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{{future album}}
[[Category:Non-talk pages that are automatically signed]]{{User:Froth/speedyS}}<!--{{Wikipedia:Reference desk/header|WP:RD/S}}-->
{{Infobox Album <!-- See Wikipedia:WikiProject Albums -->
|Name = Theater of the Mind
|Type = studio
|Artist = [[Ludacris]]
|Cover = Theater Of The Mind.png
|Released = {{Start date|2008|11|25}}
|Recorded = 2007–2008
|Genre = [[Southern rap]]
|Length =
|Label = [[Disturbing tha Peace]], [[Def Jam Recordings|def Jam]]
|Producer = [[DJ Premier]], [[9th Wonder]], [[Clinton Sparks]], [[Dre & Vidal]], Ice Drake, [[Don Cannon]],<ref name=buzznet/> [[Kanye West]], [[Swizz Beatz]], [[Just Blaze]], [[Darkchild]], [[Ski (producer)|Ski]], [[Organized Noize]], [[DJ Toomp]], [[Drumma Boy]]
|Reviews =
|Last album = ''[[Release Therapy]]''<br/>(2006)
|This album = '''''Theater of the Mind''''' <br/>(2008)
|Next album =
{{Singles
|Name = Theater of the Mind
|Type = studio
|single 1 = [[What Them Girls Like]]
|single 1 date = August 7, 2008
|single 2 = [[Wish You Would]]
|single 2 date = September 2, 2008
|single 3 = Undisputed
|single 3 date= September 30, 2008
}}}}


'''''Theater of the Mind''''' is the sixth upcoming [[studio album]] by [[United States|American]] rapper [[Ludacris]]. It is scheduled to be released on November 25, 2008.<ref>[http://www.defjam.com/site/artist_news.php?artist_id=308&news_id=106324 Ludacris official website]</ref>
{{Wikipedia:Reference_desk/Archives/Science/2007 October 27}}


==Background==
{{Wikipedia:Reference_desk/Archives/Science/2007 October 28}}
The album was slated for release on October 21, but was pushed back to November 25. In April 2008, a song named "Stay Together" appeared on xxlmag.com;<ref>[http://www.xxlmag.com/online/?p=20680 Ludacris "Stay Together" audio.]</ref> supposedly from the new album. [[DJ Toomp]] has also worked on this album.<ref>[http://www.xxlmag.com/online/?p=19317 DJ Toomp: Grammy Family]. Accessed July 6, 2008.</ref> [[T.I.]] will also be appearing on a track called "Wish You Would".<ref name=wishyouwouldmtv>[http://www.mtv.com/news/articles/1592463/20080808/ludacris.jhtml Ludacris, T.I. 'Wish You Would' Believe There's No Beef Between Them.] Accessed August 8, 2008.</ref>


The first single "[[What Them Girls Like]]" was released on August 7, 2008. The single "co-stars" [[Chris Brown (entertainer)|Chris Brown]] and [[Sean Garrett]].
{{Wikipedia:Reference_desk/Archives/Science/2007 October 29}}


The second single "[[Wish You Would]]" was released on September 2, 2008. The single "co-stars" T.I.
= October 30 =


A video for the song "Undisputed" has been made and first shown on the BET Network. The video features boxer [[Floyd Mayweather, Jr.]] and 6-year old boxer Pretty Boy Bam Bam.<ref name=undisputed>ATLien (September 8, 2008). [http://straightfromthea.com/2008/09/08/video-ludacris-vs-a-6-year-old Video ~ Ludacris vs. a 6 Year Old] ''Straight From the A''. Accessed September 8, 2008</ref>
== Protein domain ==


==Concept==
Two different protein domains can have a same function why or why not?
Ludacris says the album is [[theatre|theatrical]], conceptual-wise. Every song you hear sounds like a [[scene (film)|scene]] from a [[film|movie]].<ref name=rapup>(July 16, 2008). [http://www.rap-up.com/2008/07/16/ludacris-gets-theatrical-on-sixth-album/ Ludacris Gets Theatrical on Sixth Album] ''Rap-Up''. Accessed August 3, 2008.</ref>


