinosaurs were around for 160 million years - we've only been here for 4 to 5 million. There were thousands of species of dinosaurs - and they were the dominant life forms in all sorts of habitats, so there were a heck of a lot of them - so we have lots of fossils. Early humans probably only lived in small areas of Africa and southern Europe. But we have quite a few fossils - statistically about what you'd expect - and ENOUGH TO TELL THE STORY. Note, for example, that we have a LOT more proto-human fossils than we have proto-chimpanzee fossils - so we've been fairly lucky in that regard.

Did I 'put up' adequately? I'd be very happy to expand on any part that you didn't understand - if the fossil you have in mind for "TRANSITION MAN" isn't what I described - please get back to me and tell me exactly what you are missing and I'm pretty sure I can find it for you. The thing is, this evolution stuff happens to be the truth - so there is plenty of evidence for it. SteveBaker 03:34, 1 August 2007 (UTC)

TripleBatteryLife 21:00, 1 August 2007 (UTC)

RESPONSE : 1st. Your transition man looks too perfectly human to be a true transition. 2nd. For a transition to occur from perfect ape to perfect human you would have to have a transition time of perhaps millions of years. Where is the fossil evidence of the perhaps millions of variations that would have to be there? You fail in that also. You would have us believe on "faith" that ape LEAPED to pefect man in one birth? Strange for a scientist to believe in statistical impossibilities. So you who say you do not believe in faith base your whole "belief" system on faith in LEAPING THE GAP! Is it a religion you belief? If so what is the name ? : The LEAP FROGGERS RELIGION of Stubborn Refusal to accept the data? In truth there would have to be massive fossil remains of perhaps 100,000 or more at least, different variants, of the necessary progressive mutations from ape to man for any scientist worth his/her salt to believe it. Sciences best friend is the data. Your data shows the first men pehaps but not all the massive variants that are mandatory in evolution. SO THERE IS A GAP you can't explain except by your own religion of LEAP FROGGING! Do you see how silly the lack of data makes it sound? 3rd. You say you believe in the speed of light and the theories of relativity. This makes you believe that time dan dilate (spec theory). This in turn makes you accept that time could go backwards (as some religions speak it did once for 14 minutes). If that is so then how do you know for sure that someone or something did not go back in time and might be at your elbow even now? (0r do you believe anything supernatural must be an undigested bit of potato as scrooge said?). Also if you believe in relativity then you must accept that that would make interplanetary travel very much easier. still waiting for the massive residual fossil evidence of the missing GAP that would require at least 100,000 different mutations including the one thread that led to man. Se Le Vie! TripleBatteryLife 21:19, 1 August 2007 (UTC)

Replying to you point by point:

1st: OK - so you want something that looks less human - so go back a million years or so - the further you go back in time from now back towards that common ancestor of chimp and man - the less human they look. If you would PLEASE just take a moment to read List of hominina fossils - you'll see (for example) Australopithecus afarensis from 3.8 million years ago - it looks nothing like a modern human - yet it has features that no chimpanzee has - and that all humans have. But then you'll probably say that it looks too 'apelike' - OK so come back through the list of our ancestors on that very same List of hominina fossils page and you can pick something that looks as human - or as apelike or anything in between...truly - don't take my word for it - GO AND LOOK!

2nd: You demand evidence of the millions of inbetween variations - but as I explained, that's impossible because fossils simply don't form that easily - and we don't find them that easily. But the gaps are SMALL - it's not like we don't have a really good range of body forms ranging from one extreme to the other - we do. I'm absolutely not demanding you leap from "perfect ape" to "modern man" on one leap. I'm asking that you take 100,000 year baby-steps because we have fossils (as you will clearly see if you bother to actually look at List of hominina fossils instead of pretending that it doesn't exist. We have documented evidence for about 40 different steps between the last ancestor of chimp and man - and the present day. That's pretty good. Each step looks a lot like the one immediately before it - the variations between (say) the 2.7 million year old fossil and the 2.8 million year old fossil are comparable to the differences we see today between someone with one set of facial features and another. Those two fossils are so amazingly similar, it takes a trained paleontologist to tell the difference - I very much doubt you and I could. Heck - you think that the 2.8 million year one already looks like modern man - so no huge, unleapable gap over the last 2.8 million years.

You also say that we scientists are floundering around struggling hard to explain these gaps...I really don't see where you get that idea from. These gaps are very easy indeed to explain - I already did so in fact. FOSSILS ARE VERY RARE. There - that's the explanation. We don't have a fossil for every generation over the past 4 million years because that would be something like 200,000 fossils - and the total number of human fossils that have been found from all of history is probably a few hundred at most.

Please just stop and think about this for a moment. If you were right - and fossils are actually common enough that we could find them through all of history and there were indeed massive inexplicable gaps - then we'd have (say) 1000 Kenyanthropus platyops fossils from 3.5 million years ago - then an inexplicable gap - then maybe a couple of thousand Australopithecus afarensis fossils from 3.8 million years ago...but we don't! We have maybe a couple of each. Those fossils that we DO have are roughly equally spaced out over time - that's not indicative of big, mysterious gaps that we need magic to fill - it's indicative of fossils being very rare. We know they are rare from independent work - did you know that we didn't find the first chimpanzee fossil until just two years ago? Yeah - fossils are rare - so you can't have a million of them to fill in the gaps. So - there's your explanation - we have some 100,000 year-ish gaps because we only found a few hundred proto-human fossils and statistically it's not at all surprising that they are spread out the way they are. Far from this being a horrible flaw in the theory of evolution, it actually backs it up. If we had a million human fossils and only a few tens of thousands of dinosaurs - then we'd be wondering what was wrong with the theory.

But here - let me ask you a question. If you believe that some magical being stepped in and made mankind all in one go - when did that happen? Between which pair of my steps? Because if you pick a time period thats fairly close to the present (say: 70,000 years ago) - then we have much larger numbers of fossils between 100,000 years ago and today and the 'gaps' such as they are are very small indeed. If you choose a period older than that (suppose mankind popped into being 2 million years ago according to your theory) - then you are saying that some creature evolved from 4 million years ago until 2 million years ago - then *poof* some magic happens - then mankind evolves for another 2 million years to get us where we are today. Which of the 100,000 year-wide gaps are you going to choose? Pick carefully because maybe tomorrow someone will find a fossil slap bang between your two limits and now you're in trouble because you only have a very tiny gap between the creature who existed just before the *poof* event - and the one afterwards. There may come a time when that gap gets so small that you wonder why God bothered? I mean - the creature he 'designed' is so amazingly similar to the one that was already evolving away happily towards the same destination?! But don't let me put words into your mouth. Tell me - when did the *poof* event happen?

3rd. Yes, we're pretty sure about relativity too. I believe that time can dilate for an observer in a different frame of reference IF our frames of reference are moving at some significant fraction of the speed of light. This does not in ANY WAY make me accept that time could go backwards...nope - sorry - go read what that nice Mr Einstein actually said and not what the religious nuts are telling you he said! Unlike religion, science documents every step of the way, clearly, and publishes it for everyone to read. Take the time - go read it. Modern physics makes it pretty evident that backwards time travel is impossible.

You ask whether I believe anything supernatural must be an undigested bit of potato - well, I wouldn't have said that. I would have said that everything we typically label as 'supernatural' is complete and utter bullshit...all of it. That's why we invented the word...it means "everything that we can't demonstrate in a carefully controlled experiment...or something like that.

You state (very, very incorrectly) that if I believe in relativity then I must accept that that would make interplanetary travel very much easier. Nope - quite the contrary - it makes it ridiculously difficult. The faster you approach the speed of light - the more power you need to get there - and as you start to get up into relativistic speed - you need exponentially more fuel/energy to do that. No - I most certainly don't believe that interplanetary travel is easy...it's ridiculously difficult.

You say you are still "waiting for the massive residual fossil evidence of the missing GAP that would require at least 100,000 different mutations including the one thread that led to man". I'm interested to know why you feel the need to see so many. Over 4 million years with a generational span of (let's say) 20 years - you are demanding to see one fossil for every two generations. Surely you know that evolution doesn't happen that fast! Compare the skull of an ancient Egyptian mummy from 8000BC to a modern human and you won't find any differences large enough to measure. Over 10,000 years we don't need more than a couple of fossils to show small steps of change. We have them about every 100,000 years - well, yeah - we could wish for more.

But you really are missing the point. You are looking to find a way to wedge your intelligent designer into a huge span of evidence leading from mankind back to the first bony fish...even further perhaps. Scientists are saying "Here we have a really simple explanation for how life arose on Earth - we can see evolution happening all around us - everything from lactose tolerance in modern man to how bacteria in hospitals manages to evolve to avoid being killed by our antibiotics. Every single piece of evidence that we've ever found fits beautifully into that simple theory. The only two things we have to know are that:

1. The DNA/RNA molecule changes over time due to random mutation and sexual reproduction. Since the 'design' of an animal or plant comes from those molecules, animals and plant MUST change over time.
2. If one animal has a random DNA change that makes it better able to survive - it will survive when it's relatives do not.

If those two things are true - then evolution is inevitable - you can't even concieve of a way to stop it from working to change entire species over time. If species were NOT changing over time - we'd be at an utter loss to explain why not!

So why do we need to invent (without ANY evidence) some kind of magical intervention in the case of modern man? The exact same mechanism that gave T-Rex his enormous jaws and big counter-balancing tail explains how come the TB disease is getting harder and harder to cure - it explains why it is that all other mammals lose their ability to digest milk soon after being weaned - but most humans do not. It explains all of everything that we see around us in the natural world. It's a truly beautiful explanation - it's so simple that even I can understand it - and it explains everything. What's not to love?! ...unless of course you're worried that it puts your supernatural all-powerful being out of business? SteveBaker 23:20, 1 August 2007 (UTC)

You still haven't provided the massive residual evidence that your theory requires to be authentic. There must be millions of years of transition variants from perfect ape to perfect man, where are these massive amounts of residual fossils? DNA variants would many many many but you have none in quanties needed to validate your theory. I daresay if you were born in the 1700's you would teach that manned flight was impossible and would never happen because after all your studies didn't teach you that. Can you seriously say that you never had anything spiritual or supernatural happen to you ever ever ever? Most people when allowed time to reflect say yes sometimes things happen that are unexplainabble. Your theory requires faith (Ie LEAP FROGGER RELIGION) to accept the trust you have in yourself, your parents, your teachers, society, technology, on and on, including that by some mysterious (miracle) method Ape transitioned to perfect Man in only one mutation? Amazing faith you have! ! But that would be statistically impossible and so you choose to believe anyway by blind faith. That is your religion just as faithful as any in that you don't need the required data to substantiate your theory. Any scientist worth his salt would never believe a story such as yours (earth only ape-man evolution) without the required massive fossil evidence of all the different variations that would have to be there . This is why BOTH evolution and Creationism can both be true. Yes the good spirit evolved (somewhere sometime probably far far away) and then created man! The data is your friend always. Ignoring it is your enemy always. WHERES DEM BONES!! —Preceding unsigned comment added by TripleBatteryLife (talk • contribs)

You mean the transitional fossils? Also, you know that evolution would predict that the current forms of "ape" and "man" are descendants of a common ancestor, not that "current man" descended from "current ape", right (that is, there may not be anything resembling a half-way intermediate between the current forms)? DMacks 04:03, 2 August 2007 (UTC)

Like most of these intelligent designe/creationists - User:TripleBatteryLife doesn't read what people write - and they refuse to answer reasonable questions such as the ones I asked in my previous postings. If this person were to tell us when he/she believes mankind appeared on the scene, we could rationally discuss the nature of the 'gap' into which this event falls...but TripleBatteryLife won't do that because that allows us to apply scientific rigor to this half-baked theory which will immediately cause it to collapse. So instead it's better to keep flinging the same old tire "leapfrogger" nonsense and hope that some of it sticks. I've carefully explained (twice!) why massive quantities of these fossils are not there - the fact of their non-existance is precisely what the theory predicts. We are beyond the point where we need to find new fossils to validate the theory. There are indeed enough fossils around to show quite clearly the stages of evolution between the common ancestor of human and chimp. The case is proven beyond all reasonable doubt - we're just having problems with the unreasonable doubters. I've been accused so far of believing in reverse time travel and that interplanetary travel must be easy because of relativity(!) - which clearly proves that TripleBatteryLife understands very little about mainstream science!

To address the lastest set of bizarre things:

DNA variants would many many many but you have none in quanties needed to validate your theory. OK - this is ungrammatical gibberish - but I think he/she is asking why we don't have DNA evidence. Well, we don't have DNA from fossils because...THEY ARE CHUNKS OF ROCK...no biological material remains in them - so no DNA could be extracted. We DO have evidence of a common ancestor of chimp and man in that mankinds DNA is more similar to a chimpanzee's DNA than that of any other creature. That makes us "close" on the evolutionary tree.

I daresay if you were born in the 1700's you would teach that manned flight was impossible and would never happen because after all your studies didn't teach you that. Well, the first balloon was invented in 1709 - so clearly some people who were born in the 1700's were perfectly able to conceive of the possibility of manned flight. But either way, that has no bearing on this. It's hard to predict what will or will not be possible in the future - but we aren't talking about the future - we're talking about the past. The past is an entirely different matter - we have the evidence.

Can you seriously say that you never had anything spiritual or supernatural happen to you ever ever ever? Most people when allowed time to reflect say yes sometimes things happen that are unexplainabble.' Yes, I can seriously say that never happened to me. Unexplained and unexplainable are two different things. I can't explain how that dog across the street from my window got there - does that make it a spiritual event? No - its "unexplained" but it's not "unexplainable".

Your theory requires faith (Ie LEAP FROGGER RELIGION) to accept the trust you have in yourself, your parents, your teachers, society, technology, on and on, including that by some mysterious (miracle) method Ape transitioned to perfect Man in only one mutation? Amazing faith you have! ! Aaaarrgghhhhhh!!!! Please, PLEASE listen!!!! Neither I nor anyone else who understands evolution ever claimed that ape transitioned into man in one mutation! NEVER! I tell you again - look at the List of hominina fossils - each step from one proto-human to the next entails one or more mutations. We are claiming not one step - but dozens and dozens of steps. The last few steps have happened within recorded history - lactose tolerance for example is believed to have happened within the last few thousand years - and it's not over yet. *IF* we believed this happened in one step - then you'd be right to chastise us for a flakey theory...but that's not what we claim. Many steps - dozens, perhaps hundreds of mutations. OK - so what about 'faith'. Again, No - you misunderstand. It's not faith - it's KNOWLEDGE. I've read Darwins works - I don't believe it because Darwin said so - I believe it because I can follow his reasoning about the Finches and the other examples he comes up with. What he says makes logical sense. I've seen fossils in a museum - I understand how evolution works and I've decided on the basis of that knowledge that this is a perfectly rational explanation that doesn't require magic or other things that have to be accepted without evidence. Even if these "gaps" were such damning evidence against evolutionary theory - what evidence do we have to the alternatives? How do we explain the fossils we do have if mankind "poofed" into existance by magic. How come we don't see other evidence of that?

But that would be statistically impossible and so you choose to believe anyway by blind faith. Sure - a single step WOULD be statistically impossible - and I don't believe that. However, lots of tiny mutations are statistically NECESSARY. When you have a molecule the size and complexity of DNA, it's statistically impossible that it could be copied so many times WITHOUT mutations. Far from being statistically unlikely, the idea that animals DON'T mutate is statistically impossible!

That is your religion just as faithful as any in that you don't need the required data to substantiate your theory . - No - there is a fundamental difference. Religion requires you to take the most bizarre claims on faith "because I say so" (where "I" is a priest or some other nut job). Science requires only that you listen/read the arguments, examine the evidence and believe or not believe on the basis of what you find. It's a totally different modus operandii.

Any scientist worth his salt would never believe a story such as yours (earth only ape-man evolution) without the required massive fossil evidence of all the different variations that would have to be there . -- WHAT?!?! Almost every scientist believes precisely what I've been explaining! Check out (for a silly example) Project Steve.

This is why BOTH evolution and Creationism can both be true. Yes the good spirit evolved (somewhere sometime probably far far away) and then created man! The data is your friend always. Ignoring it is your enemy always. - Creationism (as it is described in the Christian bible for example) is clearly disproved by the fossils of dinosaurs and any number of other early creatures. The Bible says that humans and all other modern animals were created pretty much instantaneously in their present form - probably a few thousand years ago. Science has blown that theory into shreds. Why are there fossils at all? So the Creationists have retreated steadily into smaller and smaller claims in the hope that science cannot disprove them. The latest variation seems to be "Yes, OK, everything evolved...EXCEPT humans...who were placed here by magic". But that's gradually failing too - the reason you won't answer my question "When do YOU believe mankind came into existance?" is because whatever date you pick is problematic because if you pick a very old date - we have zero fossils of modern man at that age - which is impossible to explain - AND we have fossils of more recent (but less man-like) creatures that are more recent than that date. But, on the other hand, if you pick a date that's too recent, then you run the risk that science might find a modern human fossil dating back before then - which would handily disprove your theory. The truth is, no matter what date you pick, the FACT that man has been evolving very gradually means that we can always disprove what you say. So that's why you won't answer my question!

WHERES DEM BONES!! - in the museum where you can go take a look at them. You keep bringing this up over and over again like it was some triumphal claim of correctness - but the quite the reverse is the case. Whilst fossils are rare - we have plenty enough to document the slow evolution from proto-human to human. The important thing is "WHERE IS THE EVIDENCE THAT DISPROVES EVOLUTION" - not one single fossil has ever been found that disproves it. Every one we find slots neatly into the pattern we've established. Each one falls neatly into place. There is no countervailing evidence...not a shred. Point me to one actual FACT (not an absence of a fact - an actual tangiable THING) that disproves evolution. You don't have any because there aren't any. If we found a fossil T-Rex that dated to 1 million years ago - we'd be in deep shit. If we found a human fossil that dated back to 100 million years ago - we'd have a failed theory on our hands. But instead, every new bone that's dug up simply improves on our understanding - When did birds evolve from dinosaurs? Did dinosaurs have feathers? When did endothermy evolve? These are the questions - not "Does this whole thing work or not?"

I doubt you'll answer these (because you havn't answered a single one of the questions I've posed for you previously - despite my politely addressing every single point you make) - but I'll ask anyway:

1. Do you (as a creationist) believe in the idea that generations of organisms can change over time due to mutations in their inherited DNA? (I'm not just talking about man here - any creature or plant?)
2. Do you believe that's also true of humans?
3. Do you believe that if one creature out of a population has some genetic advantage (such as, for example, the ability to digest cows milk as an adult human in a primitive, agrarian society), that this individual is more likely to survive than the others in times of stress (such as a famine due to crop failure) ?"
4. At approximately what date did fully complete 'modern' man appear on the earth according to your theory? I don't need an exact date - plus or minus half a million years is plenty accurate.
5. If you picked a date less than (say) 20 million years ago: How do you explain the existance of fossils before that date?
6. If you picked a date more than 20 million years ago: How do you explain the lack of any human or human-like fossils between 20 million and 5 million years ago?