==Guests==
If I consider two amino acid sequences of a protein with same domains but changes in 2 or 4 amino acids in the chains. Could it have the same function?
Ludacris stated that none of the tracks will be featuring any guests, instead they will be "co-starring".<ref name=wishyouwouldmtv/> Confirmed co-stars include [[Lil Wayne]], [[Floyd Mayweather Jr.]], [[Jamie Foxx]], [[The Game (rapper)|The Game]]<ref name=complexludainterview>[http://www.complex.com/CELEBRITIES/Web-Exclusive/Ludacris?page=2 Ludacris Interview.]</ref>, [[T.I.]], [[Chris Brown (singer)|Chris Brown]], [[Nas]], [[Chris Rock]], [[Common (rapper)|Common]], [[Sean Garrett]], [[T-Pain]], [[Plies (rapper)|Plies]], [[Rick Ross (rapper)|Rick Ross]], [[Spike Lee]], [[Playaz Circle]], Willy Northpole<ref name=billboardludacrissept2>[http://www.billboard.com/bbcom/news/article_display.jsp?vnu_content_id=1003844677 Ludacris' Busy Fall: New Album, Two Films.] Accessed September 2, 2008.</ref>, [[Criss Angel]]<ref>[http://www.defjam.com/site/artist_news.php?artist_id=308&news_id=106324 Ludacris official website]</ref> and more. The rock band [[Good Charlotte]] is planned to have an appearance.<ref name=buzznet>[http://www.buzznet.com/musicnews/j2282381/ Ludacris Acts Out on September's 'Theater of the Mind']</ref> Ludacris' fellow [[Disturbing tha Peace]] artist, Willy Northpole is scheduled to co-star with [[The Game (rapper)|The Game]].<ref name=bet>Low Key ([[July 17]], [[2008]]). [http://blogs.bet.com/music/soundOff/the-ludacris-experience/ The Ludacris Experience…] ''BET''. Accessed August 3, 2008.</ref> He hopes to work with [[Eminem]] for the album.<ref name=billboardludacrissept2/>


==''The Preview''==
Respected teacher
Ludacris released a "Gangsta Grillz" mixtape with [[DJ Drama]] called ''[[The Preview]]''. The mixtape was released as a download on July 28, 2008.


==Confirmed tracks==
My problem is that I considered 2 chains of the same protein
{|class="wikitable"
|-
!Title
!Featured guest(s)
!Written by
!Producer(s)
!Length
|-
|"Call Up the Homies"<ref name=billboardludacrissept2/>
|[[The Game (rapper)|The Game]] & Willy Northpole
|C. Bridges, J. Taylor, W. Adams
|[[Clinton Sparks]]
|4:06
|-
|"Do the Right Thing (Wake Up)"<ref name=hiphopchronical>http://www.thehiphopchronicle.com/2008/09/18/ludacris-speaks-to-the-hip-hop-chronicle-videoaudio Ludacris Speaks to Hip Hop Chronicle</ref>
|[[Common (rapper)|Common]] & [[Spike Lee]]
|C. Bridges, L. Lynn, S. Lee
|[[9th Wonder]]
|
|-
|"Everybody Hates Chris"<ref>[http://blogs.sohh.com/atlanta/2008/09/gyants_honorabl.html Gyan's Honorable Mention]</ref>
|[[Chris Rock]]
|C. Bridges, D. Cannon
|[[Don Cannon]]
|
|-
|"I Do It For Hip Hop"<ref name=ludacrisangie>[http://videos.onsmash.com/v/LyarCzjWtcuXwZUj Angie Martinez Interviews Ludacris.]</ref>
|[[Nas]]
|C. Bridges, N. Jones, J. Smith
|[[Just Blaze]]
|-
|"Last of a Dying Breed"<ref name=billboardmind/>
|[[Lil Wayne]]
|C. Bridges, D. Carter, C. Gholston
|[[Drumma Boy]]
|
|-
|"Let's Stay Together"<ref name=billboardludacrissept2/>
|
|C. Bridges, P. Beauregard
|[[DJ Paul]]
|4:18
|-
|"MVP"<ref name=billboardmind>Hillary Crosley (September 26, 2008). [http://www.billboard.com/bbcom/news/article_display.jsp?vnu_content_id=1003855663 Ludacris Lets Listeners Inside His 'Mind'] ''Billboard''. Accessed September 26, 2008.</ref>
|
|C. Bridges, C. Martin
|[[DJ Premier]]
|
|-
|"One More Drink"<ref name=billboardludacrissept2/>
|[[T-Pain]]
|C. Bridges, F. Najm
|[[Trackmasters]]
|3:43
|-
|"Southern Gangsters"<ref>[http://www.defjam.com/site/artist_news.php?artist_id=308&news_id=106296 Listen In On The Ludacris Theather of the Mind Conference Call]</ref>
|[[Playaz Circle]] & [[Rick Ross (rapper)|Rick Ross]]
|C. Bridges, T. Epps, E. Conyers, W. Roberts
|
|-
|"Undisputed"<ref name=undisputed/>
|[[Floyd Mayweather]]
|C. Bridges, F. Mayweather
|Don Cannon
|4:36
|-
|"[[What Them Girls Like]]"<ref name=bet/>
|[[Chris Brown (singer)|Chris Brown]] & [[Sean Garrett]]
|C. Bridges, C. Brown, S. Garrett, R. Jerkins
|[[Rodney Jerkins|Rodney "Darkchild" Jerkins]]
|4:06
|-
|"[[Wish You Would]]"<ref name=wishyouwouldmtv/>
|[[T.I.]]
|C. Bridges, C. Harris, A. Davis
|[[DJ Toomp]]
|4:50
|}


==References==
Chain A ---> n l i i l a n n s l s s " n g n v" t e s g c k e c e e l e e k n i k e f l q s f v h i v q m f i n " t s "
{{reflist}}


{{Ludacris}}


[[Category:Albums produced by 9th Wonder]]
Chain B ---> n l i i l a n n s l s s " n g n " v t e s g c k e c e e l e e k n i k e f l q s f v h i v q m f i n t s
[[Category:Albums produced by Darkchild]]
[[Category:Albums produced by DJ Premier]]
[[Category:Albums produced by DJ Toomp]]
[[Category:Albums produced by Eminem]]
[[Category:Albums produced by Just Blaze]]
[[Category:Albums produced by Kanye West]]
[[Category:Albums produced by Swizz Beatz]]


[[fr:Theater of the Mind]]
Those in double Inverted commas are excluded from the domain chain but they are considered in the same domain why? <small>—Preceding [[Wikipedia:Signatures|unsigned]] comment added by [[User:Biomedicalpersonal|Biomedicalpersonal]] ([[User talk:Biomedicalpersonal|talk]] • [[Special:Contributions/Biomedicalpersonal|contribs]]) 05:12, 30 October 2007 (UTC)</small><!-- Template:Unsigned --> <!--Autosigned by SineBot-->

::I do not understand what you are trying to ask in the second part of your question but I may be able to help you with the first part. A few amino acid changes in non-critical regions or mutations resulting in similar amino acids (see [[Neutral mutation]]) in critical regions may not cause measurable effect on the functioning or the interactions of the protein domain. It would help if you clarify the second part of your question about protein chains. By the way, these appear to be homework questions. The users on the reference desk are not supposed answer your homework questions, but if you have do not understand a concept or need help getting pointed in the right direction by all means ask away. [[User:71.226.56.79|71.226.56.79]] 04:22, 31 October 2007 (UTC)

== food poisoning ??? ==

{{rd-deleted}}This question was removed for a reason. We cannot offer medical advice on either poisoning or allergies. If you are worried about the state of your friends health you should consult a medical professional immediately, especially if you believe she has been poisoned. Discussing it on the internet first should not be your immediate priority. '''<font color="SteelBlue">[[User:Lanfear%27s_Bane|Lanfear's Bane]]</font> | <font color="DimGray">[[User_talk:Lanfear%27s_Bane|t]]</font>''' 21:41, 30 October 2007 (UTC)

== production of particles by pair production method . ==

in the wikipedia article "pair production" only example of electron-positrion pair production is given .
is it possible to produce particles like proton , neutron and neutrino by pair production method ? <small>—Preceding [[Wikipedia:Signatures|unsigned]] comment added by [[User:Shamiul|Shamiul]] ([[User talk:Shamiul|talk]] • [[Special:Contributions/Shamiul|contribs]]) 12:30, 30 October 2007 (UTC)</small><!-- Template:Unsigned --> <!--Autosigned by SineBot-->

:Neutrinos and antineutrinos can be produced from a [[photon]].[http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6TVN-4JWMSCS-2&_user=10&_coverDate=06%2F15%2F2006&_rdoc=1&_fmt=&_orig=search&_sort=d&view=c&_acct=C000050221&_version=1&_urlVersion=0&_userid=10&md5=c34f6dd90bfde436c8f6041081ece3f4] Like electron-positron pair production needing other particles involved in order to conserve [[energy]] and [[momentum]], neutrino-antineutrino production from a photon needs other particles involved in order to conserve [[spin]], which is a form of [[angular momentum]].