Honest, calm, on-topic and truthful answers to these questions please. Failure to answer will be regarded as evidence that you are talking nonsense!

SteveBaker 13:06, 2 August 2007 (UTC)

Hey, there, TripleBatteryLife, do yourself and us all a favor. Don't lecture us about science, and we won't lecture you about theology.

There are few things more pathetic than watching an envoy from a faith-based belief system, one who badly distrusts the scientific method and its results, try to use the scientific method in a twisted attempt to disprove its own results.

If you want to believe and have faith in your own hairy thunderer or cosmic muffin, please, do so. But if you want to use logic and the methods of science, you're going to have to learn how to use them properly, and learn why the currently-valid scientific theories are held to be valid. Once you do, you're not going to disprove any of them with a few glib arguments, because those theories have been painstakingly built up over hundreds of years by countless very careful thinkers, and they've already withstood (and been strenghthened by) the myriad counterarguments leveled against them by critics far more clever than you, me, or Steve Baker. If you want to use the methods of science, you're going to have to accept that life as we know it arose through evolution and natural selection, because that's what science today has proven. --Steve Summit (talk) 14:25, 2 August 2007 (UTC)

IS IT 24 hours yet? Am I going to be censored for the 6th time? Wow .. scientists who censor?? Just for forcing those who beleive in the GAP LEAP to accept that they do it on faith? Guess that really gets to them. Truth must be so emotional that they start to squash that which they don't understand! BOTH ARE TRUE! The facts support both! FYI: When you have a child in effect you are now a "creator". You say you believe "time dilation" but don't believe in a good spirit. FYI: "Some" religions believe that time went backwards for something like 14 minutes? I won't tell you where because I might be censored. TripleBatteryLife 15:25, 2 August 2007 (UTC)

It's hard to take people seriously when they fling loaded terms like "censorship" around meaninglessly.

We don't accept evolution based on blind faith; we accept it based on evidence and carefully-constructed rigorous arguments, evidence and arguments which have been presented to you numerous times and which you refuse to accept.

Please don't call it censorship when I suggest you drop the references to time travel. They're immaterial to the argument at hand and they're making you that much harder to take seriously. --Steve Summit (talk) 16:21, 2 August 2007 (UTC)

So you as a scientist are saying that some things are not theoreticallly possible. FYI: Even the defense dept uses Pschics as a tool as do police dept from time to time. I presume you think they are also fools? TripleBatteryLife 17:40, 2 August 2007 (UTC)

TripleBatteryLife is displaying the usual creationist thinking. See, the more transitional fossils found, the more "gaps" there are. If there's an extinct species A and a living species B, if an extinct species C is found to be a transitional fossil, creationists demand more transitions between A to C and B to C. It's ridiculous, honestly. No matter how many transitional fossils are found, creationists are never satisfied. 128.163.245.13 21:03, 2 August 2007 (UTC)

Yes - that was evident from his supposition that we believe that there is one single evolutionary step between "apes" and man. Nothing could be further from the truth - we believe there were hundreds or perhaps thousands of single-gene mutations between the common ancestor of chimps and humans - each change resulted in another step along the way. He thinks there is just one single step - and won't listen when we say otherwise. But that's not such a logical thing. If there was just one single step then he ought not to be demanding a million fossils spread throughout 4 million years - logically, he should be demanding just two fossils - one from the generation just before this sudden change and one from just afterwards. In effect, one fossil of Orrorin tugenensis and one of modern man - dated (let's say) 20 years apart. That would prove conclusively that the change from ape to man happened in one generation. However, that's not what science is claiming - and not what the evidence shows. Instead we see 40 or more separate fossils - each differing from the previous by a small amount...the kind of change that one gene could be responsible for. This fact is beautiful evidence for an evolutionary origin for mankind - and it fits exactly what we are saying. (That's not an accident - we're saying this BECAUSE that's what the fossils are telling us). However, this person does not listen - so he's repeatedly claiming that we scientists believe in time travel, that we think interplanetary travel is easy...all sorts of crazy stuff. In amongst all of those misconceptions is buried the one where he thinks we believe that evolution of man from ape happened in a single step. Why does he believe this? Who knows? I've asked some probing questions in an attempt to discover the root problem...and I don't get any answers. SteveBaker

<sigh> Firstly, I'm against censorship - as I think most scientists are. Free speech is the only way to avoid what the religious nuts did to Galileo Galilei. However, I note that you have not yet answered my questions to you...I really wish you'd take the time to do that. But Creationism isn't true - we're not censoring that view - we're just telling you it's indefensible...scientifically. You may feel free to boldly assert that this is a matter of religion and since God can to anything he wants, he can fake all of the evidence we'll ever find and therefore we can't prove a thing. However, as others have said - you are trying to argue SCIENTIFICALLY for Creationism - and now you have to live by the rules of evidence and proof. The whole debate about the teaching of creationism in schools is not that it shouldn't be taught - but that it shouldn't be taught IN A SCIENCE CLASS - because it's a matter of faith and religion, it needs to be taught in a religious instruction class.

The facts support both! - Which facts support creationism? I'm not aware of any.

FYI: When you have a child in effect you are now a "creator". - That's one meaning of the word. If by "Creationism" you mean "A belief that humans can have children" - then there is no argument. Evolution depends on the fact that animals have baby animals.

You say you believe "time dilation" but don't believe in a good spirit. - What?!? "Good spirit" - what do you mean by that - a bottle of 50 year old Scotch...that's a good spirit and I believe in that! If you mean to imply that time dilation implies a 'spirit world' or some such - then I don't understand how one implies the other at all. Time dilation is easily demonstrated. There are particles that decay very quickly when you make them in the lab - in a billionth of a second, they are gone. We have seen these same particles last for many seconds as they streak into our atmosphere from space at a substantial fraction of the speed of light. Time for those little particles has been 'dilated' - the speed of clocks on earth are running very quickly from their perspective - and our clocks tick by several whole seconds in the billionth of a second it takes them to decay! Time dilation in action! We also have experiments like flying two very precise atomic clocks around the world in jet aircraft heading in opposite directions - then very carefully compared the times on the clocks - and their times disagree to exactly the degree Einstein's math suggested it would. Time dilation (and relativity in general) is a very well proven law of physics.

FYI: "Some" religions believe that time went backwards for something like 14 minutes? - There are all sorts of nuts out there - I don't believe them either. Some people claim to believe in the flying spaghetti monster and the invisible pink unicorn (may Her hooves be forever unshod) - but that doesn't make them true. I won't tell you where because I might be censored. - Why on earth would we censor you for that?!

As for your last point - you are putting words into our mouths again. So you as a scientist are saying that some things are not theoreticallly possible. - We absolutely are saying that some things are not even theoretically possible. Travelling faster than the speed of light, making a perpetual motion machine, simultaneously measuring both the speed and mass of an electron to better than h-bar...all of those things are impossible - both in theory and in practice. There are lots of others.

Even the defense dept uses Pschics as a tool as do police dept from time to time....yes, there are a lot of nut-jobs in the police and defense department too! I've spent a large fraction of my life working with people in the Defense department - and whilst a lot of them are really smart people - they definitely have their share of crazies. But that's true of any group of people you care to name (including scientists) there will always be a handful of of people who's ideas are "off the chart". That's not such a bad thing - so long as they are prepared to debate the point calmly and rationally - listen and answer questions. The problem here is that you are doing neither. So - one more time - please answer my six questions above. Thanks! SteveBaker 21:13, 2 August 2007 (UTC)

Who discovered lathosterol?

Who was the first to discover/isolate lathosterol? What is the origin of the name "lathosterol" (What does "latho" stand for?) Tavilis 17:08, 27 July 2007 (UTC)

Dunno. But it looks like it was discovered around 1950: "...observations on the feeding of cholesterol to guinea pigs supported this concept (Glover, Glover & Morton, 1952). The work was done, however, before the discovery of lathosterol, which is difficult to separate from its isomer cholesterol. It has been shown that lathosterol can be converted into cholesterol in vivo (Cook, Kliman & Fieser, 1954)" [6] Rmhermen 03:47, 28 July 2007 (UTC)

In my Greek dictionary, the words beginning with lath (λαθ) all have to do with forgetting or secrecy, for whatever that's worth. —Tamfang 03:55, 30 July 2007 (UTC)

Magnetic North/South

It is a given that the north pole of a compass needle indicates the direction of magnetic North. Therefore it is North seeking. However if one is in the southern hemisphere, the same compass will still indicate North, is the north pole of the needle North seeking, or, as one would be closer to magnetic South, is the south pole of the needle South seeking?

Both. If you want to think of it that way, one end is always north-seeking and the other is always south-seeking. There's no reason to think only one pole can operate at a time.

If you want to understand it a little deeper, first realize that's there's no such thing as a magnetic pole (that we know of, at least: see magnetic monopole). There is only a magnetic field, and the compass needle aligns itself to that field. —Keenan Pepper 17:54, 27 July 2007 (UTC)

The entire compass needle is acted on by the magnetic field of the earth at all points, not just on one end of it. The N end of a compass needle points to a spot near (but quite a ways from) the Earth's north geographic pole, but which is actually a South magnetic pole. Edison 21:00, 27 July 2007 (UTC)

"...which is actually a South magnetic pole" is a matter of definition. Since there have been no geomagnetic reversals in recorded human history, surely, the North Magnetic Pole is the one nearest to the North Geographic Pole? - the same one pointed to by the lodestones and floating needles of ancient mariners who labelled the end that pointed north as North. Astronaut 16:05, 29 July 2007 (UTC)

Like magnetic poles repel each other, opposites attract; hence the magnetic pole in the northern hemisphere must be opposite to the point marked "N" on a compass. Physicists could have adopted the convention that the latter is a south magnetic pole, but didn't. —Tamfang 04:10, 30 July 2007 (UTC)

Newton's Third Law of Motion

I was reading Physics for Dummies and in the section about Newton's Third Law of Motion, it talked about how for a car to move, the road needs to exert as much force against the tires as the tires exert on the road. It goes on to say:

"So why doesn't the road move? After all, for every force on a body, there's an equal and opposite force, so the road feels some force, too. You accelerate...shouldn't the road accelerate in the opposite direction? Believe it or not, it does: Newton's law is in full effect. Your car pushes the earth, affecting the motion of the earth in just the tiniest amount. Given the fact that the earth is about 6,000,000,000,000,000,000,000 as massive as your car, however, any effects aren't too noticeable."

Is this actually true? -- Zealz 19:59, 27 July 2007 (UTC)

Yes. 151.152.101.44 20:00, 27 July 2007 (UTC)

Yes, If you stand on the ground it has to push up equally in order to keep you from falling through the same principle applies to moving objects that exert force onto the ground in order to move. If your car gets stuck in the mud that is because the ground can not exert enough force(through friction) on the tires to get your car moving.--64.40.88.131 20:16, 27 July 2007 (UTC)

Absolutely true, and fascinating! An other example I love is the following: when you jump up, the Earth provides the force necessary for you to rise, however, due to action and reaction, you exert the same force on the Earth, and it is actually pushed away from you. However, just as it says in the article, the Earth is 100,000,000,000,000,000,000,000 (10^23) times heavier than you, and while you jump up around a meter, the Earth moves such a small distance that it is simply not measurable... --Waldsen 04:01, 28 July 2007 (UTC)

As the old saying goes, the Earth weighs 150 pounds in my gravitational field. Bathroom scales work just as well upside down (except that you can't read the display). But note that your actions on the surface of the Earth can't cause any long-term deflection in its orbit, not even by a tiny bit, because they don't affect the center of mass of the Earth-you system. -- BenRG 00:47, 29 July 2007 (UTC)

You can point a flashlight directly into the sky. It will move the earth permanently.

dairy cow slaughter weight

About how much does a mature dairy cow weigh at slaughter? ike9898 21:07, 27 July 2007 (UTC)

There is more than one breed of cow that is used in dairying, so it would depend. [7] says a Jersey averages 900lb, but the range is wide, 800-1200lb. While many dairy cows are sent to slaughter beacause of age and falloff in production (which would imply a lower weight) many are slaughtered to regulate the supply of dairy products and thus prices so the average weight for a breed is probably not far off from the average weight of the cow when slaughtered. 161.222.160.8 23:08, 27 July 2007 (UTC)

It weighs exactly 1 whole stein. Duh. -- Azi Like a Fox 00:33, 29 July 2007 (UTC)

Blood glucose monitoring

A family member has recently started having to check his blood glucose level, with one of those electronic meters and monitoring strips. When he gets a new package of monitoring strips, he has to make sure that the meter and the monitoring strip have the same "code". What purpose does that code serve, and why do different packages of strips have different codes? Why can't the manufacturer make monitoring strips that all have the same codes? Corvus cornix 22:28, 27 July 2007 (UTC)

calibration perhaps (i.e. setting the correct zero point)? Flyguy649 ^talk _contribs 23:18, 27 July 2007 (UTC)

This patent abstract explains the calibration code concept in some detail. The Glucose_meter#Characteristics section also provides some explanation - hydnjo talk 02:25, 28 July 2007 (UTC)

Thanks to both of you. Corvus cornix 03:59, 28 July 2007 (UTC)

Back when cameras used film, the film came in a variety of "speeds." Setting the film speed into an automatic exposure camera correctly meant that it gave the right exposure. Manufacturing variation in the sensitivity of the test strips means that without the coding the inaccuracy would be greater than when the strips are correctly coded into the tester. Ideally the manufacturer would have quality control such that coding is unnecessary, or the strips would tell the meter their codes automatically, like some modern film cameras can automatically sense the film speed. Edison 05:52, 28 July 2007 (UTC)

And this patent extract describes the machine readable calibration code that Edison mentions above. Interestingly, the abstract also gives some clues as to why the codes are necessary in the first place. - hydnjo talk 10:31, 28 July 2007 (UTC)

It still boils down to the inability of the manufacturers to adequately control the strip manufacture so that the strips all work the same in the meter. An alternative would be to increase the cost by rejecting those which fall outside a narrow tolerance band. If a user happens to switch vials of the test strips and the coding is not for the present vial, the results can be off substantially more than if there were one tolerance band for the strips and the manufacturing was calibrated to conform. Coding allows for poor quality control in the mass production of the strips. When they apparently charge 75 cents or a dollar for some of the strips, it seems pretty obvious to spend a fraction of a cent and add a calibration mark on the strip to be resd by the meter. Edison 16:35, 28 July 2007 (UTC)

Agreed but life is full of compromise. The current state of test strip manufacturing capability, even with calibration codes, still has a +/- 10 to 15% error band when compared to a lab analysis of blood glucose in a blood sample. - hydnjo talk 17:28, 28 July 2007 (UTC)

The Equator

I encountered a curiosity, and it seems appropriate as a Science question. Take the entire population of the earth at the present moment. Have each and every person stand side by side. They are standing on the equator and, thus, forming a "line of people" (a circle) that circumnavigates the globe (at the equator). The question is: how many times will that line "wrap around" the globe, if you need to have every person participate? (Assume that people can "stand" along every portion of the equator -- including oceans, mountains, etc.) Thanks. (JosephASpadaro 23:02, 27 July 2007 (UTC))

I figured the average shoulder breadth to be 2ft. At a population of 6 billion that is 12 billion feet of shoulder. The equator is 24901.5 mi long, which is 131,479,920ft. Divide the first by the second and I get 91.26 times. Growing all the time though. 161.222.160.8 23:17, 27 July 2007 (UTC)

6 billion! That is so 7 years ago! While I've been typing this message, the "world population clock" estimate at census.gov has ticked past 6,608,000,000. Which means that if 161's other numbers were precisely accurate, the answer to Joseph's question would be 100.517+. Of course, "about 100" is really about as accurate as can reasonably be said. --Anonymous, July 28, 2007, 02:57 (UTC).

If they would stand breast to back and assuming they are on average 20 cm 'deep', that would be a ribbon of 20 m. On a half circumference of roughly 20,000 km that would mean we occupy only one millionth of the surface of the Earth (of course that is not entirely correct because the Earth isn't a cylinder, but it's only meant as a rough indication). And assuming an average height of 2 m, on a thickness of the atmosphere of 100 km that's 1/50,000 in height. Combined, we occupy only 1/50,000,000,000 (one 50 billionth) of the atmosphere. And the atmosphere is just a tiny layer around the Earth, which has a radius of 6,000 km, so that's 1/60th, so we occupy 1/3,000,000,000,000 (one 3 trillionth) of the Earth. And that's for all 6 billion (+) of us, which gives you an idea of how puny we are as individuals, compared to the Earth - 1/20,000,000,000,000,000,000,000. I won't extend these calculations into space. :) DirkvdM 05:51, 28 July 2007 (UTC)

20 cm x 6,000,000,000 = 20 m (2,000 cm)? What? Skittle 12:44, 29 July 2007 (UTC)

Clarifying what I believe DirkvdM means with the 20cm estimate: In the original calculations, we have people standing shoulder to shoulder, and this wraps 100 times. That means, everybody is standing in a rank of 100 people, breast to back, stretching 20m / 2 = 10m on each side of the equator./85.194.44.18 18:55, 29 July 2007 (UTC)

Ah, that makes more sense. It seemed a little odd. Skittle 23:15, 29 July 2007 (UTC)

Average height 2m? What world do you live in? :-P N.B. As with a recent question re: human weight (mass), a lot of people seem to be forgetting that many of the 6.8 billion or whatever are children and many are also in developing countries in relatively poor health so the averages are probably an overestimate Nil Einne 15:49, 28 July 2007 (UTC)

Like I said, it was meant as a rough indication. DirkvdM 07:58, 29 July 2007 (UTC)

20cm x 6,600,000,000 = about 33 times round the equator.

Incidentally, I suggest taking a peek at John Brunner's novel Stand on Zanzibar. Astronaut 16:20, 29 July 2007 (UTC)

I think a much more satisfying project would be to convince the population of the United States (~ 300,000,000) to stand on each other's shoulders (~ 1.5 m) and thereby be 450,000 km tall, which is high enough to touch the Moon. --TotoBaggins 14:15, 30 July 2007 (UTC)

might work if we built it from the moon down --froth^t 14:54, 30 July 2007 (UTC)

July 28

Force particles

When a force particle collides with another particle, it changes the velocity of the other particle, right? If so, there must be a constant stream of force particles coming out of an object that makes that force (such as photons out of electrons and gravitons out of everything). If each force particle has energy, where is the energy coming from? Also, are gravitons effected by gravity the same way everything else is? Where does it go when it hits the other object? Is there anything I can read that I don't have to pay for that talks about that stuff? — Daniel 00:21, 28 July 2007 (UTC)

I don't know what you've been reading, but unless I'm badly mistaken, there's no such thing as a "force particle", and we've never detected or even proven the existence of the mythical graviton, either. So there really aren't any answers to your questions. —Steve Summit (talk) 01:06, 28 July 2007 (UTC)

The theory of gravitons is basically just theoretical (read: made up) at this point.. they thought "we discovered a particle for every other force so lets make one up for gravity". Very little is even guessed about them at this point- come back when we discover a unified field theory. IMHO certainly there's a better way of describing gravity than infinite numbers of noninteracting particles flooding every point of the universe. --froth^t 01:16, 28 July 2007 (UTC)

The proper term is messenger particle or force carrier. In my experience, all explanations of their function that don't invoke quantum gibberish, yet more quantum gibberish, or the pinnacle of quantum gibberish are all actually incorrect. So unless you plan on devoting several years of higher education to the field, it is hard to develop an actual understanding. It's not your fault, though, it's the fault of quantum for being such complete and utter gibberish. Someguy1221 01:27, 28 July 2007 (UTC)

You're right that force-carrying particles can carry energy and change the velocity of other particles. You can draw Feynman diagrams that show exactly that happening. However, there is not a constant stream of photons carrying energy away from every electron. Instead, there's a photon field that has some properties in common with the electric field and magnetic field in Maxwell's equations, some properties in common with a particle in ordinary quantum mechanics, and some properties that are new to quantum field theory. If the electron is minding its own business, not accelerating or interacting with anything else, then the photon field doesn't carry away any energy. If it gets accelerated, it will radiate some energy in photons. If it passes by some other particle, it may scatter and lose some energy through interactions mediated by photons. And yes, we expect that gravitons should also interact with gravity like everything else does. --Reuben 01:42, 28 July 2007 (UTC)

Why does the electron need to pass by something? If there are two electrons, no matter how far apart they are they repel each other. Is this just an inaccuracy of classic physics? Does an electromagnetic wave have a chance of collapsing so the photon that it is has never been emitted? Is it impossible for an object to emit a force carrier so it never hits anything. If gravitons are effected by gravity, wouldn't it be impossible for gravity to escape a black hole? I guess in that case the gravitons couldn't actually hit each other, but if two bodies emit gravitons at each other, would the gravitons from each body increase the energy of the gravitons from the other body? — Daniel 02:01, 28 July 2007 (UTC)

That's still true, but it's not at all simple to understand in terms of quantum field theory. You have to describe it in terms of the photon fields, or very very many (in fact, an indeterminate number of) virtual photons, which don't have the same properties as "real" photons. Believe it or not, the question of whether or not it's possible to emit a photon that never gets absorbed is a famous and subtle question! I would have to search for more information about it. I'm not sure it's settled on a fundamental level what the answer is. As for gravitons near a black hole, our models break down. Fortunately, people have found ways to calculate most of what we need to know based on considering what happens just outside the event horizon. So it may be that black holes have exactly the gravity you expect, even if no gravitons can actually get out. It's likely to be very very difficult to understand any measurable gravitational phenomena in terms of individual gravitons. You'd have to go to graviton fields, or (again, indeterminately many) virtual gravitons. And these calculations will not be easy. --Reuben 04:22, 28 July 2007 (UTC)

If I'm understanding the OP correctly, that's a good question, and one which caused Einstein and others to come up with the idea that gravitational, electromagnetic, etc. fields have to change the "geometry of space", so that they can affect the movement of other objects without having to continually supply energy from somewhere. Of course, this unfortunately reminds me of the original theory of colloids, where scientists couldn't figure out how enzymes would give a glass of water the ability to digest protein, for instance, so they decided that dissolving the enzyme in the water somehow changed the structure of the water so as to make it digest proteins.Gzuckier 17:27, 30 July 2007 (UTC)

Brain Memory

Memory is stored in brain cells but ? In What forms is that memory stored ?

Memory isn't stored. Experiences are stored and that's what we call memory. So the question is then "how does memory work", and I don't think there is anything near a conclusive answer to that. At the cellular level, very roughly speaking, neurons receive signals from other neurons and send signals to other neurons in response. How strong the signals they send are depends on the strength of the signals they receive and the history of received signals. That last bit is the memory bit. How those actions by individual neurons combine to form memories at a higher level is where it gets trickier. DirkvdM 05:28, 28 July 2007 (UTC)

At the neuron level, memory is stored via synaptic plasticity. See Long-term potentiation and Hebbian theory. MrRedact 05:38, 28 July 2007 (UTC)

For bonus points, how many petabytes of information can a human brain hold? Including corruption and fragmentation over a lifetime, of course --L^ie! 05:43, 28 July 2007 (UTC)

It’s hard to give an accurate answer to the "bonus" question, because a brain and a computer store information very differently. But as a rough approximation, the information content in a brain could be viewed as very crudely being similar to the information content in a matrix, where the matrix indices specify presynaptic and postsynaptic neurons, and the non-zero matrix elements specify the efficacy of a synapse connecting the two neurons. With one byte to specify the efficacy of a synapse, and 5 bytes to specify the index of a neuron, an efficient sparse matrix representation of the matrix would require about 6 bytes per synapse. If a brain has about 10¹⁵ synapses (I’ve seen estimates between 10¹⁴ and 10¹⁶), that would correspond to the brain holding about 6 petabytes of information. However, that number is a very rough estimate. I think some neurobiologists would argue that that number should be considerably higher, because there’s a lot of weird stuff that goes on at the neuron level that doesn’t map well to an artificial neural network model of the brain. And some AI researchers would argue that that number should be much lower, because it’s possible to represent some of the information that we use our brains to store much more efficiently than with a neural network. MrRedact 07:00, 28 July 2007 (UTC)

I have a suspicion that memory, as distinct from the processes that govern reason and handle inputs and outputs, is actually quite limited. How much independent information can a human actually recall? Is it more or less than the amount of information written in Wikipedia (for example)? Wikipedia has a few hundred gigabytes. If one lives 70 years, you could devote 20 minutes per article to learn all of Wikipedia's content (ignoring details like sleep and food). If we limit the discussion to just the facts and information that humans can recall, then I would not be surprised if that could be compressed into a terabyte or so. This excludes the highly complex operational hardware and software that allows us to process this information and sensory input into that thing we call consciousness. Dragons flight 08:18, 28 July 2007 (UTC)

I could question whether it make any sense to limit the discussion to just the 'facts and information'. Humans appear to remember a very large variety of sensory experiences in a large variety of detail. A lot of that may not even be easily accessible to the human but is clearly stored since it may be remembered if a certain trigger is present. Bear in mind most of wikipedia is text. If wikipedia's content was all in video form for example, the data storage requirements would be vastly different. In the end, I don't think any comparison makes sense. You simply can't talk about the human memory in bytes since it does not work in bytes. Nil Einne 15:46, 28 July 2007 (UTC)

Any information can be measured in bytes. If you take the negation of the binary logarithm of the probability of a certain state, that is the information of that state. For example, if there is a one in a million probability of me winning the lottery, the information that I didn't is -lg0.999999=0.00000144269576 bits. The information that I won would be 19.9315686 bits. If the information was a bit fuzzy, and it only said there was a 50% chance of me winning, that would be one less bit of information. The actual act of measuring a person's memory like this is incredibly difficult, but it still theoretically can be measured in bits. Changing this to bytes is trivial. It should be noted that information stored on your computer rarely if ever has perfect compression, and the amount of memory used is more than you'd calculate. — Daniel 20:27, 28 July 2007 (UTC)

I disagree although I admit I don't understand most of the mathematics of what you're talking about or informationa theory very well. I don't think you can give any numerical figure to the 'information' that the human brain stores precisely because it does not work like that. Human memory is closer to analog then digital, although it's neither AND both IMHO. Also, I don't think it makes that much sense to talk about compression let alone perfect compression when it comes to human memory. Human memory isn't compressed so to speak, at least not in the way we think of when it comes to digital compression. The level of detail stored of course varies. (However as I mentioned above, it's important to consider that even determing the level of detail is difficult as we often 'store' more then we normally remember). I'm not sure but I think you may have missed the main point I was trying to make. It seems to me you're still just thinking of the human memory as pure information which IMHO is too simplistic and doesn't make sense. even if to some extent, you can argue that all memory is basically information. Perhaps there are things that I don't understand but really, I wouldn't trust any answer coming from someone without a detailed knowledge of information theory and the extremely complicated human neural system (which we are only just beginning to understand). Most answers I've read (in general, not here) usually seem to be coming from one or the other. One answer I came across was this one [8] which is interesting more in how poor the figures are. While the Landauer work is interesting (and the experiments analysed described only in minimal detail so perhaps it's better then what it appears although I'm somewhat doubtful you can come to any meaningful conclusion about how much someone remembers about a picture from a true & false/MCQ test), it appears to be highly flawed in that it was only really only looking at very simplistic memory and very simplistic information. Nil Einne 01:49, 30 July 2007 (UTC)

Yeah; the classical example is the grandmother cell where the memory of your grandmother was stored; if anything happened to it, people would ask you "who's your father's mother?" and you'd be stumped. No, the mind doesn't store things that way, on any level except perhaps the most simple. Gzuckier 17:30, 30 July 2007 (UTC)

chicken skin

I started having chicken skin on my neck. I wonder how i got this. can be from eating chicken? what must i do to make it disappear. Thank you for any answer you may provide. —The preceding unsigned comment was added by 124.104.136.216 (talk • contribs) 12:12, 28 July 2007 – Please sign your posts!

Whatever it is, it is definitely not from eating chicken. My guess is that it is a rash or chafing, but I'm not a doctor and not qualified to give medical advice. 72.148.109.119 13:05, 28 July 2007 (UTC)

Please take the time to read the guidelines above. Wikipedians don't give medical advice. Sorry Nil Einne 15:40, 28 July 2007 (UTC)

You may be referring to Keratosis pilaris. You may also want to see a dermatologist. Someguy1221 21:28, 28 July 2007 (UTC)

Or pseudofolliculitis barbae, since you mention it is on the neck. This is most likely if you are a male of African descent. If this is the case, it should go away as your beard grows out. To prevent it, just avoid shaving so close so hairs don't get ingrown. HYENASTE 01:23, 29 July 2007 (UTC)

If you get chicken skin on your neck from eating chicken, you need to use your napkin. Gzuckier 17:31, 30 July 2007 (UTC)

Or aim a little higher. Capuchin 10:32, 1 August 2007 (UTC)

does photon move in straight line ?

i've always taught that photon's move in straight line . but i've also learnt that sometimes photon is of dual nature . sometimes they move in wave form . but the front of a wave always changes direction so the path can't be said straight . enlighten me if i'm wrong .

One way I've seen it nicely explained... The photon is moving in a straight line from its point of view. It may be moving like a wave from your point of view. -- Kainaw^(what?) 13:56, 28 July 2007 (UTC)

Consider this as an analogy. Take a boat trip directly across a harbour from one dock to another. You regard yourself as travelling in a straight line across the water. But the water has a bit of chop on it creating small waves that move the boat, and therefore you, up and down as you travel in your straight line path from dock to dock. This is like the photons moving as a wave front. There's a couple of other things to consider. The wave–particle duality is a model that helps us understand the behaviour of things like light, not an exact description of reality. And, light does not always travel in straight lines, it can be bent by extremely large masses; see for example gravitational lens. --jjron 14:40, 28 July 2007 (UTC)

Electromagnetic waves don't wiggle back and forth as they move! The field strength oscillates perpendicular to the motion, but that's not a spatial displacement.

In quantum field theory, the only place where the word has a well-defined meaning, a photon is a quantum of energy in the electromagnetic portion of the overall quantum field. If you have two liters of water in a container, you can't say which parts of the water correspond to individual liters, and it's the same with two photons in the electromagnetic field. Photons are quanta of waves, definitely not particles in the ordinary English sense of the word. The reason photons often seem to move in straight lines is the same reason classical geometric optics is a valid approximation. -- BenRG 16:01, 28 July 2007 (UTC)

The photon is itself like a wave, it is not moving along a wave. --24.147.86.187 21:21, 28 July 2007 (UTC)

Photons do not have to travel in a straight line, it's that is the more likely route. They are subject to the uncertainty principle where you cannot measure the momentum (say direction as the speed is known) and its location precisely at the same time. GB 22:16, 28 July 2007 (UTC)

^{Fixed your uncertainty principle wikilink — Matt Eason (Talk &#149; Contribs) 23:00, 28 July 2007 (UTC)}

Artificial lung

Why can't a machine similar to a dialysis machine remove blood from the body, add oxygen, remove carbon dioxide, then return the blood to the body ? Such an artificial lung could replace normal lungs when they are damaged by smoke inhalation or disease, or recovering from surgery. StuRat 20:33, 28 July 2007 (UTC)

Such a machine exists - see Oxygenator and Heparin-coated blood oxygenator. -- Finlay McWalter | Talk 20:52, 28 July 2007 (UTC)

See ECMO for an even more advanced version. alteripse 02:42, 29 July 2007 (UTC)

There is such a thing as a heart-lung machine, but this is not used unless the patient is undergoing heart surgery or a heart transplant.

Lightning

Are there any warning signs (say a few seconds in advance) that allow you to tell that you are going to get hit by lightning? And if you did know, would there be anything you could to to prevent it from happening? 71.38.188.212 20:36, 28 July 2007 (UTC)

This NOAA page says your hair might stand on end, and suggests a crouch that might minimise the danger of your being struck. -- Finlay McWalter | Talk 20:49, 28 July 2007 (UTC)

Lower your highest point as much as possible and keep contact with the surface to a minimum (lightning travels through the ground after it has struck). So squat. Wearing the right kind of soles on your shoes might also help. So don't touch the ground with your fingers (to keep balance, for example). DirkvdM 08:20, 29 July 2007 (UTC)

The advice I heard was to squat with both feet together. Wrap your arms round your knees and tuck your head in as much as possible. I'm not so sure though - wouldn't lying as flat as possible be better? Astronaut 16:35, 29 July 2007 (UTC)

The concern with lying flat on the ground is that lightning current can pass through the ground (for example, lightning strikes a nearby tree and disperses throughout the surrounding ground). If YOU are lying on the ground, then you, as a bag of mostly salty water may provide a better conduction path across that five or six feet of ground than the soil does. For this reason, the advice is to crouch with your feet together so that you're less likely to form part of the current traversing the ground.

Atlant 00:24, 30 July 2007 (UTC)

Another way to look at that is that at the precise point where the lightning strikes (maybe a centimeter across) - the voltage at the ground is a bazillion volts - but 10 meters or so away, it's grounded (so pretty much zero volts) - the number of volts per meter of ground is insanely high. When you touch more than one point on the ground - the voltage between those two points on the ground is probably going to flow though your body (which is nicely conductive) rather than through the ground (which probably isn't). If your feet or hands were touching the ground at points one meter apart - then you'd be taking 1/10th of the 10 meters of voltage difference through your body. If you could get your points of contact within 10cm of each other - then you only take 1/100th of the voltage. The smaller the area you cover - the less of a belt you get - hence the advice to keep your feet together. You also want to avoid touching the ground with your head or your hands because a shock across your heart or through your brain is much more likely to kill you than one that can take a short cut without going that way. In the canonical 'stuck out on a golf course' scenario, I'd be tempted to place a golfclub on the ground and to stand on that - on the grounds that a nice metal shaft would probably conduct the electricity directly rather than it going through my body at all. But then given how little time you have to think about it and act - all of this advice is probably entirely pointless. SteveBaker 04:23, 30 July 2007 (UTC)

?????

I know this seems impossible but science taught us to exclude the word impossible from our dictionary ..... anyway the use of nanotechnology to upgrade parts of a human, such as memory, strength, iq ..... etc Can this be real ??????

It's hard to say what future technology will bring, and what will prove to be very difficult or entirely impossible. If you look at science fiction films from the 1950s people can fly and zap one another with ray guns, but still have big fat curvy tv sets with no remote control. So who knows. You might want to read Technological singularity. -- Finlay McWalter | Talk 22:45, 28 July 2007 (UTC)

As one might imagine, the most amazing-seeming technologies that will become available in the future are going to be things no one ever thought of. Before the science of genetics was well understood, it was likely inconceivable to most people that organisms could be "engineered" to express a desired trait. And before E=mc², it was likely equally inconceivable that a large ship could be powered for years with only a baseball sized volume of fuel. 151.152.101.44 23:58, 28 July 2007 (UTC)

It is impossible for the laws of physics to be broken. If they could be they wouldn't be the laws of physics. I suppose it's possible that the universe is totally indeterministic, and nothing is totally impossible, but you couldn't get certain things to happen consistently. — Daniel 03:21, 29 July 2007 (UTC)

Daniel, you obviously haven't read the latest research in improbability. Someguy1221 10:11, 29 July 2007 (UTC)

On a serious note, though, there are some things that physics would simply prohibit. I believe the more accurate phrase would be, "the appearance of anything is possible." Someguy1221 10:11, 29 July 2007 (UTC)

I strongly disagree with our OP here "science taught us to exclude the word impossible from our dictionary" - certainly not! Quite the opposite in fact - put the word "impossible" back into your dictionary and apply it liberally where the science indicates that it's appropriate! There are certainly well-established laws of physics that make some classes of thing impossible. Travelling faster than light is impossible, perpetual motion machines are impossible, knowing both the position and speed of a particle to more than a certain precision is impossible.

Then we have "I know this seems impossible" when referring to using nanotech to improve human performance. That doesn't seem impossible at all. There are a lot of people working in the field of nanotechnology - and lots of people working on human-implantable-technology - and if their work comes to fruition, we'll see things that are as much like magic to use today as Wikipedia would have seemed to Newton.

But why invoke nanotechnology here? It seems to me that the work to interface fairly normal computer electronics into the nervous system is coming along rather quickly. I don't think it's at all far-fetched that one could have a large implanted memory subsystem with (say) enough capacity to hold everything that's currently on the Internet - plus the ability to record everything you've ever seen, heard, touched or smelled in your life from the point of implantation onwards. Having 100% perfect recall of all of those things would certainly give the impression of superhuman abilities - with no nanotech required. Increasing IQ is a little more controversial - but someone with the ability to do lightning-fast mental arithmetic, to be able to speak every language, recite every poem, play, film script or song by heart (because they have a calculator, a translator and the library of congress embedded in their brain) would certainly seem pretty smart to us. SteveBaker 13:14, 29 July 2007 (UTC)

100% perfect recall with a memory storage may however be something like hypnopædia (sleep teaching), where phrases can be memorized but there is no comprehension. As for upgrading parts of a human, I read somewhere about a new technology that enables blind people to "see" by use of a device that you stick on your tongue. This was 4 or 5 years ago too, so I don't see why human "enhancements" are not possible.--GTPoompt(talk) 12:42, 30 July 2007 (UTC)

FM signals

Ok I am 12 years old so I know barely anything about radios and how humans cross between them so here is my question.