:[[Protons]] and [[neutrons]] aren’t [[elementary particles]], but instead [[bound states]] of [[quarks]]. So in [[quantum chromodynamics]], low-order particle interactions would include pair production of quarks, not of protons or neutrons. A quark and its antiquark can be produced from a [[gluon]].[http://www.physicsforums.com/showthread.php?p=955414] [[User:MrRedact|MrRedact]] 21:02, 30 October 2007 (UTC)

::While these predictions from theory are very likely correct, we are currently far from being able to experimentally confirm pair production of [[neutrino]]s (because our neutrino detectors are not very sensitive). [[User:Icek|Icek]] 01:08, 31 October 2007 (UTC)

:::Somehow my previous answer to this question has been removed? However there is no neutrino pair production. They are electrically neutral and as such do not couple to [[photons]]. The nearest equivalent would be production of a neutrino/anti-neutrino and corresponding anti-lepton/[[lepton]] from a [[w particle]]. MrRedact is right about quarks being pairproduced, but note they can also be produced from photons as well as gluons (they are charged). Pair production of protons/neutrons is nigh on impossible, when quarks are pair produced they hadronise into two [[Jet (particle physics)|jets]] of particles and protons/neutrons maybe included in the jets. [[User:Cyta|Cyta]] 08:56, 1 November 2007 (UTC)
:::Actually I may have been hasty to dismiss the original answer I didn't spot a link had been provided. The pair production of neutrinos seems only to happen in dense matter, which seems to me a different effect. There is no direct neutrino-photon coupling in the standard model. I suspect the matter is required as there is an intermediate stage in the reaction. [[User:Cyta|Cyta]] 09:00, 1 November 2007 (UTC)

== Anomalous hair ==
'''REMOVED'''. <small>—Preceding [[Wikipedia:Signatures|unsigned]] comment added by [[Special:Contributions/193.188.46.61|193.188.46.61]] ([[User talk:193.188.46.61|talk]]) 13:23, 30 October 2007 (UTC)</small><!-- Template:UnsignedIP --> <!--Autosigned by SineBot-->
:('''EC''') '''Do not request regulated professional advice'''. ''If you want to ask advice that "offline" would only be given by a member of a licensed and regulated profession (medical, legal, veterinary, etc.), do not ask it here. Any such questions may be removed. See Wikipedia:Medical disclaimer and/or Wikipedia:Legal disclaimer. Ask a doctor, dentist, veterinarian or lawyer instead''. Sorry, even a query that sounds innocuous should be addressed to a professional. '''<font color="SteelBlue">[[User:Lanfear%27s_Bane|Lanfear's Bane]]</font> | <font color="DimGray">[[User_talk:Lanfear%27s_Bane|t]]</font>''' 13:32, 30 October 2007 (UTC)
::'''REMOVED'''. --[[User:JWSchmidt|JWSchmidt]] 14:55, 30 October 2007 (UTC)
:::The original question did not ask for medical advice. My original comment made this point. There was no reason to delete my original comment. --[[User:JWSchmidt|JWSchmidt]] 18:23, 30 October 2007 (UTC)
::'''REMOVED'''. --[[User:Mareino|M]][[User_talk:Mareino|<font color="orange">@</font>]][[User:Mareino|r]][[Special:Contributions/Mareino|<font color="orange">ē</font>]][[User:Mareino|ino]] 15:03, 30 October 2007 (UTC)

Per Lanfear's Bane's comment, we cannot offer medical advice. In this case, the original poster was seeking a diagnosis--the identification of the cause of a particular symptom. If someone would like to discuss in more detail why this constitutes a request for medical advice, please bring it to the Ref Desk talk page: [[WT:RD]]. [hidden unsigned comment by [[User:TenOfAllTrades]] made public for clarity]

I am appalled at this continuing deletionism by people who are apparently incapable of telling the difference between a request for an explanation of a biological phenomenon and a request for medical advice. To take this behaviour to its logical conclusion would result in the prohibition of any question relating to human biology (or animal biology for that matter). What causes blue eyes? What causes grey hair? Why does alcohol abuse cause liver damage? All are questions relating to biological phenomena - just as is "What causes an observed variation in human body hair types in humans?" Hiding comments about the removal of questions is also profoundly unhelpful. [[User:DuncanHill|DuncanHill]] 15:20, 30 October 2007 (UTC)

::::One clear sign of a question that we aren't allowed to answer is one that starts off "I have ''some symptom''..." or "A friend has ''some symptom''...". This is quite clearly one of those - and we aren't allowed to answer it - period. The questions you put up as strawmen are not the problem here. I would like to turn this around and ask [[User:DuncanHill|DuncanHill]]: "What kinds of question do you think the ban on giving medical advice is intended to cover?" - clearly it covers something or it wouldn't be there. What? Give me some examples. [[User:SteveBaker|SteveBaker]] 16:38, 30 October 2007 (UTC)