So I was practicing guitar right, and then when I was done I took the cord out of my guitar but didnt turn the amp off. I noticed that when I touched different objects with the tip of the cord some objects would make buzzing sounds (out of my guitar amp) so then I realised that the sounds only came when I touched something metal or my body. Then I was testing different parts of my bady when I put it on my hand. Then the amp was buzzing a bit but I could hear some sounds changing. Then I swore I heard some english words and knew it was a radio. I startewd walking around my room with the cord to my hand (trying to get a good signal) when all of a sudden the rock station 103.9 The Hawk* came on and I could hear people having a conversation in somewhat fuzzy sounds (like when you are leaving a town and the station fades out but you can still understand everything). So my question is obviously, How is this possible?!?

• 103.9 The Hawk is a London ontario station and I do live in London Ontarioand with a radio get a clear signal

I'm not sure of what causes it but I understand people have picked up radio signals with their metal-fillings. The signal itself carries power which is how those old-radios that kids used to build (crystal radio) worked. It my be worth looking at radio waves radio and articles linking from this. I remember reading somewhere that people have inadvertently picked up old radio broadcasts from the 40s/50s/60s - not sure if it is true though. I expect your setup is because the cord is acting as an antenna and the amp as a speaker (presuming the amp has a speaker built in). Similarly it's my understanding the individual's mouth acts as the speaker in the somewhat odd radio from dental-work situation. ny156uk 23:16, 28 July 2007 (UTC)

If anyone actually picked up radio broadcasts from the 40s/50s/60s it's because they picked them up in the 40s/50s/60s, or someone rebroadcast them. Radio signals don't remain detectable after 40 years of bouncing around. Unless, of course, you're 40 light years away, and you're aiming a football-stadium sized radio telescope at the Earth. 151.152.101.44 23:48, 28 July 2007 (UTC)

(this is made by the person who started it) But when the metal part of the guitar/amp cord (with the other metal part in the amp and it's turned on) is not touching my hand it just makes a loud buzzing noise and only when I poke my hand with it does it tune in.

Radios work by having a resonant circuit that can be adjusted to pick up only a particular carrier frequency. Such circuits are actually quite simple in design and depend on details like the resistance in the circuit. It is concievable that by "poking" it, you alter the current loop, so that you are turning into a particular resonance corresponding to 103.9. Dragons flight 10:23, 29 July 2007 (UTC)

I"m a little surprised that you'd pick up an FM station that way - but AM radio is pretty easy to pick up accidentally in wires that happen to be the right length to act as an antenna. By touching the end of your guitar cord to different objects, you are changing the effective length of the antenna and thereby 'tuning in' different frequencies. If you happen to hit the exact frequency of a reasonably powerful AM radio station, then you'd certainly be able to pick out the audio given a sufficiently powerful guitar amp. But FM radio doesn't work like that - and I don't see how you'd get it that way. Are you 100% certain it was an FM station that you picked up? SteveBaker 12:57, 29 July 2007 (UTC)

There are two ways you could receive an FM station using a guitar amp:

1. The FM station simulcasts on an AM station; it's very easy to receive AM radio using devices that aren't really intended as radio receivers, especially if we're talking about most-powerful AM station in your neighborhood.
2. Slope detection allows an amplitude-sensitive detector to receive an FM signal. But that's asking for a pretty odd set of circumstances to come together in your guitar amp and cable.

Atlant 00:33, 30 July 2007 (UTC)

Well, an FM station broadcasting on the AM band is what I would call "An AM Station" - but then I'm a traditionalist! For slope detection to work, the AM reciever would have to be very finely tuned such that as the frequency moves around due to modulation, the amplitude of the reception drops off rather rapidly as a function of frequency. That's totally not going to be the case with a guitar cord touching something metallic because the irregular shape of the final antenna would have a pretty flat frequency response. So I think we're talking about a radio station that maybe broadcasts on both FM and AM at the same time. SteveBaker 04:10, 30 July 2007 (UTC)

When you dismiss slope detection, you're ignoring the possibility of resonance.

Atlant 11:55, 30 July 2007 (UTC)

Unshielded cables, like those used for guitars, can pick up all kinds of electromagnetic interference, like radio signals. This is why most microphones, and lots of other audio gear, use shielded cables (often with XLR connectors) and a balanced audio system, to keep outside signal interference to a minimum. Pfly 05:18, 30 July 2007 (UTC)

Was the guitar amp on the distortion channel? — Omegatron 23:35, 30 July 2007 (UTC)

Animals eating their waste

Why is it that some animals, including humans eat or lick their waste? (vomit, urine, or shit) For some reason, I've only noticed it in mammals.

Ive seen videos of dogs licking their vomit. Chimps drinking their pee. Gorillas eating vomit AND their shit. And we all know theres humans that enjoy drinking urine. And humans that enjoy being pissed on, or shitted on for sexual excitement.

Waste has a lot of bacteria and eating it can be fatal, so why do animals do it? Is it another one of those weird rare things that people just do? Were supposed to think it's nasty (im thinking because of psychological evolution), so is it another one of those rare traits that some animals in a species have? PitchBlack 23:41, 28 July 2007 (UTC)

Animals will eat vomit as the food is not fully digested, so they eat it again as it still has nutritional value. The same is sometimes also applicable to excrement if not fully digested, they give it a second go. A puppy will somethimes learn to eat excrement as a behaviour - when you clear it away it considers you to be taking something belonging to it. What better way to stop you than scoffing it back down again? Lanfear's Bane

Animal waste is a rich source of pheromones. Some animals will lick it either to aid detection of the chemical cue of another animal, or to spread their own cues around. Rockpocket 00:26, 29 July 2007 (UTC)

On a side note: one of my terriers constantly tries to disguise his scent by rolling in other animals excrement, he is always a pleasure to take walking... Lanfear's Bane

See Coprophagia -Arch dude 01:01, 29 July 2007 (UTC)

Ha, thanks for the info. Makes sense. But none of you mentioned humans. I'm pretty sure humans dont eat their crap because it still has "nutritional value", they GOTTA have some poptart lying around somewhere. But anyway, is it possible that some humans got it as a result of evolution? Somehow us getting it from past mammals? PitchBlack 05:12, 29 July 2007 (UTC)

Why do humans have any kinks? Its a type of paraphilia. Rockpocket 07:27, 29 July 2007 (UTC)

Most of it is probably caused by either folk medicine or lore, or fetishism. Taken from one of my Bathroom Readers, some of the following inventive usages:

• India - The Vedas call urine a nectar of the gods and fountain of youth.
• Rome - The emperor places a tax on the commercial sale of urine. People with ulcers and cancers think ingesting urine will cure them, and showering in urine is a popular practice (Gives new meaning to the term golden shower, huh?)
• China - Believed to make medicinal herb potions more potent.
• Egypt - "Urine is drunk down, rubbed on, bathed in, and stared at". Also used as an early form of pregnancy test.
• Germany - Urine boiled lightly with honey is popular as an eye curative (? no idea what they mean there)
• England - After overindulging, people rub their urine on themselves immediately after they produce it, to avoid "the shakes". Gargling urine with saffron is used to avoid throat inflammation.

So uh, now you know, I suppose. They also make points afterwards such as urine not being toxis, it being 95% water and 2.5% urea, and 2.5% minerals, salts, hormones and enzymes, and that urea is poisonous in large amount, but "the small portions present in urea actually purify the body, clear up excess mucus, and purify the skin, which is why it's a main ingredient in women's cosmetics", that urine is sterile, and that it contains antibodies that can help to ward of diseases. They know way too much, if you ask me --L^ie! 07:30, 29 July 2007 (UTC)

Urine isn't necessarily sterile, or so someone here once pointed out to me. But it is less likely to carry diseases than feces. An important point here, though, is that if one consumes one's own urine or feces, any diseases in it will come from oneself, so there is no added infection (in some cases it might aggravate it, though, not sure about that). And if excrement from other animals contains a disease, it's not likely to be a disease one can get oneself. It's the excrement of others of one's own species that is most dangerous. Which is why it is safe to use cow dung to fertilise foodcrops, but not human droppings. (Notice how I nicely avoided the word 'shit' :) - damn, used it after all ... ). DirkvdM 08:14, 29 July 2007 (UTC)

Yeah, excuse me for not thinking of another word at the time. I was thinking too quickly and I couldnt think of anything else.

E.coli is safe in our bodies, to decompose the waste I guess. But it's dangerous to eat. So how would you explain that? PitchBlack 08:44, 29 July 2007 (UTC)

Escherichia coli isn't always safe in our bodies: it depends on where it is (normal flora of gastrointestinal tract as opposed to causing a urinary tract infection), and the occurence of disease also depends on which strain it is. Recurring dreams 12:11, 29 July 2007 (UTC)

Well, I think that was PitchBlack's point. You can't assume something is safe just because it comes from you (DirkvdM's opinion). We're pressing close to medical advice ("Can I drink my own pee?"), so I think it's a good time to point out that both urine and excrement can be dangerous to consume, even if they are your own. Matt Deres 01:54, 30 July 2007 (UTC)

There is an abnormal condition known as Coprophagia that exists in many animals (even humans) in which they desire to consume there own feces.Mrdeath5493 17:04, 29 July 2007 (UTC)

Rabbits (and maybe similar animals?) eat their own poop because that's how they "chew their cud". Unlike cows, which have evolved a special place to store the grass they eat to let it ferment, then burp it back up to chew and swallow for keeps, rabbits have to do the double pass thing. (I'm not sure if the poop they eat is different from their regular poop, never watched that closely).

According to The Private Life of the Rabbit, the two types of droppings are indeed different. We may have information in rabbit, but I'd have to check. Skittle 20:35, 30 July 2007 (UTC)

On another note, many animals eat cat poop, whether house cat or lion; the cat digestive system is so inefficient, and their diet so high-protein, that their poop ends up being quite high in protein itself. Gzuckier 17:36, 30 July 2007 (UTC)

Some dogs also seem to have a particular fancy for horse faeces, presumably due to the efficiency of the equine digestive system leaving useful nutrients behind. Martinp23 20:43, 30 July 2007 (UTC)

Oddly enough, I've just noticed that this question was one of the very first questions asked on the Reference Desk, ever. See this archived version. —Steve Summit (talk) 15:42, 4 August 2007 (UTC)

July 29

solar flares

I guess solar flares don't create a sound/sound waves (i.e. no medium), is that correct? ````

Correct. While there would certainly be vibrations within the sun itself, which you could call sound if you wanted to, no sound eminates from the sun, in the form of solar flares or otherwise. Someguy1221 00:55, 29 July 2007 (UTC)

Considering that a absolute vacuum does not exist, not even in deep space, there could in theory be sound. An affected particle is bound to bump into another one at some point. But the sound would be extremely faint (negligible, I suppose). That is, if one can call that sound. Sound is a wave, which is more than just moving particles, and a wave needs enough density. At which density would sound become possible then? DirkvdM 08:04, 29 July 2007 (UTC)

For any combination of density and temperature, different amplitudes and frequencies would have different thresholds of detectability. That threshold would be wherever the sonic vibrations become detectable over random motions (though for sufficiently low densities, it would always be beyond our ability to detect). Where that threshold is, is dependent on our technology. There is probably also a fundamental threshold based on the random motions (I'm deliberately avoiding the word "noise" due to the confusion it would create). Now, how to actually calculate either the fundamental threshold or the tech-dependent one, I have absolutely no idea. Someguy1221 10:08, 29 July 2007 (UTC)

Shock waves exist in space and they are detectable. See Bow Shock.

You might check these links:

• http://www-pw.physics.uiowa.edu/space-audio/
• http://soi.stanford.edu/results/sounds.html
• http://quake.stanford.edu/~sasha/SOUNDS/sounds.html

SteveBaker 12:51, 29 July 2007 (UTC)

My fav solar site http://sohowww.nascom.nasa.gov/data/realtime/ Vespine 01:56, 31 July 2007 (UTC)

Paraphilias

How many people have paraphilias? A.Z. 02:39, 29 July 2007 (UTC)

You guys don't know? I asked this on the article talk page as well, but no one replied. I don't want the exact number, just an approximation would be fine. A.Z. 18:37, 29 July 2007 (UTC)

One could argue that everyone probably has paraphilic tendencies somewhere deep in their psyche. They may be mild and we may never explore them, but they are there all the same. However, there is a more formal, clinical definition of paraphilia, and if you wish to use that as your basis, then, "It is estimated that there are 15 to 40 million Americans with paraphiliac tendencies in one fashion or another" according to Wikibooks [9]. Assuming this is correct and that Americans are no more kinky than anyone else, then we could estimate 5% to 14% of the population have paraphilias. Rockpocket 22:50, 29 July 2007 (UTC)

IS there something such milk allergy

some freind of mine asked me that question he told me that whenever he drinks milk, eat yougurt, cheese ... he feels sick and next think he does is throw out ?????? could anyone help me please in giving him an answer ?

Milk allergy. Your friend should also consult a doctor, as Wikipedia can give neither medical advice nor a medical diagnosis. As a bit of common sense, your friend should stop consuming anything that makes him sick immediately. Someguy1221 06:50, 29 July 2007 (UTC)

Yep. It might also be a psychological effect, vomiting upon eating certain foods due to some mental reason isn't totally unheard of. However, unless he's being forced to eat it (peer pressure or such), I doubt it's that. In the mean time, try having soy milk instead --L^ie! 07:18, 29 July 2007 (UTC)

It might actually be lactose intolerance. But yes, do tell him to see a doctor. Recurring dreams 12:05, 29 July 2007 (UTC)

Well, myself and some of my family have minor lactose intolerance (in large doses), but I've never heard of lactose intolerance causing vomiting. It tends to have... 'other ways' of showing itself -_L^ie! 12:14, 29 July 2007 (UTC)

computer INTELLIGINCE how far ?

Is it possible that a computer connected to 2 chambers ,can transfer objects in between by moving the particles one at the time if yes !!!! then what about humans or the DNA will cause a problem  ???

In theory, existing nanoassembly procedures could work like this, but very slowly and only to very very small things. Such procedures have never been developed for large things, in part because the process is quite time consuming. Even if ever possible on large objects, the problem with any living thing would be that living things are ever in a state of constant chemical activity. If you were to try and transfer a human one molecule at a time, during the process you would have two parts that could not function without eachother, and the human would die. The two obvious solutions would be to either do it very very fast, or freeze the human. The former would be extremely difficult, as it may generate too much heat (breaking and reforming the bonds of an entire organism in a fraction of a second takes a lot of energy), and essentially vaporize the person. The latter is the current science of cryonics, which has its own problems. Someguy1221 06:55, 29 July 2007 (UTC)

See also our article Transport layer, especially TCP and UDP for how computers move data from one place to another, and what sort of problems are involved --L^ie! 07:15, 29 July 2007 (UTC)

I completely agree with Someguy1221's summary - and would add that it's not enough simply to put the particles in the correct place - they would have to be moving in the correct direction and speed (notably to keep things the right temperature and to account for blood flow). Electrical flows in the brain would have to be correctly maintained. For objects that are made from solids (eg a block of wood), you might imagine we could do this - but for something made of liquids, gasses, colloids and other more dynamic materials such as living things - I think it would be very tough indeed. Your best approach would probably be to try to do it very rapidly - but the insane number of molecules involved in even a microscopic organism would make this all but impossible. The data rates required would be far, far higher than any frequency we are able to produce over any distance.

It is also possible that Heisenbergs Uncertainty Principle might cause problems here. For small particles, there are issues of being able to measure where they are and how fast they are moving that simply cannot be overcome because of fundamental physics limitations. If you don't know precisely where each particle is, you can't place it in the correct position in the reconstructed object. In Star Trek, the Enterprise's transporters (which are generally supposed to work in the way you describe) are equipped with 'Heisenberg compensators' (wouldn't you just know Wikipedia would have an article about this!) One of my favorite lines from the Star Trek authors: When asked "How do the Heisenberg compensators work?" by Time magazine on 28th November 1994, Michael Okuda, technical advisor on Star Trek, famously responded, "They work just fine, thank you."...and that's that!

SteveBaker 12:36, 29 July 2007 (UTC)

Speaking very conceptually, theoretically, and long distance here, like Leonardo in the 1400's describing things made practical in nthe 1900's, or like poeople in the 1700's describing electrical telegraphy made practical 100 years later, or like those in the 1860's describing airplanes made practical 50 years later, we presently have databases showing the human body sliced into very thin sections. In the one case, this has been done by CT scan, and in another case by literally freezing a human body and grinding away one thin layer at a time. At the present time, we have 3D printing, in which a device analogous to a computer printer lays down one layer at a time of a 3D object, using a variety of techniques, for rapid prototyping. We also have the ability to assemble atoms one at a time (in an early demo, they spelled out "IBM.") So in principle, in the future we should be able to analyze a small 3D object at one location, and fabricate a replica of it at another location. This capability in the foreseeable future does not extend down to the molecular or atomic level, but only captures the larger 3D details. To transport a small plant or animal would require molecular resolution, and vast bandwidth. We would not be turning the matter to energy at the sending end and energy to matter at the receiving end, but just sending assembly instructions. Certainly it would be at extremely low temperature: imagine trying to add atoms to a worm which was wiggling! I suppose the result would be a frozen creature at the receiving end which replicated a frozen creature at the sending end, starting with tiny objects like simple single cell organisms. Edison 13:42, 29 July 2007 (UTC)

Yes, it's possible to imagine how it might be done, and I'm not as pessimistic on this as SteveBaker. For example, you don't need to duplicate the thermal motion of every atom - you just need to put the particles in the right places and make sure that the temperature profile is about right. OK, you might have to jump-start the blood circulation to get the momentum going, but then you might not - after all, they can (usually) electrically restart hearts that stop beating. The same goes for electrical properties: you don't need to duplicate the position and trajectory of every electron, since all that matters are the relatively large-scale potential differences across membranes and synapses. (OK, so my arms are waving about wildly here.) I don't think that the Uncertainty Principle is going to be a show-stopper. You might disagree if you believe that consciousness is a spooky quantum thing, but I don't - I think it's an emergent property of matter.

Like Edison, I would start with bacteria and iron out the little niggles, like accidentally turning the organism inside-out, before moving on to multicellular organisms. --Heron 18:58, 29 July 2007 (UTC)

Let's get RepRap working first eh? SteveBaker 04:03, 30 July 2007 (UTC)

One thing that seems to be missing from the RepRap prototypes is a big red STOP button. That's the first thing I would have designed in. ;-) --Heron 20:26, 31 July 2007 (UTC)

Well, these are just lab prototypes - they move exceedingly slowly and are driven by fairly feeble stepper motors. You'd have to be amazingly careless to get hurt by one. They are comparable to an inkjet printer in terms of power - and much, much slower. In all likelyhood, a consumer grade machine would be fully enclosed with a power cut-off when you open the cover (like a dishwasher or a microwave). You'd want the machine to be enclosed so you could keep dust and such out of the molten plastic - and also to control airflow because the rate that the plastic cools is somewhat important. SteveBaker 02:37, 1 August 2007 (UTC)

"Shunning" in gulls?