:::Why don't we stop wasting energy here now and instead just send the questioner to [[Wikipedia:Reference desk/Archives/Science/2007 October_23#Anomalous hair|where he asked the same question a week ago]] (8 times in fact). [[User:DMacks|DMacks]] 15:16, 30 October 2007 (UTC)

:Hey, can ''everyone'' confine metadiscussion to the [[WT:RD|talk page]] of the Ref Desk? This sort of debate about what questions are appropriate doesn't belong out on the Desk itself. [[User:TenOfAllTrades|TenOfAllTrades]]([[User_talk:TenOfAllTrades|talk]]) 16:52, 30 October 2007 (UTC)
*"can everyone confine metadiscussion to the talk page" <-- If content is removed from this page because it contains descriptions of personal health matters, then say ''THAT'', but do not say that someone asked for medical advice when they never did. --[[User:JWSchmidt|JWSchmidt]] 18:20, 30 October 2007 (UTC)

*Hey, why was ''my'' comment removed? All I said was that the original question did not seek medical advice. And that continues to be my opinion. The question was not describing a [[symptom]] -- "a sensation or change in health function experienced by a patient" -- because there was no implication that the questioner's health was affected. They were just curious about [[Hair follicle]]s, a subject on which the Wikipedia article is B-class at best. --[[User:Mareino|M]][[User_talk:Mareino|<font color="orange">@</font>]][[User:Mareino|r]][[Special:Contributions/Mareino|<font color="orange">ē</font>]][[User:Mareino|ino]] 04:23, 31 October 2007 (UTC)

This is plainly ridiculous! The sense of this regulation is to avoid unqualified suggestions to be accepted and considered professional by the user. How should this do any type of damage what so ever? If you apply that definition about a symptom it can be eligible to all sorts of things, to nausea due to boat movements for ezample. Aren't you allowed to explain the processes that occur in that event?! Laws and regulations should be implemented only when they make some type of logical sense. You're just tking it to the extreeme here.[[User:193.188.46.254|193.188.46.254]] 13:56, 31 October 2007 (UTC)

== Membrane Potentials ==

What is the difference between membrane potentials, diffusion potentials and nernst potentials. I understand membrane pot. = diffusion pot. and nernst pot. to be when the electrical force opposes the concentration force.?
:In biology, a [[membrane potential]] is the electric potential difference across a membrane of a cell or an organelle such as a [[mitochondrion]]. For charged ions there can be a balance between movement across a membrane due to diffusion and movement due to the electric potential across the membrane: see [[reversal potential]]. If you had a membrane and only one ion was able to cross it by passive diffusion then at equilibrium the membrane potential would be equal to the diffusion potential of that ion: [[Nernst equation#Nernst Potential|Nernst Potential]]. --[[User:JWSchmidt|JWSchmidt]] 14:29, 30 October 2007 (UTC)
::Thanks for the quick reply. I have a slightly better understanding now but still wich to clear some issues [this is in the context of the establishment of an RMP]. 1) Does the term diffusion potential apply to an ion or membrane? 2) Could the Nernst potential (equilibrium potential) be described as the potential difference required to prevent net diffusion of that ionic species? (and how is Nernst potential related to diffusion potential?) 3) What is the purpose of the Na/K ATP'ase (it contributes slightly by reducing RMP; is its primary function to repolarise?). Thanks.
::[ATP'ase] I thought a bit more and reasoned that the purpose may be to create the diffusion potential? or allow the tissue to become excited (function)? i.e. to maintain concentration gradient thereby preventing the Nernst potentials for each ion (Na/K) being reached (a scenario where membrane potential- or is that diffusion potential- is a result of only Na and K)
:::Did you find [[Resting potential]]? For most cells, the [[Na+/K+-ATPase]] is not thought to make a major contribution to the resting membrane potential. The resting potential of many cells is close to the [[equilibrium potential]] of potassium ions (K<sup>+</sup>). Many cells have potassium "[http://ajpcell.physiology.org/cgi/content/full/291/1/C138 leak]" channels that control the resting potential. --[[User:JWSchmidt|JWSchmidt]] 18:13, 30 October 2007 (UTC)

== When will oil run out? ==

Based on world wide consumption trends, and ignoring that it takes millions of years to produce more oil. [[User:64.236.121.129|64.236.121.129]] 16:04, 30 October 2007 (UTC)
:It will never "run out" - but it will become far too expensive to use as fuel. When? See [[Peak oil]]. Cheers [[User:Geologyguy|Geologyguy]] 16:06, 30 October 2007 (UTC)

::I did some calculations in response to an earlier question - the answer is that if we were to carry on consuming it at the present rate, it would run out in about 500 to 600 years. However, if we actually did that, the CO2 levels in the atmosphere would be far beyond "mere" global warming problems - they'd be at a point where humans (and most animals) couldn't breathe. However, the assumption that we'll carry on using it at present levels is flawed. I don't think that running out is a practical proposition. Even if we somehow managed to 'sequester' the CO2, we would only have to halve our consumption every 250 years in order to make the stuff last forever. Another issue is that these numbers for oil reserves are always accompanied by a caveat that says "economically retrievable" - in other words, the only things the oil companies care about is the stuff they can dig up for less than they can sell it for. There are reserves of stuff like "oil shale" that contain a lot of oil - but which are so expensive to dig up and refine that it's not worth doing it. If the oil were ever seriously likely to run out, then the price would go through the roof and suddenly oil shale (or whatever) would be worth exploiting and our reserves would increase (although the price would still be astronomical by today's standards). However, we must stress that with what we know about global warming, it's all completely irrelevent. We must not ever come even close to running out - because even a tenth of that amount of oil - when converted to CO2 - would kill the planet. [[User:SteveBaker|SteveBaker]] 16:28, 30 October 2007 (UTC)

:::Our article on [[world energy resources and consumption]] says that the world's oil reserves are 5.7x10<sup>22</sup> J, and annual oil consumption in 2005 was 1.8 x 10<sup>20</sup> J, so this gives a ratio of reserves to consumption of over 300 years. However, as Geologyguy and SteveBaker have pointed out, this is a rather meaningless figure. In reality oil prices will rise, and oil consumption will fall as alternative energy sources become more economically attractive, and global warming imposes a shorter deadline on us anyway. [[User:Gandalf61|Gandalf61]] 16:44, 30 October 2007 (UTC)

:::Perhaps by then we will have made advances in [[Carbon dioxide scrubber|scrubber]] technology, and have them on every car, big ones atop every building, and just generally all over the place. I mean, once it comes down to economy vs. survival... [[User:Arakunem|<b>Arakunem</b>]][[User talk:Arakunem|<small><sup>Talk</sup></small>]] 17:18, 30 October 2007 (UTC)

::::The chemistry of scrubber technology is not very promising - the kinds that merely absorb CO2 will give the gas up again fairly easily and the substances that react with CO2 to actually get rid of it require lots of energy to make in their own right - so you end up needing more scrubbers to scrub the output of the factory that makes the scrubbers (or the power station that drives it) than the factory itself can make. It's really a bad idea to pin one's hopes on such things because it distracts from the very critical thing of cutting CO2 production in the first place. The whole "Clean Coal" campaign (which has to rely on science-fiction "carbon sequestration" techniques) is a particularly bad example of this kind of wishful thinking. [[User:SteveBaker|SteveBaker]] 03:40, 31 October 2007 (UTC)

:::::Are you saying that collecting and burying CO2 from a coal plant won't work and will use more energy than you get from the coal?--[[User:Dacium|Dacium]] 05:47, 31 October 2007 (UTC)

:::::::Yes and no. I'm saying that on small scales, it takes more energy than you get - and on large scales there isn't a viable technology for doing it at all. Not one single large scale CO2 removal/sequestration plant exists anywhere in the world - not even experimentally. (Which hasn't stopped the US from licensing the building of "Clean Coal" power stations - which is a scandal just waiting to get media attention!) Our article on [[Carbon capture and storage]] explains that what we're likely to have will remove 80 to 90% of the CO2 from the gasses and consume 10% to 40% more energy. But the biggest problem is what you do with the stuff once you've captured it. Sequestering it into limestone requires 180% more energy - so that isn't going to fly. If you try to sequester the CO2 without chemically converting it to something else then you've still got to find a place to store millions of tons of something that's a gas at normal temperatures and pressures. That's no easy task. You can't store it underground or underwater because there isn't enough space at normal temperatures and pressures (If you burn a cubic meter of oil or coal - you get a LOT more than a cubic meter of CO2 as a result! So pumping it into disused coal mines and oil wells isn't going to work for very long.) If you compress the CO2 so it takes up less space (eg storing it as dry ice), then that requires either very high pressure storage or very low temperatures. Either of those technologies will require yet more energy - and worse still, will be vulnerable to long term corrosion and other damage - so you're just building up more trouble for the future. There is talk of dissolving the stuff into saline aquifers or deep oceans - but those are not permenant solutions (eventually, the CO2 would get out again) and the resulting carbonic acids would likely do untold amounts of damage to the environment. Dealing with radioactive waste from a nuclear power plant is EASY by comparison because so little material is involved. So, no, we aren't going to be doing this if we want to save the planet. We have to cut down our consumption (probably the easiest thing to do in the short term) and switch rapidly over to nuclear and (where possible) wind/solar/tidal power until we figure out how to make fusion reactors that actually work. [[User:SteveBaker|SteveBaker]] 18:00, 31 October 2007 (UTC)