Does anyone know the correct name for the behaviour wherein a sickly or injured gull will be driven from the larger gull flock by force and abandoned to fend for itself/die? From what I've read, albino gulls often get the same treatment? Shunning immediately came to mind but upon reading the article, that term seems to refer only to humans. --Kurt Shaped Box 08:20, 29 July 2007 (UTC)

May I ask why you've been asking about Gulls for so long now? Whoops, already asked. PitchBlack 08:44, 29 July 2007 (UTC)

Simple answer. I think that gulls are great. Why this question? Well, I saw an injured (broken wing) gull being 'shunned' yesterday. Every time it approaced the other gulls on the beach, they would attack it and chase it away (yet it kept trying to return). Its head was already covered in blood when I encountered it. Poor thing was only a fledgling too. I managed to catch it and take it to the local wildlife rehab man. Apparently, it's doing okay today. --Kurt Shaped Box 22:02, 29 July 2007 (UTC)

I still have Reference desk/Seagulls on my watchlist. Good times --L^ie! 11:54, 29 July 2007 (UTC)

So, does anyone have a serious answer to my question? Guys? --Kurt Shaped Box 16:10, 31 July 2007 (UTC)

what happens when photon struck proton ?

and when electron is strucked by photon ?

When a photon hits an electron that is part of an atom, the electron absorbs the proton energy and bounces up to a higher energy level. However, the electron cannot stay at this level for long, and when the electron falls back down, it releases that energy again as more photons, which produces light by a process called "photoluminescence"; fluorescent jackets emit light in this way. Laïka 17:37, 29 July 2007 (UTC)

sunrise to solar noon?

On a typical day in North America, how long roughly is the period of time:

• between sunrise and and solar noon?
• between solar noon and the beginning of civil twilight?
• the beginning of solar twilight and solar midnight?
• between solar midnight and sunrise?

--Sonjaaa 10:50, 29 July 2007 (UTC)

It depends on the time of year and your latitude. There is no 'typical'. Nights are longer and days shorter in the winter - so time between (say) sunrise and noon is shorter in the winter than in the summer. The further north you go, the more pronounced this effect is. Coming up with a 'typical' number means what? At an average latitude an average day of the year? SteveBaker 12:19, 29 July 2007 (UTC)

Exactly right. Case in point: think about in parts of Alaska when they have full days that are either light or dark.Mrdeath5493 16:56, 29 July 2007 (UTC)

Note that the period between sunrise and noon is rarely exactly the same as the period from noon to sunset. Astronaut 17:21, 29 July 2007 (UTC)

But the question was not about exact details. --Anon, July 29, 2007, 19:43:06.5 (UTC).

Yeh, but there are so many variables affecting daylight that the question is comparable to asking how big is an animal? HYENASTE 22:52, 29 July 2007 (UTC)

Yes, and there are pedants here who would reject even the question "What color is the sky?" with "Well, it depends" or "that depends on so many variables that it's impossible to say" (or, perhaps, "it depends on what the meaning of 'is' is").

If I knew the answers off the top of my head, or if I had time to do the research just now, I'd provide an answer for, say, 40° north latitude near the equinox, then explain how the answer varied towards the solstices, then explain how the answer varied at different latitudes. But I don't and I don't, so I can't just now. --Steve Summit (talk) 23:01, 29 July 2007 (UTC)

So you can't be bothered to work it out - yet you complain that nobody else will either? I think you'd have an exceedingly hard time convincing anyone that the particular latitude and time of year that you happened to choose was "typical" per the OP. The OP also went to a lot of care to list the precise meanings of terms like dawn and noon - which suggests that some measure of accuracy was forseen (if you are talking about the difference between midwinter in Alaska, midsummer in Alaska and any time of year in southern New Mexico - then the subtle distinctions between solar noon and 12:00pm are utterly negligable due to an error of something like +/- 6 hours due to picking the location. Note further that the error is of comparable size to the answer - which means that the answer is in every sense meaningless - which is why I (for one) chose not to try to find an exact answer. The best we can say is "between 0 and 12 hours" in answer to most of those questions. We are doing a better job by telling the questioner that they have made a poor assumption in asking the question he/she did than by misleading them with an utterly valueless answer. SteveBaker 04:01, 30 July 2007 (UTC)

Steve. Peace. I didn't say I couldn't be bothered, and I'm sorry if it sounded like I was complaining. —Steve Summit (talk) 04:13, 30 July 2007 (UTC)

Some useful data: US Naval Observatory —Tamfang 04:29, 30 July 2007 (UTC)

The original question is too general to really answer with precision but, I'd be interested in knowing:

• what is the precise moment which is called "sunrise"?
• what is "civil twilight"?
• what is "solar twilight"?

Is there a difference between the last two? JAXHERE | ^Talk 14:41, 30 July 2007 (UTC)

Twilight notes the specific definitions of Civil and Astronomical (what I presume is meant by "solar") Twilight. Sunset isn't quite as clear -- it notes that an optical illusion causes the sun to be visible even when entirely below the horizon, but I don't see a hard definition of sunset being defined geometrically versus optically. — Lomn 17:01, 30 July 2007 (UTC)

Disposal of medications

What is the proper way to dispose of medications that are controlled substances? The local hazardous materials disposal group won't accept them, and I'm worried that just flushing them may cause environmental damage. 69.123.113.89 14:39, 29 July 2007 (UTC)

Well, if you're just worried about environmental damage, sell them on the black market. Really, ask a doctor --L^ie! 14:44, 29 July 2007 (UTC)

At least in the UK (and surely other places too) any pharmacy will take them (not just the one that dispensed them). -- Finlay McWalter | Talk 15:29, 29 July 2007 (UTC)

First of all, how much are we talking about here? If you have a huge stash and have decided to change your ways, wash them down the tub and go have a beer. If you have extra that are out of date, or still in date and that you don't need, then contact your local DEA office here. They will probably tell you to just wash them down the sink. Don't sell them or give them away, as we all know this is illegal. Mrdeath5493 16:54, 29 July 2007 (UTC)

EDIT: I see now that most waste treatment plants in the states can't filter/treat organic waste like that found in medication. So, if you are from the U.S., contact the DEA for advice. I work in a pharmacy and we don't accept previously dispensed medications, not sure about others. If there is a Cardinal Health in your area, they're probably the only distributor of controlled substances and will likely have methods of disposing of them.Mrdeath5493 19:26, 29 July 2007 (UTC)

In Sweden, washing medications down the sink is considered highly polluting! We're urged to bring back our old medications to the pharmacy. As far as I know, they dispose of the medications by burning them. Lova Falk 18:44, 29 July 2007 (UTC)

Indeed New Zealand as well. It appears that this is sometimes practiced in the US too [10] although obviously not as common as it appears to be in most other developed countries Nil Einne 01:31, 30 July 2007 (UTC)

Uterine Fibroids

Uterine fibroids.... does it have any dangers longterm ?? shortterm?? — Preceding unsigned comment added by 212.107.116.244 (talk • contribs)

I've no idea, but your doctor is probably the best person to ask. Astronaut 17:16, 29 July 2007 (UTC)

Did you read our article on uterine fibroids?--Shantavira|^{feed me} 17:18, 29 July 2007 (UTC)

Zoloft pill life

How long can a bottle of zoloft pills last? I was thinking they could last for years. Would the chemicals and powders in the pills still work after they expired.--logger 17:14, 29 July 2007 (UTC)

If, as you suggest, the bottle has an expiry date, that would answer your question.--Shantavira|^{feed me} 17:24, 29 July 2007 (UTC)

You should consult a medical professional for this type of advice. Don't take expired medications without consulting with them first.Mrdeath5493 19:27, 29 July 2007 (UTC)

Because it's expensive to test drug's effectiveness as they age, most drugs are simply not tested for that and a blanket expiry date is put on all of them. It is therefore likely that it's completely unknown how long they last - or what adverse consequences might come from taking them after that time. There was a study done by the US army (I believe) who scrap millions and millions of dollars of drugs every year - and they found that most of the drugs they used would last well beyond the official expiry date. But there is no way for you to know whether this particular drug really does expire on that day or not - or what the consequences are of taking them after they've expired. So the safe advice is "Don't take them!". SteveBaker 03:48, 30 July 2007 (UTC)

Salt and health

The article on salt says: Overconsumption of salt can increase the risk of health problems, including high blood pressure. Anybody who knows what other health problems overconsumption of salt can lead to? Lova Falk 18:33, 29 July 2007 (UTC)

Theoretically, there is a lethal dose of salt. So you could technically eat enough straight salt in one sitting to kill you. The Salt Institute has a library of information on their website. Also they have one specifically addressing sodium and health. However, the tone of all the articles on the site seem to be more pro-salt than most medical publications. I personally believe that they represent a neutral standpoint and that most medical articles concerning salt apply to very few people.  :) Mrdeath5493 19:36, 29 July 2007 (UTC)

Ah, an institute of salt producers. Reminds me of when I was working in the food sector and we used to get press releases from the salt association. Do you know, they didn't think people eating too much salt was a problem? In fact, they tended to emphasise that athletes need enough salt to replace what they sweat out, even when the discussion was about the average person who got less than half an hour's exercise a day. I assume they were neutral, and the government-funded medical research was biased.... Skittle 23:04, 29 July 2007 (UTC)

I wasn't referring to any sort of actual scientific research, public or privately funded. When I said medical articles, I meant magazine or newspaper articles which tend to misinterpret the actual message (my fault as I was initially vague). A healthy person needs salt. Most people without a blood pressure problem can eat just about as much salt that might exist in whatever food they eat, and remain perfectly healthy. However, 20-30 year-olds read some mistaken magazine article and think they should be on a low sodium diet. The truth is that there is absolutely no proof that a young (<40) person that is healthy will see benefits from a low sodium diet...none. So, salt is bad if you have high blood pressure. Otherwise it helps you move, feel, and think (3 process that require sodium ions). Mrdeath5493 06:10, 1 August 2007 (UTC)

Walnuts - idle thought whilst snacking...

Why do walnut halves look like the human brain? --Kurt Shaped Box 19:46, 29 July 2007 (UTC)

Do they? I would have asked: why does the human brain look like a walnut half?- hydnjo talk 20:48, 29 July 2007 (UTC)

Its likely to do with trying to cram a large surface into a small volume, with a connection to a stem. The surface is folded, and comes out with bilateral symmetry do to the shape of the case or shell. GB 21:51, 29 July 2007 (UTC)

But why do the walnut and the brain need large surface? A.Z. 21:54, 29 July 2007 (UTC)

The cerebral cortex contains about two-thirds of the human brain's 100 billion neurons, organised in a thin layer of cortical columns. Higher brain functions (such as perceptual awareness, "thinking", language and consciousness) requires more neurons organised in this manner, but you are limited by the confines of the skull. In order for this large surface area to fit, the cortex folds in on itself, resulting in a series of ridges and grooves ((gyri and sulci) that give the brain its "wrinkled" appearance. I don't know why the walnut requires a large surface area. Rockpocket 22:32, 29 July 2007 (UTC)

As our walnut article points out, the modern walnut is the product of centuries of horticultural selection, so looking for a strictly "naturalist" evolutionary answer may be misleading. All that being said, I'm not sure why that particular nut would need that much surface area, though my guess would be it had something to do with water absorption/retention. --24.147.86.187 00:58, 30 July 2007 (UTC)

So they should amend that old -- ahem -- chestnut about apatosaurus brains being the size of a walnut to "apatosaurus brains are the size and shape of a walnut"! :) --TotoBaggins 18:28, 30 July 2007 (UTC)

A mouse brain...not like a walnut.

Actually - probably not. Many modern species of lower intelligence have much smoother brains because they simply don't need the density of cerebral cortex that humans, dogs, chimps, dolphins, etc need. It's possible that Apatosaur brains were both small and fairly smooth...like the mouse brain in the photo. I doubt that Apatosaur needed to be much smarter than a mouse. SteveBaker 23:48, 30 July 2007 (UTC)

Indeed. It is commonly said that the huge Stegosaurus had a brain the size of a walnut. --Taraborn 22:52, 31 July 2007 (UTC)

July 30

six-legged logging robot

I remember watching a show on the history channel (I believe) about the history of logging. When it got up to modern innovations, there was a six-legged robot which I believe was Swedish and roughly the size of a truck. It was designed with legs so as to be able to navigate over obstacles and difficult terrain, and to avoid doing damage to the forest floor--the legs would spread the weight out, and didn't scuff up the turf like wheels or treads do.

Unfortunately I can't manage to find any of this online. There's the occasional mention in robotics or mecha fandom forums, but all the links are dead. I have yet to even find a picture. Google searches turn up a million different things, like buggy chat-logging bots, but not giant forest logging robot bugs. Does anyone know more about this, or know where I can find more information? 172.145.184.137 00:19, 30 July 2007 (UTC)

I guess it's mentioned here: Talk:Mecha#Real-life_efforts (however, the address given there doesn't seem to work). It seems to be made by Finnish company "Plustech Oy" (or something like that). Such search in Google actually gives some links with pictures. There also seem to be some scientific articles mentioning it. --Martynas Patasius 01:00, 30 July 2007 (UTC)

Here's a rad video: [11] --TotoBaggins 13:39, 30 July 2007 (UTC)

cfl lamps

why cf lamps are said to lessen the electricity expense?

Why don't question askers bother to read articles like Fluorescent lamp before they ask? Nil Einne 02:07, 30 July 2007 (UTC)

Or the even more on point Compact fluorescent lamp article.

Atlant 11:58, 30 July 2007 (UTC)

Short answer: they are more efficient. They use less electric energy to produce the same amount of light. (Also, they last longer than conventional incandescent bulbs.) —Steve Summit (talk) 03:12, 30 July 2007 (UTC)

another short answer: they don't make as much heat. Gzuckier 17:38, 30 July 2007 (UTC)

A Question

I understand that I shouldn't be asking help for my homework, but I'm merely seeking guidance here and have conjured up a answer previously... So here it is, the question asks to describe the change of speed over time for 'the first 4 seconds of a sprinter's 100 m race', and here is the possible answer:

It started off at high speed (due t the first burst of speed from the launch pad, or whatever it is called) then the speed drops slightly (as the energy from the outburst is countered by resistance...) then the speed builds up until it reaches a point (I'm wonderin if this point should be higher/lower/equal to the first burst of speed) then levels off til the end.

Thanks!

That answer doesn't make sense. "as the energy from the outburst is countered by resistance"?!?! I certainly don't believe that the speed drops at any point in the first four seconds. Your words reveal a serious misunderstanding of simple Newtonian mechanics which is (probably) what the question is trying to test you on...and you don't know it...at all. Firstly - you need to clearly understand the difference between work, force and energy and between speed/velocity and accelleration and (perhaps) how drag works...although I'd be surprised if it were much of a factor here - the question probably even says "ignoring the effects of air resistance" somewhere. Since this is homework, I'm not going to tell you the answer. However, I'd like to point out that the reason you get homework is not to have you find the answer - but to learn how to get it. So start reading those six articles (or your physics text book which probably states it in simpler language) and maybe you'll learn something! Oh - and the 'launch pad' things are called 'blocks'.

Sorry for the trouble, I guess I wasn't thinking straight earlier on... well, I think the first bit of my previous 'answer' ought to be ignored, leaving the later bit where the speed builds up from 0m/s to a certain pt then levels til the end...right this time?

There would be an almost constant acceleration to near 10m/s in something like 0.1 secs, then for the rest of the 4 secs the runner would decelerate slightly when both feet are off the ground (air resistance), then re-accelerate when one of his legs are on the ground. I don't know the period of the average 100m runner's stride, it's probably a cycle of period 0.4s or thereabouts, so a periodic dip every 0.2s or so.

This is completely guess work and OR :) - maybe they accelerate over a few strides, but still i wouldnt imagine much acceleration over the last 3 seconds besides keeping up with air resistance Capuchin 09:47, 30 July 2007 (UTC)

I really don't believe air resistance is significant at 10mph. The formula for air resistance says that the drag force is proportional to the square of the speed - and the amount of power consumed to overcome that drag is proportional to the cube of the speed.

We know that at 120mph or so (terminal velocity for a skydiver with his arms and legs spread out to deliberately slow himself down) the drag force is equal to the weight of your body. At half that speed, (60mph) the drag is four times smaller. At 30mph it's 16 times smaller, at 15mph it's 64 times slower - so at a 10mph run (and for someone who has arms and legs not splayed out with a baggy paracuting suit) - the force due to drag is maybe 1/200th of the weight of our skydiver...tiny...having lighter shoes will have a bigger effect! SteveBaker 23:38, 30 July 2007 (UTC)

Not true! For sprints, air resistance is absolutely critical. The acceleration of a sprinter is much less than 1 g. A world class 100 m averages closer to 20 mph (actually a bit faster than that). To cover 100 m in 10 s, the acceleration is 2 m/s², that is, 0.2 g. If the air resistance at 20 mph is 1/50 of the runner's body weight, that's a 10% effect in how fast they can accelerate! Even a 1% difference would be quite significant for races. OK, I see now that you may have meant the runner doesn't slow down appreciably over the course of a single stride. That is certainly true. --Reuben 01:27, 31 July 2007 (UTC)

Exactly - sure there is some air resistance - but it's the same for everyone - so the fact that a 1% difference in accelleration can win or lose the race isn't the point here. The question is whether it has the ability to slow you down between paces to any measurable degree...I really doubt that. I guess one significant question is whether the sprinter endeavors to keep one foot pushing against the track at all times - or whether he/she spends appreciable time in free-fall with neither foot providing traction as (say) a hurdler would? Logically - to get the most from your muscles, you'd want to always be pushing against the track because 'air time' is wasted. But I guess that's simply geometrically impossible under the circumstances - if one foot was always on the ground at all times, that would be a walking race - not running. But as far as the OP is concerned, he has far bigger concerns with getting this homework done. Just ignore air resistance! SteveBaker 01:55, 31 July 2007 (UTC)

Computer games causing migraines

Hope this in the right place - it seemed to vaguely fit under 'biology', heh.