::::::On the scales you are talking about, I would imagine there would be nowhere near enough suitable locations to bury CO2 and be reasonably sure that it won't escape at some point in the future. Hopefully within 300 years we will have managed to develop alternatives to fossil fuels, otherwise our pathetic species probably doesn't <I>deserve</I> to survive. [[User:Bistromathic|Bistromathic]] 16:41, 31 October 2007 (UTC)

== Quantum foam ==

I was thinking about [[Quantum foam]] last night. Since particle/antiparticle pairs emerge out of the vacuum - and since there is no "rest frame" - it seems like the particle pairs must be travelling at random velocities relative to my motion. This implies that they have random kinetic energy relative to my motion - which means some of them must be arbitarily energetic. How come we don't measure them? Even though they only last for a spectacularly short amount of time in their own frame of reference - in mine, they'd spend an eternity recombining. Our article briefly sketches over that. [[User:SteveBaker|SteveBaker]] 16:45, 30 October 2007 (UTC)

:You are taking the idea of [[virtual particle]] pairs too literally. Quantum foam is a broad term for the fluctuating nature of space-time at a quantum level that theory demands. Those fluctuations are abstractly described as virtual particles, but from the practical point of there are no particles. Imagine a tablecloth with marbles on it. The marbles may move because they are hit by other marbles, or they may move because the tablecloth shakes. If all you could ever see were the motions of marbles, you might try to explain the motions caused by shaking in the tablecloth as being caused by invisible "virtual" marbles. What is going on in physics is similar. The ways that real particles are affected by the quirks of the vacuum can be usefully described by replacing the vacuum with infinite numbers of virtual particles constantly bombarding matter. However, those particles don't really come from anywhere or go anywhere. They don't have an existence that one could isolate and interact with individually. Really, they are collectively just a way of describing the manifestations of the complicated quantum mechanics intrinsic to space-time. [[User:Dragons flight|Dragons flight]] 19:55, 30 October 2007 (UTC)

:Steve, "quantum foam" does not refer to the virtual particle/antiparticle pairs in the quantum vacuum in general, but specifically to what happens around the [[Planck scale]], where spacetime becomes quantum mechanical. The short answer to any question about quantum foam is that we don't know anything about it at all. But I think you're asking about the quantum vacuum in general, so let's step back from solving quantum gravity and consider something more manageable. Take QED or [[Klein-Gordon equation|Klein-Gordon theory]]. You asked "How come we don't measure them?", referring to virtual pairs with arbitrarily large energies. OK, how do you want to measure them? You would have to interact with them somehow. That means that instead of a [[:Image:Vacuum bubble.png|vacuum-bubble diagram]], you have to consider diagrams with external vertices, and [[:Image:Disconnected.svg|virtual particle loops]] inside. One way to think about these diagrams is that your real external particles are encountering the virtual particles from the vacuum; and they can indeed have arbitrarily large momentum and energy. In many quantum field theories, these loop contributions cause all calculations to come out infinite. Similarly, the vacuum diagrams can cause the vacuum energy to come out infinite. To get something physically sensible, you have to [[renormalization|renormalize]] the theory, and "renormalize" the vacuum energy by zeroing out the infinite offset. So even if you never observe the virtual particles as discrete events, they are hugely significant in every interaction between particles! In some theories, like [[supergravity]], the case is even worse than that, and renormalization doesn't work. Because all of this is not very intellectually satisfactory, we ''hope'' that there is some real, underlying physics that doesn't have these problems. [[Supersymmetry]] takes care of the infinite vacuum energy, but still needs renormalization. [[Superstring theory]] attempts to avoid the need for renormalization at all. But now we're back in the realm of speculations about quantum gravity. --[[User:Reuben|Reuben]] 21:49, 30 October 2007 (UTC)

== Why don't they put some kind of grating over jet engine intakes to prevent birds from getting sucked in? ==

Why not? [[User:64.236.121.129|64.236.121.129]] 16:57, 30 October 2007 (UTC)

:It probably doesn't happen all that often and may actually cause too much disruption to the air intake on the engines. Also, birds would still (I imagine) be sucked and stuck to the grating over the intake. -- [[User:Macaddct1984|MacAddct1984]] 17:05, 30 October 2007 (UTC)