3D games like first person shooters and platform games give me massive migraines and make me feel sick - curious as to whether there is an article about this on Wikipedia? I'd search for it myself, but I'm not really sure what to look for :) Thanks in advance! Kamryn · Talk 10:02, 30 July 2007 (UTC)

Oh never mind - found what I was looking for in motion sickness :) Kamryn · Talk 10:07, 30 July 2007 (UTC)

There are other possible reasons why you could have a headache or feel sick after playing games. Are you playing on a TV or Computer Monitor? If you are on a CRT monitor, make sure you have the refresh rate turned up higher. Two other things that work for me (Personal Research, don't take it as fact, but motion sickness is depedant on the person yes? :D) is "zooming-out" in those types of games, I.E. play in third person mode if possible instead of looking through the "eyes" of the character. Also, incredibly smooth animation/frame rates gives me a headache, perhaps due to the fluidity of the motion, so I tend to turn the graphics options a little higher to maintain at around 30FPS (which spikes downards and causes jerkiness so often) instead of higher frame rates. --GTPoompt(talk) 12:55, 30 July 2007 (UTC)

My little sister has never been able to play 3D video games (well, if it's locked in a 2D perspective with "depth" that's one thing but you know what I mean) because she's unable to visualize the full 3D environment around her from the image data available at any one time on a 2D screen. This isn't a matter of fogetting what was behind you the instant you turn around, but rather not being able to construct a 3D visualization (or usually more importantly just a 2D overhead view) from just the player's perspective. And games with dynamic third-person cameras are even worse for her since it's an extra level of disorientation when the camera moves relative to the character. Also she's disoriented by the 3D projection onto the screen- I guess she overrelys on parallax effects and such to assist in depth perception. Any one of these things could be your problem --froth^t 15:14, 30 July 2007 (UTC)

How old is your sister? That really surprised me: "she's unable to visualize the full 3D environment around her from the image data available at any one time on a 2D screen", unless, maybe, she's very young. --Taraborn 22:38, 30 July 2007 (UTC)

This sounds strange since ultimately the image is rendered on to the 2-D retina on the back of the eyeball. It's rather easy to fool. In fact, can she watch movies which is basically the same principle. --Tbeatty 06:21, 31 July 2007 (UTC)

She's 14! As for movies, you don't exactly need to do anything to watch a movie, while in a game you need to have a pretty firm grasp of your environment for tasks such as path finding and defending yourself from enemies... in games like counter-strike (especially on smaller maps like gg, fy, aim, etc) you need to know right where your team is covering and where you're sure no enemy could be if you don't want to get shot in the side or the back --froth^t 16:17, 31 July 2007 (UTC)

I'm also pretty sensitive to some kinds of game (and other 3D graphic display)...and I'm a professional game programmer! Several things I've observed:

1. I'm more affected when someone else is in control than when I'm playing...yet I can watch 3D animated movies on TV or in a movie theatre without any problems???
2. The larger the screen - the worse it is. Try using a smaller screen.
3. The greater the disparity between the field of view of the camera in the game and my own eyes, the worse it is. Most games use a wider field of view than our real eyes - and we sit so far back from the screen (typically) that the screen subtends maybe 20 degrees of your view - where the game is drawing maybe 60 to 90 degrees. This is odd because it's in direct contravention of (2)...but there it is.
4. Poor framerates make it much worse. A game that runs at 60Hz is much less troubling than one that runs at 20Hz.
5. In games where the eyepoint skids sideways as you turn your avatar around - they'll make my stomach turn sour in less than a minute - guaranteed!
6. 1st person games are much worse than 3rd person...except for driving games where the reverse is the case. (Go figure?!)
7. 2D games and 3D 'god' games like Civ or SimCity where there is no perspective, never bother me.
8. Some specific games are bad - for no reason I can explain. All of the James Bond games on Nintendo machines make me want to puke...no matter whether I play in 1st person or 3rd person or even in parts of the game where you're driving a car or something. Dunno why.

As for your sister...it's rare these days but: Babies are commonly somewhat cross-eyed at birth and usually learn to focus and get their eyes lined up within just a few days. In a few rare cases where this doesn't happen and the baby stays cross-eyed for weeks or months, the part of the brain that is responsible for 3D 'understanding' never develops. Of people born in the 1970's or earlier, this is amazingly common - maybe 10% of people have the problem. These people are often unaware of their condition until they try to use 3D glasses or those stereogram things...which do nothing for them. More recently, doctors test babies for this problem and work to fix it before it's a permenant problem - so it's much rarer these days. I did see somewhere an article on the 'net by a lady who managed to teach herself to see in real 3D at age 30 or 40 years - so it's possible that it can still be fixed. SteveBaker 23:22, 30 July 2007 (UTC)

I'm also one of the people for whom some video games trigger migraines. I first discovered it with DOOM, and since then I've noticed that pretty much any first-person shooter does the same thing. A few other games do it -- I think the frame rate does have something to do with it. Pity, too; it's usually the games I'm most interested in that do it. (Messes me up for a whole day; requires crawling under the pillow in a dark room.) --jpgordon^∇∆∇∆ 22:18, 31 July 2007 (UTC)

There was actually a really interesting article by Oliver Saks in the New Yorker a few months ago about binocular vision and the amazing fact that some people who do not have it (being born cross-eyed or otherwise unable to physically form a coherent binocular image) were able to reasonably develop it at a much later age in life after a lot of terribly difficult training. I forget the details but it was pretty interesting, and Saks suggested that this probably meant that the "you need to develop it when young or it is impossible" paradigm (which has been around for a loonggg time) is probably not the whole story. --24.147.86.187 23:57, 30 July 2007 (UTC)

Just an FYI: it's Oliver Sacks. 38.112.225.84 06:10, 31 July 2007 (UTC)

Right - that's true. As I explained, there was a lady on NPR who managed to train herself to see in 3D for the first time at age maybe 30/40 years (it must have been a stunning revelation!) - and gradually, over the course of many months gained full 3D vision. So yeah - it's possible to get it back. But I still think it's true to say that if you didn't just happen to get it right soon after birth then it's not going to come back "naturally" when the vision problem is corrected - it takes active training...and the suggestion was that it's neither easy nor certain. See [12] for example. (Oh great...they called the patient "Stereo Sue"...sheesh!) SteveBaker 01:40, 31 July 2007 (UTC)

alkyl group

Why is the alkyl group electron releasing? In the wikipedia, it just said in reference to hydrogen, alkyl groups are electron releasing constituents, is there a reason to explain this besides it is just because of inductive effect?

As there are no multiple bond mesomeric structures or lone pairs the inductive effect is the only cause for this behavior.--Stone 15:20, 30 July 2007 (UTC)

Could also do hyperconjugation from the H on the first C of the alkyl chain. DMacks 17:57, 30 July 2007 (UTC)

Right!--Stone 07:32, 31 July 2007 (UTC)

Radio powered

If crystal radioes can create sound by remodulating the powerful-enough radio waves, is it possible to instead harness the power of the radio waves to power something? Like self-recharging batteries or something? And would this be anywhere near anything that could be considered efficient? (not that blasting hundreds of square miles with radio waves and letting the escaping ones go to waste is efficient in the first place..) --froth^t 15:01, 30 July 2007 (UTC)

Yes it can be done. No it is not efficient. I think they have used sound powered electronics once when the electronics didn't need much power and couldn't be hooked up to the power lines. It was a lot easier than replacing the batteries on all of those devices periodically. I can't remember the exact circumstances. Radio powered also wouldn't work in Faraday cages, although you probably wouldn't spend much time in them. You might be able to have a radio output in your house to power wireless devices in a not too inefficient way, but I don't know if this is what you want. — Daniel 15:26, 30 July 2007 (UTC)

See also wireless energy transfer. --TotoBaggins 15:46, 30 July 2007 (UTC)

Radio-frequency identification RFID chip is also powerd by the radiofrequency absorbed by the antenna.--Stone 16:07, 30 July 2007 (UTC)

The principal problem you face is the inverse-square law; as you get farther and farther from a typical omnidrectional (+/-) radio broadcasting antenna, you need an enormously large receiving antenna to intercept even a small fraction of the original broadcasting power. That 50,000 watts that WABC is pumping out in the New Jersey Meadowlands has become just a few microwatts when it reaches your crystal radio; that's why the volume of sound produced by the earpiece is so low.

On the other hand, microwave power transmission uses a focused beam of microwaves to move power from one point to another. Over the distances that are envisioned, it's pretty easy to build antennas big enough to beat the beam dispersion caused by the inverse square law.

Atlant 16:40, 30 July 2007 (UTC)

Sure. I remember an article in Popular Electronics in the early 60s or so, which was a transistor radio powered by tuning a second tuner to any powerful station around. Gzuckier 17:40, 30 July 2007 (UTC)

Global Warming?

Is it true that global warming is caused by Merecats?--172.144.134.131 16:04, 30 July 2007 (UTC)

Absolutely, You've penetrated their plan to turn the whole world into appropriate territory for them to live in. Now you have to go into hiding. Gzuckier 17:41, 30 July 2007 (UTC)

Do you mean to ask whether global warming is caused by mere cats, or by meerkats? If there were enough of them suspended in the atmosphere, I think they would both cause cooling rather than warming. --Reuben 17:52, 30 July 2007 (UTC)

Yup. Meerkat Manor will soon be retitled Meerkat World and air 24 hours a day. Clarityfiend 20:07, 30 July 2007 (UTC)

Um, to answer the question a little more explicitly: No, not unless one could make an argument that they contribute to a significant portion of the CO2 in the air.Mrdeath5493 02:56, 31 July 2007 (UTC)

Plant defense

Plant_defense_against_herbivory states three different chemical groupse of compounds used for protection against herbivores: nitrogen compounds (including alkaloids, cyanogenic glycosides and glucosinolates), terpenoids, and phenolics. The groupe of altered fatty acides is not mentioned. But substances like Cicutoxin or Falcarinol are also used against herbivores and they derive from the condensation of acetyl CoA and subsequent dehydrogenation to form the double and tripple bonds. Should this group be included?--Stone

You seem to know a lot about it - and it sounds like you are probably right - it should be added. However, please remember the importance of referencing your sources - that is what makes your addition totally non-controversial. SteveBaker 23:04, 30 July 2007 (UTC)

You are right, referencing the facts is important. I will add the group of chemicals to the article!--Stone 07:32, 31 July 2007 (UTC)

I think there are some plants that have enzymes that destroy vitamin B. Any animal that dines exclusively on that kind of plant will get a vitamin deficiency and die. GB 10:55, 1 August 2007 (UTC)

Animal reproduction

One thing I find fascinating about sharks is that they are able to give birth three different ways, and are even known to reproduce asexually. What other groups of animals have such reproductive diversity? Enok^talk 21:44, 30 July 2007 (UTC)

I seem to recall it being a plot point in the original Jurassic Park novel that certain frogs had the ability to change sexes. See Hermaphrodite for more on that front. --Mdwyer 01:56, 31 July 2007 (UTC)

Paper

How much paper is produced from an average sized tree? (In printer paper sheets, preferably). I would like to cite this for a letter to the editor at the Windsor Star. Thank you. Crisco 1492 23:48, 30 July 2007 (UTC)

According to http://www.bc.com/ (a paper company) a cord of wood (128 cubic feet) produces "nearly 90,000 sheets of bond-quality paper or 2,700 copies of a 35-page newspaper". [13] comes up with 80,000 sheets...so that's probably about right. How many cords do you get out of one tree? Well, it varies wildly between age and species of course...the US forestry service defines a tree suitable for cutting down as: A live tree of commercial species at least 9.0 inches d.b.h. for softwoods or 11.0 inches for hardwoods, containing at least one 12-foot sawlog or two noncontiguous 8-foot sawlogs, and meeting regional specifications for freedom from defect....so let's go with 10" diameter and 16' length. That's 35 cubic feet. But paper pulp can use more of the branches and skinnier stuff - so it's probably a lot more than that for paper as opposed to solid planks and stuff. I'm going to guess 50 cu.ft per tree. So 2.56 trees is a cord - and a cord is 90,000 sheets of typing paper or 2,700 copies of the Windsor Star. I think they're getting about a thousand newspapers per tree. The Windsor Star website says that they use 25% to 30% recycled content - so you should probably assume 1500 copies per tree to be on the safe side. I think you'd be on shakey ground if (as I suspect you are about to) you start telling the newspaper that it's causing massive deforestation because it printed something you didn't like! SteveBaker 01:22, 31 July 2007 (UTC)

Nah, if it were something about what I didn't like, it would be how I go through all my red pens proof editing their articles :P (not seriously, i only go through one a month). Actually, it is resume related. So thus, if 90,000 sheets of paper are taken from one cord, and a cord is approximately 2.56 trees, then the amount of printer paper would be around 35,150 sheets.

Thanks Steve. Crisco 1492 14:38, 31 July 2007 (UTC)

Ah! Sorry for jumping to the wrong conclusion. Anyway - that number has a massive error bar on it - but at least you know where the numbers came from and how it was worked out. That oughta be enough for a job application...unless of course you are applying as a fact-checker...in which case maybe you should check my facts first! Good luck with the job hunting. SteveBaker 20:06, 31 July 2007 (UTC)

July 31

Turning the Pampas into forest

As the wikipedia article on the Pampas suggests, the only reason that the more humid part of the Pampas doesn't have a deciduous forest like its counterparts in the north temperate regions have is because of edaphologic reasons, e.g. the ground being too compact to allow tree growth. My question is, if people were to plant extensive parts of the Pampas with trees, would the soil eventually break up enough to allow trees to grow naturally, so that native species of trees that are only present along riversides to colonize areas away from rivers?

Thermo Wells

How do temperature gauges mounted in thermo wells work? Also, i would like to know about the construction of thermo wells.

Looks like we need an article on thermal blanket - which is the general term. A thermal well is a "deep" thermal blanket based on the same technology. -- Kainaw^(what?) 12:45, 31 July 2007 (UTC)

OK - created the article. As for the temperature gauge, it appears to just be a regular thermostat. If the soil is too cold, it increases the heat. If it is too hot, it decreases the heat. -- Kainaw^(what?) 12:55, 31 July 2007 (UTC)

How MUCH air moves with the wind?

Short: I'm working on a simplified weather simulator, and having trouble finding information about how much -- what volume, mass or molar quantity -- of air moves with the wind caused by pressure differential.

Detail: I'm making several gross simplifications in my sim, and using a lot of descrete time, quantity, etc., units where the real answer is more differential than that. So I've got, let's say, a column of air in my atmosphere. To simplify, let's say this column is isolated -- we won't worry about the columns surrounding it, and just talk about up & down in THIS column. At some point in the column, I have a cubic meter (let's say) of air that is 772 mmHg. The "next" M^3 of air up in my column is (let's say), 762 mmHg. I want to "mix" these two bodies and, using PV=nrT, I know that -- once everything settles out -- the two air-masses will try to move toward their "average" of 767 (assuming no other forces, like the remainder of the column.) There is also mixing of temps, proportionate to how much each air "bucket" contributed, etc.

So far, so good. I've got this much "down."

What I DON'T know is: let's say that, rather than a M^3, my "buckets" are 10kM^3 -- so now it's easy for me to see (imagine?) that this exchange/transfer/equalization takes some amount of time. There's not just an instantaneous "poof" and it's over. And that, btw, is "wind" (although, in this case, the "wind" I'm describing is vertical, and more likely called "convection.")

So my question is: once I've figured out how the two adjacent "buckets" of air are going to try to equalize (the "easy" part), how do I figure out how long it will take for that exchange to take place (the question part)?

Is there some sort of "amount of air that will flow past an area size A in an amount of time T, given a pressure differetial ΔP" formula?

Thanks! Oliepedia 15:09, 31 July 2007 (UTC)

To solve this I'd recommend considering the mean speed of the gas particles across the pressure boundary - looking at ideal gas or gas laws might lead you to find an expression for this but I think it's something like sqrt(RT/?m) times a constant - you can consider the number of gas particles going in one direction and the number going in the other direction to give the change in pressure etc after a small period of time.

Right. That's basically my question: what is this formula? I haven't been able to find it under and of the gas-law sites, ideal or otherwise. (For my purposes, I'll be using ideal, and ignoring the fact that things aren't ideal in my sim.) Oliepedia 00:10, 1 August 2007 (UTC)

You can find it here Root_mean_square#Root_mean_square_velocity

You'll probably need the component of that in one direction, I think that's 1/sqrt(3)

Next you need to be able to convert an expression for "amount of air that will flow past an area size A in an amount of time T, given a pressure differetial ΔP" into a differential equation and hopefully solve that. (not necessarily easy or do-able)

That's one of the short-cut simplifications I plan to make in the sim, too -- that I'll be doing this with descrete time (i.e., 1 minute's worth at a time), vice doing actual differentials. Oliepedia 00:10, 1 August 2007 (UTC)

to summarise find (or ask about) an equation that gives the velocity of gas molecules across an area in terms of p,T,gas type. Then find the change on either side of the boundary to get the new conditions (you'll need to take into account the average energy of the molecules on one side and the molecules that have moved in), next solve this eqaution (it's a differential equation - maths desk might help more).

Did that supply the missing info?83.100.252.241 17:37, 31 July 2007 (UTC)

Sort of. The thing I'm missing is the "how much air moves in a given time period?" part. Oliepedia 00:10, 1 August 2007 (UTC)

As for your question about the computer sim - I'd recommend (once you've got a solution for AxAxA buckets) splitting up your 10000Ax10000Ax10000A buckets into buckets of size A, and finding the change in each small bucket in time t. Then run the simulation and observe what happens.?83.100.252.241 17:45, 31 July 2007 (UTC)

Right. THAT part I understand. I just can't seem to find the "how much air should I be moving around for a given time period?" formula, and I'm not sure where to look.

Thanks! Oliepedia 00:10, 1 August 2007 (UTC)

Perhaps a better restatement of the question

An example: Let's say I have a box, volume V, pressure P. I have another box, volume V', pressure P'. I put them together and open a hole between them area A. The ideal gas law tells me how to figure out how the two boxes will eventually reach equillibrium. My question is: What is the formula for figuring out how the pressures changes over time? Or, if no one knows that, what is the forumula called? Or what sorts of terms do I want to put into Google? I'm not even sure what to call what I'm looking for, here.

Thanks! Oliepedia 05:14, 1 August 2007 (UTC)

leather

1. Is it true to say that leather is made from the Stratum corneum or are other parts of the skin included?83.100.252.241 15:25, 31 July 2007 (UTC)

2. If so what are the forces between the dead cells that give leather/skin its strength?83.100.252.241 15:13, 31 July 2007 (UTC)

3. Can anyone supply a link that shows a microscopic picture of leather (or a diagram) showing its similarity (or remnant structures) in comparison to the skin it is made of.83.100.252.241 15:25, 31 July 2007 (UTC)

oral chelation

I need information on oral chelation both positive and negative side effects and possilbe organ toxicity especially related to kidneys.

See our article on chelation therapy for some information. Note that oral chelation therapy has not been found effective in clinical trials. TenOfAllTrades(talk) 16:52, 31 July 2007 (UTC)

Size of Euro Banknotes

What ios the logic behind the selection of the size of euro banknotes. —The preceding unsigned comment was added by 202.70.64.15 (talk • contribs) 17:45, July 31, 2007 (UTC)

Euro banknotes - larger notes are worth more? was there something more specific you were thinking of?83.100.252.241 17:48, 31 July 2007 (UTC)

Different sizes also make it easier for people with impaired vision to distinguish notes. Flyguy649 ^talk _contribs 17:52, 31 July 2007 (UTC)

Also, very large or very small notes would be rather inconvenient, both for people and for machines (such as ATMs and cash registers) that need to process them. Combine this with the desire to maximize the size difference between different notes (to make them easier to tell apart) and you'll probably get something fairly similar to the sizes actually selected. —Ilmari Karonen (talk) 22:37, 31 July 2007 (UTC)

Well, in the US, where all the money is the same colour, that would make sense, but euros are coloured differently. DirkvdM 05:59, 1 August 2007 (UTC)

Most countries banknotes are coloured differently but are different sizes. Both features help people (and machines) differentiate different denomination banknotes from each other. Also, as you pointed out, it's far easier to see the different denomination notes when they are stacked in a wallet, pile, cash register, etc Nil Einne 13:01, 1 August 2007 (UTC)

One advantage is that it's easy to pick a certain size out of a wallet. I've got 5, 10, 20 and 50 euro notes in my wallet, ordered by size and the higher nominations are easily distinguishable from the lower ones when I open the wallet. No need to fumble about. DirkvdM 05:59, 1 August 2007 (UTC)

If you see not properly or you are colour blind size would be a good help for you.--Stone 11:41, 1 August 2007 (UTC)

What happens if you are dimensionally challenged? --JAXHERE | ^Talk 15:10, 1 August 2007 (UTC)

What is the difference between light and EM energies besides frequency?

others have dodged this question rather then replying it. To say that light is quantized (photons) and EM is not does not answer the question.

That isn't an answer because it is not true. See electromagnetic spectrum. The difference is frequency/energy. Notice (when you read the article) that frequency and energy are related based on Planck's constant. -- Kainaw^(what?) 18:08, 31 July 2007 (UTC)

(EC) There is no difference; visible light is a kind of electromagnetic radiation (that is, it is EM radiation with a particular frequency). It's like asking "what is the difference between an apple and a piece of fruit?". --TotoBaggins 18:12, 31 July 2007 (UTC)

That's right - light is EM radiation of a certain frequency. Other measures are used (wavelength and energy) but these three things are directly related (energy is proportional to frequency and wavelength is inversely proportional to them). In other words all light and EM radiation can be described by a single variable - the frequency (intensity is the amount of it).

Thats the current level of understanding (ive not included polarisation).

Different frequencies of EM radiation interact with matter in different ways. The energy of light wave matches the difference in energy between outer electron orbitals, so that it can be absorbed or emmited by this mechanism. X-Rays have similar energy to the inner electrons in atoms, and so can knock out those electrons. Gamma rays have energy in the realm of nuclear transitions, can so can get a nulceus into an excited state if it is the right frequency. GB 11:03, 1 August 2007 (UTC)

From Light: "Light is electromagnetic radiation with a wavelength that is visible to the eye." The 'eye" here is unspecified, so what is light to a bee is invisible ultraviolet electromagnetic radiation to a human. What is invisible infrared to a human may be used by a Pit viper to track its prey. The part of the EM spectrum which is "Light" for humans is about one octave, if you picture a long keyboard with keys stretching to a practically unlimited distance to the low frequency and high frequency directions. This tiny band of wavelengths makes the task of focussing and creating a sharp image easier for the eye than if longer and shorter wavelengths had to be formed into an image. Distinguising these hues or seeing these colors may have some special survival value compared to a higher or lower frequency band. See also Visible spectrum. Edison 17:41, 1 August 2007 (UTC)

Vitamin Scare

I wanted to start to eat healthy and make sure that I was getting all the vitamins I need on a daily basis. I decided I will buy some mutlivitamins and take them during dinner everyday. However, an alternative medicine expert (well, I don't know if she is really an expert) informed me that some of the vitamins in the multivitamins are not absorbed in my body because either they need to be in another form (liquid), or they need to be taken seperately or they are counteracted by another vitmain. Also, she informed me that, in fact, some of the vitmins are too dangerous for me to take. Does anyone have any facts on this? Would it be beneficial to even bother taking these mutlivitamins? --WonderFran 19:40, 31 July 2007 (UTC)

See our Vitamin supplement article for general information, but do not treat it as medical advice. If you want medical advice, see your doctor. --Heron 20:33, 31 July 2007 (UTC)

Experts in alternative medicine are generally, by definition, not experts in actual medicine. 151.152.101.44 21:13, 31 July 2007 (UTC)

I do know that a lot of calcium pills are made from sea shells, and people claim those aren't easily absorbed by the body compared to other sources. But then again, the competitors of the sea shell variety claims most of that, so I'm not sure if that's even to be trusted. --Wirbelwindヴィルヴェルヴィント (talk) 21:14, 31 July 2007 (UTC)

I have made some comments and given some links on the discussion page of the Vitamin supplement article. I think you should not take multivitamins but instead eat a varied and healthy diet. 80.2.221.47 20:20, 1 August 2007 (UTC)

TECH CHALLENGE - The missing Ni-MH battery- Can you find one ? In america? of power to run a car?

Information has it that some oil companies have bought control of the company that owns the patent on the Ni-MH battery of the type that was used to power the GM EV1 and the Rav4Ev types; and are not allowing anyone to make the higher power ni-mh's (they are only allowing the smaller types that you would use in your phone, etc. The story goes that Detroit and the Oil companies are delaying the electric car (full size) because they don't want to lose the money in oil and for detroit, parts sales for ICE types. FYI: Some RAV-4 EV's that were "saved" from the recall actually still are using the same Ni-MH "green" batteries as were original equipment and get up to 100 miles on one charge that costs about 30 cents. (GM actually had some people put in jail they say for not letting them crush their recalled cars the ev1) To test the assertion we tried to buy a 12 volt Ni-MH battery in the USA. So far after a week, no luck. Big runaround? Everyplace says they will get back with us but either say they can't or give us phone numbers that don't work, or don't answer. Is it true? Can anyone find a 12 volt Ni-MH battery of the power (ie 75-125 amphours) for sale? Thanks! If you can you are truly blessed. Give me the link or phone to this place. Please don't put up battery finder websites.. they never have what we need (12v @ ~100amphours). An actual link to an actual seller of that actual product is what is needed. 209.16.117.50 20:15, 31 July 2007 (UTC)209.16.117.50 20:22, 31 July 2007 (UTC)

Tape 40 - Makita 3 amp-hour batteries together. If nobody has built the car, why would someone have built the battery? So I think your theory is urban legend, if that. There doesn't need to be a conspiracy to sell oil. pLenty of people want/need it. --Tbeatty

I'm not saying there is any conspiracy (I think it's silly, a variety of people may have their own reasons for something and may work to it, but it doesn't mean they all meet up and agree to some vast conspiracy). However to presume that just because there is a high demand for oil (which there is) means that there is no reason why those who would profit from oil won't want to try and stop developments which may lesson the demands for oil is a plain silly. If the electric car was a success (which is a big if) then it's likely it would have reduced the demand for petrol for cars and also the overall energy consumption by cars. Cars are clearly a not unsubstanial contributor to the demand for oil. It's resonable to assume then that if electric cars were successful enough, there would be a noticable drop in the demand for oil. And it's resonable to assume that the companies who make money from said oil won't want this to happen. This doesn't mean they actually did anything, but it does mean that it's a bit silly to say that because there is a large demand for oil from other sources, no one is going to care about the demand from cars Nil Einne 15:12, 1 August 2007 (UTC)

It's a false premise on the mistaken belief that these is a monopoly. Car companies would not halt the development of new technology because it competes with old technology. Only in a monopoly would this happen. Take the Prius. It is a huge competitive advantage to Toyota and they developed it to exploit the new market and gain market share over their competitors. Lacking in marketing foresight is not the same as inhibiting development. IF GM could build and sell a car for a profit that ran on cow dung, they would do it. The problem is that market analysis says they will not get the volume of scale necessary to support the development. Once that changes, a car maker will make the cars. GM doesn't make money by keeping the price of oil high, they make money by beating other auto manufacturers and that requires making correct investment decisions for future cars. If electric cars are viable, someone will make them and sell them (just like Toyota Prius). Sometimes prodcuts come before they are ready and they are not viable so they are cancelled (GM EV1, Apple Newton, etc). This is basic free market economics. Oil companies also compete and the are all looking for new markets. I'm just guessing, but Hydrogen cracked from petroleum will probably be the cheapest source for hydrogen batteries so batteries are potentially a huge market for oil compaines. The Green hydrogen from water will probably be the most expensive. --Tbeatty 16:08, 1 August 2007 (UTC)

Incidentally, "auto quality" is a historical analysis that you can use to test this theory. 20 years ago, a similar argument was made that GM/Ford/Chrysler built crappy cars on purpose because they wanted the consumer to have to buy a new car ever 2-3 years. When Japanese cars started to sell quality, it became apparent that this was not a viable strategy (if it ever was). The reason that quality was not higher was becasue consumers were indifferent to the quality differences on the car market until Honda/Toyota started selling very reliable cars and htis became a significant market segment. There are still quality differences between models but it's market segmentation that drove quality in both the current and previous generation. Competition improved the product even though on it's face it would seem each company would have lower costs if they sold crappy products. Cost is only one side of the equation and revenue is the other. Car makers will build cars if revenue-cost=significant profit over the risk free rate of return of the investment. It could be widgets, or electric cars or SUVs. --Tbeatty 16:17, 1 August 2007 (UTC)

See also Electric car#Controversy and watch Who Killed the Electric Car?. DMacks 01:12, 1 August 2007 (UTC)

Does petroleum ether (or ligroin) evaporate fully?

I have a jar with a mixture of some lipids and either petroleum ether or ligroin (It's called "lacknafta" in swedish and I think it translates to ligroin) and I want to separate these two. If I leave the jar without a lid in a ventilated place, will all the petroleum ether or ligroin evaporate fully or will something be left behind?

Braner 20:40, 31 July 2007 (UTC)

Analytical grade petroleum ether should eventually evaporate completely. If there is a lot of lipid dissolved in it, the last bits of the ether may take kind of a long time to evaporate. To some extent, a careful sniff will tell you when the evaporation is complete. ike9898 20:53, 31 July 2007 (UTC)

Given that "Generally laboratory grade ligroin boils at 60 to 90 °" from Petroleum ether the evaporation could take a long time - why not use a hot water bath to encourage it.. (remember NO NAKED FLAMES, sparks, etc) please don't intoxicate/set fire to yourself..87.102.7.85 21:06, 31 July 2007 (UTC)

Curiously swedish wiki seems to think 'lacknafta' is turps substitute? Or at least links to those pages - I'm guessing you can smell the difference between the two (petrol and turps) - possible a mistranslation of the words 'mineral spirits' which could mean either. If it is turps substitute it's going to be much more difficult to evaporate.87.102.7.85 21:16, 31 July 2007 (UTC)

http://translate.google.com/translate?hl=en&sl=de&u=http://www.woxikon.de/swe/lacknafta.php&sa=X&oi=translate&resnum=9&ct=result&prev=/search%3Fq%3Dlacknafta%26hl%3Den%26safe%3Doff%26sa%3DN maybe it is a dual use word?

According to the swedish national encyclopedia "lacknafta" translates to "white spirit" and some synonyms include crystal oil (kristallolja), ligroin and mineral turpentine (mineralterpentin). It contains aliphatic and aromatic hydrocarbons and it can be bought at many places, including gas stations. I don't know if anyone can help me more with this information, but thanks to those who have contributed so far.Braner 22:47, 31 July 2007 (UTC)

not sure at the moment what 'crystal oil' is but unforntunately the mineral turpentine will not evaporate well at room temperature, so the answer to the original question is no.

(I think the 'crystal oil' may mean 'mineral oil' (mineral=crystal?)

But if I place the container in hot water under a fan? Won't that make everything evaporate?Braner 17:04, 1 August 2007 (UTC)

I'm not optimistic - the white spirit has a boiling point well over 100C, plus it being mixed with lipids may slow the evaporation, the fan would help - since the bp is higher than the bp of water spreading the mixture out on a thin plate to increase surface area may help. Your best bet would be distillation apparatus - a still.83.100.138.237 17:20, 1 August 2007 (UTC)

commercial uses of amino acids

I'd like to know commercial uses for amino acids other than human/animal nutrition. Are certain amino acids used a precursors for making other chemicals/drugs? Any other type of use you can think of? Thanks!! ike9898 20:50, 31 July 2007 (UTC)

Sure, see Cysteine#Applications and CBS catalyst, a proline derivative. Rockpocket 21:06, 31 July 2007 (UTC)

MSG

Polyaspartic acid can be used in water treatment and as a highly absorbent hydrogel. DMacks 02:49, 1 August 2007 (UTC)

Aspartame --antilived^{T | C | G} 05:45, 1 August 2007 (UTC)

Aircraft speed through moving air (Title updated for clarity)

I remember back in grade school, we had math problems where an aircraft is moving at a certain speed in a certain direction, I'll just say 500 mph going N. And the wind speed is 100 mph going N, so the resulting speed of the airplane is 600 mph. I learned stuff like this even in college physics. Certainlly, this is a simplification, right? There has to be cases where airplanes in the air don't gain the entirety of the wind speed due to wind direction, drag, aerodynmics, etc, right? I'm thinking that if the wind is exactly behind the plane, that less speed will be granted to the airplane due to aerodynmics or something, causing some of the force of the wind to dissipate as it flows past the plane, or that if there's an angle to the wind, there has to be some sort of sine function force pushing up or down on the plane, slowing the overall speed as well. Correct me if I'm wrong please. --Wirbelwindヴィルヴェルヴィント (talk) 21:10, 31 July 2007 (UTC)

Hmm, I'm not entirely sure what you're describing. If the plane is going 500 mph relative to the wind, and the wind is going 100 mph in the same direction as the plane, then the plane is going 600 mph relative to the ground. Or is it that a plane is head north at 500 mph, then a sudden gust of south wind comes in at 100 mph, raising the plane's speed with respect to the ground to 600 mph? I feel like I'm missing something here. (Oh, and no doubt strong winds do have some complicated effects on planes, if only because they alter the air speed over the wings) Skittle 22:11, 31 July 2007 (UTC)

I'd think the actual variations are more the case of wind speed being very much an average. The aircraft itself is flying with respect to the air (not being pushed by the air -- the key point), wholly independent of how the air moves with respect to the ground (or how the ground moves with respect to the sun, etc, etc). It's much the same as the puzzle about the airplane taking off from a treadmill. Wind striking the side of the aircraft is a different case, of course, but I don't think that's really the same thought experiment at all.

To consider the side effect, though -- let's take a 60-unit wind 5° off the bow-stern axis (say, a tailwind) and a 5-unit wind at right angles to the direction of flight. Before we consider the side component, one aircraft travels at X+60 (relative to ground) while the other travels at X. Now, the 5-unit side wind component of the tailwind certainly creates some drag -- say, d(5). That airplane is now moving at X+60-d(5). However, the other airplane suffers the same drag component and travels at X-d(5). Seen only from the frame of reference of the airplanes, though, both merely encounter 5-unit crosswinds. There's no way for airplane 1 to know of the tailwind unless airspeed can be compared with externally-calculated groundspeed. — Lomn 22:18, 31 July 2007 (UTC)

I think the only time it may not be accurate to sum them is very close to the ground (in Ground effect). Even in that case, if there are discrepencies they will be small since the initial condition is a 100 mph wind relative to the ground. Otherwise, it's the relative mostion described above/ --Tbeatty 22:30, 31 July 2007 (UTC)

I don't really know enough here, but I'd think that wind would have nowhere near that effect on it. consider a boat with a sail up - it's not going to go the same speed as the wind, because there's a lot more to it than that. And the airplane's aerodynamics would probably *stop* the wind from helping it too much, the only benefit I'd think there'd be to flying something like a jumbo jet with the wind would be less resistance. Imagine an airplane sitting on a runway, with the wind to it's back, and the wheels in neutral. Surely you wouldn't think the wind there would push it at speed, so why would it happen off the ground? There's still friction involved --Longing.... 22:24, 31 July 2007 (UTC)

This is why I edited in the "key point". A boat moves with respect to water. A car moves with respect to the ground. Air pushes on them as an additional force. An airplane, however, moves with respect to the air. Just as a car on a dynamometer can engage its gears at power and yet not move with respect to an external frame, an airplane can fly into a headwind and remain completely stationary with respect to the ground. Of course, for your specific example, an airplane sitting on the runway is better described as a car. One would similarly classify a minivan in freefall as an airplane and not expect anti-lock brakes to be of any use. — Lomn 22:28, 31 July 2007 (UTC)

Not really. I highly, highly, highly doubt that the friction of having wheels touching the ground would stop the wind from pushing it forward more than a literal wall of air in front of the aircraft. --Longing.... 22:38, 31 July 2007 (UTC)

I can't figure out where you're going with the wall-of-air thing, but the proper analogy to airplane-in-air is boat-in-water, and a boat really does move at speed+current with no appreciable "lot more to it". Talking about the thrust from a boat's sails is analogous to saying that an airplane will never reach the speed of the exhaust coming out the jet engines, which is a different question entirely. — Lomn 00:16, 1 August 2007 (UTC)

Just as a note, I have heard pilots say that our flights would arrive early because of a strong tailwind. The effect might not be large on a small scale but when you are flying cross-country (as I was), perhaps it adds up. The time I remember them saying that we did arrive considerably earlier than we were predicted to, maybe an hour or so. --24.147.86.187 23:44, 31 July 2007 (UTC)

The effect is not at all small on trans continental flights, flightpaths are designed to take as much advantage of jetstream as possible. Vespine 00:22, 1 August 2007 (UTC)

Quite. You have to put up with the winds whether you want to or not. If you pull up timetables for British Airways flights[14] from London (LHR) to New York (JFK), you'll find that the average eastbound flight (to London, travelling with the jetstream) is nearly forty minutes shorter than the average westbound flight (travelling against the prevailing winds). TenOfAllTrades(talk) 01:49, 1 August 2007 (UTC)

Skittle: Lomn was correct in that the plane is moving 500 mph in respect to the air and not to the ground. The 100 mph air would be in respect to the ground, as well as the 600 mph being in respect to the ground. And thanks everyone for helping me clear it up. As a side question though, say you arrive faster than expected due to tailwind, you can use that to directly calculate average tailwind speed, correct? It would be distance divided by time saved equals average tailwind speed, and not something like distance divided by time multiplied by some drag coefficient, right? --Wirbelwindヴィルヴェルヴィント (talk) 03:22, 1 August 2007 (UTC)

Specifically, what you have here is an object moving through a fluid (air counts) when the fluid is moving. As a pilot, they teach you about things like "airspeed" (the airplane's speed relative to the air), "wind speed" (the air's speed, relative to the ground) and "ground speed" (the airplane's speed, relative to the ground.) It turns out that these things do actually just add-up, the way you'd expect.

Imagine a checker board. You move your piece 5 spaces forward ("500 miles North.") In that same amount of time, the wind blows your piece 2 squares over ("200 miles East.") A quick bit of trig will tell you how far you moved, altogether. You don't even need the trig to know that, had the wind blown you 2 more squares North you'd be "700 miles North" from start or, if it were a headwind, you'd be only "300 miles North."

All of the inefficiencies in aerodynamics that have been bugging you since grade school happen before the airplane's original airspeed are calculated. That is, maybe the propeller is turning to push 525MPH of air backwards but, because of drag & whatnot, the airplane is only getting an airspeed of 500MPH. So, while there is loss like your intuition suspects, the part about the airplane going 500MPH through the air still holds.

...In the idealized problem, that is. We can do similar math with real airplanes, though, and it's pretty straightfwd. We ignore propeller/jet slippage and just deal with "true airspeed" (aircraft speed relative to the air.)

Hope that helps! Oliepedia 05:29, 1 August 2007 (UTC)

Back Crack

What happens when you crack your back? Why does it feel good? Is it healthy or dangerous? —The preceding unsigned comment was added by 151.28.233.145 (talk • contribs) 21:24, 31 July 2007 (UTC)

See Wikipedia:Medical disclaimer. - hydnjo talk 22:52, 31 July 2007 (UTC)

And see Cracking joints. --Anon, July 31, 2007, 22:58 (UTC).

Brushing teeth before breakfast

Hi

I've been told that it has been "clinically proven" that brushing your teeth before you have breakfast is better than afterwards. Do you think this is true or false?

Cheers

Aaadddaaammm 22:44, 31 July 2007 (UTC)

depends on who's hype you believe. In theory, some toothpastes might form a 'protective shield' that would protect you from evil breakfast germs. On the other hand, toothpaste has been proven to be almost entirely bullshit, and advertisements are always bullshit. Personally, I'd say to brush your teeth after breakfast and after dinner --Longing.... 22:46, 31 July 2007 (UTC)

Funny, "toothpaste is bullshit" appears no where in our toothpaste article. Though surprisingly there are no citations in the article discussing the purported health benefits. Dragons flight 22:55, 31 July 2007 (UTC)

Well, it isn't an active ingredient... --Longing.... 01:50, 1 August 2007 (UTC)

While many advertisements including toothpaste ones have a lot of bullshit, a claim made in an advertisement that it's been clinally shown that brushing before breakfast is better then after would probably mean there is at least one study that shows this in most developed countries (don't know about the US). It won't necessarily mean that there's been no studies showing the opposite although likely if most studies show that brushing after is better then before and you claim that it's been clinally shown before is better then after you'd be held up for deceptive advertising Nil Einne 12:52, 1 August 2007 (UTC)

See here. [15]

It's not actually bullshit though. Plaque that's 24+ hours old becomes damaging to your teeth. If you can get it away without using toothpaste, be my guest. But I'm going to continue using a small amount when I brush. --Wirbelwindヴィルヴェルヴィント (talk) 03:12, 1 August 2007 (UTC)

Or we could assume that no toothpaste is used at all... In theory, brushing before you eat breakfast would accomplish brushing away any large(relative to bacteria) bacterial colonies that might have popped up overnight. Brushing after would brush away food particles that might lead to bacteria growth until you brush again. Also, brushing after would remove those previously mentioned colonies as well as the food. So let's say X = the time you would have brushed had you brushed before breakfast and Y = the time you would brush after finishing breakfast. Notwithstanding technique or other such variables, it seems that as long as the time between X and Y isn't significant, then brushing after breakfast should accomplish the same thing brushing before would have and more. However, add an antibacterial mouthwash and toothpaste to the party and you'll be cookin' with fire.Mrdeath5493 06:21, 1 August 2007 (UTC)

But there is the added problem that, apparently, brushing your teeth within half an hour of eating can damage the teeth (in the long term, if done frequently) because the enamel is more fragile straight after eating due to the mouth chemistry (pH if I recall) altering. So brushing before eating removes the plaque, so there is nothing for the sugar you eat to stick to, without removing any enamel. It doesn't remove food particles from the meal to come, but then I personally find that makes me retch! Horses for courses... Skittle 20:51, 1 August 2007 (UTC)

August 1

The Nile River

Is there a current consensus about the "true" source of the White Nile? Is it in Rwanda or in Burundi?

Help!!!!!anyone help me anwser this question....i have an exam juz few hours to go....i nid the anwser as quick as possible

this is a practice b4 exam...the question goes like this:

Why do aquatic veterbrates have smaller skeletons than land vertebrates?

although this question might not pop up during the exam but i was curious to noe the anwser... this question was found in the notes given by the teacher.

60.48.92.187 01:38, 1 August 2007 (UTC)zhiting

As the top of the page says, Do your own homework. Although this should be really, really, really obvious --Longing.... 01:48, 1 August 2007 (UTC)

That seems harsh... the questioner isn't asking for help with homework, but with studying. And we don't know his or her age or background. To the questioner: try looking at buoyancy and skeleton. --Allen 01:53, 1 August 2007 (UTC)

It is homework, though. It has nothing to do with age or background, just thinking about it scientifically would lead you to "What's different about these two creatures?" which would you lead you to the obvious answer --Longing.... 01:57, 1 August 2007 (UTC)

Well part of what the class is probably trying to teach them is to "think scientifically" which clearly the poster can't do (how easy it is to forget that we didn't all think scientifically once! how quickly we take as natural what took centuries for humans to develop!). I don't think there's anything wrong with just pointing them in the right direction. --24.147.86.187 02:02, 1 August 2007 (UTC)

And in that direction...try thinking about the purpose of a skeleton, and the different needs the two types of animals would have for anything that fulfilled that purpose. Someguy1221 02:32, 1 August 2007 (UTC)

Too late for the exam now, but is this statement even true? Does it mean as a proportion of body weight? After all, the largest vertebrates are blue whales and their skeletons are enormous! I would suggest though, lightness for buoyancy, and the natural support of the water means not as much strength is needed in the skeleton. Cyta 07:10, 1 August 2007 (UTC)

Cyta: yes. From what I remember talking to a friend (who keeps fish and knows everything anyway), most fish have far less dense or narrower bones than we do, because they're underwater, they don't have to support as much weight. The above link to buoyancy would help here. Although, you are correct, that whales have much much larger skeletons than we do, proportionally. --Longing.... 11:16, 1 August 2007 (UTC)

Blindness from birth affecting how one learns body language, etc.?

I have been searching, including on your pages regarding autism spectrum disorders and congenital blindness, and I'm still a little confused. Is body language something learned through observing others in the first few months of life? And, if it is, how is it that blind people are able to pick up, if not all the visual cues, at least enough nonverbal cues to not be labeled as having a PDD, if they can't see to pick up those cues? Is it the context of a situation that blind and visually impaired people can pick up if they don't have an autism spectrum disorder? Or, do most visually impaired people also lack some social skills based on the fact they'd can't pick up body language well? I know a few, and they seem to be okay with social situations, though of course they have to be told if someone is leaving a room, etc.. I would think the problems with social skills, making friends, etc., with those with autism spectrum problems would be all traced back to the inability to read such langauge.DTF955 02:43, 1 August 2007 (UTC)

I think you are making several quite large assumptions. One factor that you seem not to be taking into consideration is just how highly a sight able person would modify their own behaviour and their body language knowing they are interacting with a blind person. I imagine a person who is aware that their visual queues are not being recognised would most likely offer a more then compensatory lenience in that regard. Vespine 06:07, 1 August 2007 (UTC)

Good point - being partly blind myself, I guess I don't really consider how that would differ fromt he way a sighted person would do it. (Or, maybe I have a PDD :-)

Amesbury Archer had unusual configuration to the bones in his feet.

Apparently the body buried near the Archer is presumed to be a relative because they shared this configuration.

"An analysis of the bones later showed that he and the Archer were related as they both had the same unusual bone structure in their feet – the heel bone had a joint with one of the upper tarsal bones in the foot."

Is there a diagram of what this looked like? How unusual or rather, how common would this be in the human population? Have other examples of this trait been discovered in other ancient skeletons? If so, which ones?

Is this trait common to a particular group of people or region of the world?

Weaver137 03:31, 1 August 2007 (UTC)

It is not clear from the Amesbury Archer article and what's available from the Wessex Archaelogy website exactly what the variation seen is. It appears to involve the calcaneus (heel bone) and navicular, a bone on the instep side of the foot. This is called calcaneonavicular coalition. If it is a complete fusion (synostosis), it is exceedingly rare ( 0.03%). If it is a partial articulation (synchondrosis or syndesmosis), it would occur about 5.6% of people.[16] It is not specific to people from a region, but there is a heritable aspect to their occurrence, especially the 0.03% event. There are radiographic images in the link above, but they are seen from a 45 degree angle, so they look odd. Here are another few images. Flyguy649 ^talk _contribs 05:14, 1 August 2007 (UTC)

I believe that when I saw a scientist describing how they thought they were related, she talked about the condition appearing in only 5% of the population, making it 'likely' that the 2 were related, since they both had it. This points to the 2nd condition that FlyGuy points out. I'm pretty certain of my memory because I remember thinking that it wasnt really very conclusive, although likely. Capuchin 09:55, 1 August 2007 (UTC)

I guess further to my and Capuchin's comments, the chance of two random people found together with this condition is 5%x5% = 0.25%, which is pretty small although not beyond the realms of possibility. The argument that they are related likely has to do not only with this statistical probability, but also with respect to their features. I believe they had the same colour hair. Flyguy649 ^talk _contribs 13:57, 1 August 2007 (UTC)

Wormholes

What is the debate about wormholes? What do scientists and people think about wormholes?Invisiblebug590 04:15, 1 August 2007 (UTC)

Have you read wormhole? --TotoBaggins 04:47, 1 August 2007 (UTC)

The physics pretty much says that they could exist - but we have never found one and we know we couldn't possibly create one - so as a practical matter, they aren't all that interesting. (except of course to SciFi writers!) SteveBaker 10:46, 1 August 2007 (UTC)

I found one yesterday, in an apple of all places. Gzuckier 14:40, 1 August 2007 (UTC)

Had you already eaten half of the apple with no sign of the worm in what remained? Nil Einne 15:42, 1 August 2007 (UTC)

Solar Cells

Hi, just wondering if someone can answer this question (I've had a look at the solar cell article but it doesn't quite make sense. I understand about the n-p junction and the zone of depletion, and what when a photon is absorbed by the semiconductor is produces both an electron and a positive hole (because the electron is promoted to the conduction band, leaving a positive hole in its wake), and that because of the positive/negative charges on the n/p halves the electron will be attracted to the n half and the positive hole will be attracted to the p half. BUT, why do electrons flow through an external circuit, why doesn't the diffusion just occur within the cell, and how come in most diagrams I've looked at the electrons flow through the external circuit from the n to the p half, effectively travelling from a region of conventional high potential to a region of conventional low potential (the opposite direction to which they should be travelling)?. Thanks Guycalledryan 05:02, 1 August 2007 (UTC)

Once the pair has separated, the n side has one more electron and the p side one fewer than before. Since with no current flow (a dark cell) the potential at the two ends of the cell must be the same, with the new arrivals the potential at the n end is now lower than at the p end. Since electrons flow "uphill", an electron at the very end of the n region (there are plenty there!) and a hole from the end of the p region traverse the wire and the load and annihilate somewhere outside the cell. This is simply the path of least resistance: the depletion zone is an insulator, so the restorative current flows through the load instead. --Tardis 15:18, 1 August 2007 (UTC)

human anatomy

some anatomical part that begins with the letter y

See List of subjects in Gray's Anatomy: Alphabetical: Y (plus you might also find some Yersinia bacteria in a human body) and List of acupuncture points has quite a lot that start with y. JMiall₰ 12:31, 1 August 2007 (UTC)

Your arm, your leg, your head, your foot and so on and so forth :P Lanfear's Bane 12:49, 1 August 2007 (UTC)

Y chromosome. FYI, the reason you won't find many such words is that in ancient Greek, from which most English anatomical terms are derived, a word starting with Y was always spoken with a "rough breathing", which means it would be transliterated into our Roman alphabet with an initial "H". This explains why there are so many medical words beginning with "hy" and almost none beginning with "y". --TotoBaggins 13:13, 1 August 2007 (UTC)

yeux (if you're French). Physchim62 (talk) 14:08, 1 August 2007 (UTC)

natural abundance

I need to learn how to compute the natural abundance of an isotope. Anyone wanna share? --MKnight9989 13:49, 1 August 2007 (UTC)

The natural abundance of an isotope is just how much of it is found somewhere (in the universe, in the solar system, on the Earth, in Iowa, etc.). You can't compute it any more than you can compute "how long is a piece of string?"; you just have to measure it. --TotoBaggins 14:08, 1 August 2007 (UTC)

If you don't want to measure it, you can look up terrestrial values in a table such as this one. Physchim62 (talk) 14:12, 1 August 2007 (UTC)

As much as I'd love to, I have to know how to calculate myself for school. Thanks anyway though. --MKnight9989 14:50, 1 August 2007 (UTC)

Using the table linked to by Physchim, Standard Atomic Weight = the sum of [(Relative Atomic Mass of isotope 1(RMA1) x Isotopic Composition of isotope 1(IC1)) + (RMA2 x IC2) + ...]. I'll let you plug in the values, and figure out what you have to do if you are given different variables. Using Helium as an example may be the simplest. Flyguy649 ^talk _contribs 15:13, 1 August 2007 (UTC)

Frog

In Upstate New York in the Catskill Mountains, I often catch and release a kind of frog that are simmilar (but not the same) in shape and colouring to the leopard frog, but much smaller. Anyone have any ideas on what kind of frog it might be? If so, thanks a lot! --Gbgg89 14:48, 1 August 2007 (UTC)

Federal forest service lists the following toads/frogs in the area: American toad, green frog, gray treefrog, northern spring peeper, and Fowler's toad. -- Kainaw^(what?) 14:53, 1 August 2007 (UTC)

There are other frogs found in New York state than listed above. The species closest in appearance to the Leopard Frog (Lithobates pipiens) is the Pickerel Frog (Lithobates palustris). It is similar to the Leopard Frog, but the dark brown spots are more rectangular than circular, and it is smaller with an average body length of 2.5 inches (as opposed to the Leopard that is 3-4 inches). Check out the website at nyfalls.com/wildlife for a complete list of New York amphibians. --Eriastrum 17:04, 1 August 2007 (UTC)

Thank you so much! Yes, the Pickerel Frog is the frog that I have caught there. I have been wondering what it was for a while, so thank you so much! --Gbgg89 20:41, 1 August 2007 (UTC)

residue left when bleach dries

Help please!!!!!

When belach dries it leaves a white crystline residue. My boss wants it removed from painted surfaces, ceramic tile and chrome. Any suggestions that will save minimum paid employees hours and hours of scrubbing uselessly to remove the stuff?

Many thanks on any help that you can give.

Don't you mean The Boss? *joking* Nil Einne 15:29, 1 August 2007 (UTC)

On a more serious note, does ordinary water not work? Perhaps you should try a greater dilution? Nil Einne 15:42, 1 August 2007 (UTC)

It is possible the bleach has etched or corroded the surfaces rather than left a residue. Lanfear's Bane

use a bathroom cleaner such as vim (cleaning product) or flash, cif whatever you call it, plus water - you'll still need to scrub.83.100.138.237 16:39, 1 August 2007 (UTC)

White stuff on old batteries

Are the white crystalline residues on old batteries harmful?

It's probably some of the electrolyte and generally won't be that harmful but I would recommend you wash your hands afterwards and definitely don't lick it. But for more info, you need to say what old batteries? Alkaline? Lead acid (car etc batteries)? NiMH? NiCad? Li-ion? Lithium? Zinc-carbon? Where on the old batteries? Terminals? External covering? On the electrodes (for lead acid batteries)? Nil Einne 15:16, 1 August 2007 (UTC)

Just a regular AA battery. I left them in my wireless mouse for long after they were dead. The stuff was most abundant around the metal +/- things where the batteries connect to the device. Some actually creeped outside the battery container. 128.163.224.198 16:29, 1 August 2007 (UTC)(original poster)

If they were alkaline it's probably potassium carbonate - slightly corrosive and not for eating as said above, it's a good idea to clean it out of your mouse (use wet rag, then dry) as it can encourage further corrosion of the terminals. No more harmful than strong floor cleaner...83.100.138.237 16:37, 1 August 2007 (UTC)

Entry of blood from marrow to circulatory system

How does blood generated in bone marrow enter into the circulatory system? Morton00 16:46, 1 August 2007 (UTC)

Bones aren't simply dead things; they contain a matrix of living cells and these cells have the usual blood supply that connects with the rest of the circulatory system. So marrow cells also have access to the circulatory system.

Atlant 17:15, 1 August 2007 (UTC)

Understood. It's the path that the blood takes that I wonder about. Is the bone porous enough? Do arteries and veins enter the bone at some point?

Bones are filled with blood vessels. They travel in longitudinal and transvers "canals". See images at Bone#Macrostructure, for example. Flyguy649 ^talk _contribs 19:24, 1 August 2007 (UTC)

How many human diseases are there?

Any numbers/estimates?128.163.224.198 16:58, 1 August 2007 (UTC)

A way to get an estimate is to look at ICD9 codes. They codify each disease and subsection of diseases. If you can find a count of how many ICD9 (or ICD10) codes there are, you'll have an estimate for the number of diseases. -- Kainaw^(what?) 17:04, 1 August 2007 (UTC)

Trolleybus/Trackless Trolley

Can a trolleybus run off from underneath the transmission wires above? What happens if this occurs? How is it reattached to the electrical distribution system? Thanks. - MSTCrow 19:02, 1 August 2007 (UTC)

It happens frequently, often at junctions for the wires, IIRC. The bus stops quickly, the driver gets out and replaces the trolley poles onto the wire. (there are spring-loaded ropes at the back of the trolley that attach to the poles that the driver uses to pull down and move the poles. You can see them in this Image:Translink-2744.jpg) Because there are two poles, one is usually stowed first. It takes about a minute. Flyguy649 ^talk _contribs 19:18, 1 August 2007 (UTC)

Type of thought disorder?

I was wondering if there was a recognized type of thought or general disorder where the afflicted had uncontrollable thoughts. The types of thoughts could include reoccurring phrases and other things that annoy the afflicted person or that they disagree with. Sorry for the ambiguity. --74.97.142.249 20:30, 1 August 2007 (UTC)

There's a WP article on intrusive thoughts. Haven't read it myself. --Trovatore 20:34, 1 August 2007 (UTC)

Thanks Trovatore, that seems like a good place to start. --74.97.142.249 20:54, 1 August 2007 (UTC)