:Per MacAddct, a grating would seriously disrupt the airflow into the engine, creating a tremendous amount of drag. (Remember that air is flowing through the engine at several hundred kilometers per hour.) Plus, what if the bird strike actually damages the grating? In addition to having a bird in the turbine, you'd get all those jagged metal bits of broken grating.... [[User:TenOfAllTrades|TenOfAllTrades]]([[User_talk:TenOfAllTrades|talk]]) 17:12, 30 October 2007 (UTC)

::No - there is no grating - but there is a requirement to test engines for bird strike damage. They actually have an air-powered cannon to shoot birds into running jet engines in order to test them. However if you fly at high speeds and lower altitudes (where birds tend to be) - and if you hit a big one - you can certainly throw a turbine blade and utterly trash the engine in the process. If you have a strong stomach - read [[Bird strike]] which has some exceptionally grisley photographs of the effects of birds on airplanes and airplane engines in particular. [[User:SteveBaker|SteveBaker]] 17:35, 30 October 2007 (UTC)

:Yep. Even with a no-drag indestructible grating, you're still talking about smashing a bird into something at several hundred miles per hour. It's not that the engine is sucking in birds from all directions, just that the plane and bird are hitting -- and even with a grating, the engine still has to generate the same suction. But as SteveBaker said, there's a bird strike test, so a grating is superfluous. &mdash; [[User talk :Lomn|Lomn]] 18:18, 30 October 2007 (UTC)

: A bird running into a turbine is usually not dangerous. The bird will be ripped apart. If the turbine does throw a peice and destroy itself, all that happens is that fuel will continue to be pumped in and a massive flame will come out the back because the fuel is being burned. Obviously you get no thrust from the engine, but the plane can still fly. I don't think any commercial airliners have been brought down, many have had engines taken out.--[[User:Dacium|Dacium]] 05:43, 31 October 2007 (UTC)

::According to [[Bird strike]]: ''according to the FAA only 15% of strikes (ICAO 11%) actually result in damage to the aircraft''. But you're wrong about commercial airliners - there is at least one instance: [[Eastern Air Lines Flight 375]] flew into a a flock of small birds that took out three out of the four engines at once - at the critical moment just after take-off when the engines were at full power - they also splattered over the windshield - blocking the pilot's view and clogged the pitot tubes, preventing them from knowing their airspeed. They didn't stand a chance - the plane rolled over and smashed into the ocean - there were 62 fatalities out of 72 people aboard. Our article on bird strikes also says: ''the problem costs US aviation 600 million dollars annually and has resulted in over 200 worldwide deaths since 1988''. We have a brief article about [[Birdstrike simulator]]s too! [[User:SteveBaker|SteveBaker]] 17:31, 31 October 2007 (UTC)

Having a grating over the fan intake can introduce another problem. When engines are being tested, they have what they call a debris guard which fits over the front of the engine, but it means that the engine cannot be run in all conditions. To fully test the engine, at some point the guard needs to be removed.

This is because, at the speed the air enters the front of the engine, well over 300 miles an hour, it creates a huge cooling effect on the debris guard. That combined with the right (or wrong) level of humidity can cause ice to form on the guard. It has been known that enough ice has formed for the fan to create a vacuum behind the guard, and the result is, the entire guard is pulled through the engine, which will utterly destroy the engine, no question about that. On the other hand, with a bird strike, it's quite possible for an engine to keep running without any problems, especially if the bird is passed straight through the cold stream ducts and out the back. <small>—Preceding [[Wikipedia:Signatures|unsigned]] comment added by [[Special:Contributions/132.244.246.25|132.244.246.25]] ([[User talk:132.244.246.25|talk]]) 08:33, 1 November 2007 (UTC)</small><!-- Template:UnsignedIP --> <!--Autosigned by SineBot-->

== Taste bud abnormality ==

I was wondering if there is a name for the painful bumps that crop up on tongues from time to time. It seems as though a single taste bud turns white, enlarges, and becomes very sore to the touch. I can't seem to find a name for it anywhere (and no, it's not [[herpes simplex|herpes]] or [[Aphthous ulcer|canker sores]]) -- [[User:Macaddct1984|MacAddct1984]] 17:10, 30 October 2007 (UTC)

:Sorry, but this question is basically asking for a diagnosis, which we aren’t allowed to do here. As it says at the top of the page:

:'''Do not request regulated professional advice.''' If you want to ask advice that "offline" would only be given by a member of a licensed and regulated profession (medical, legal, veterinary, etc.), do not ask it here. Any such questions may be removed. See [[Wikipedia:Medical disclaimer]] and/or [[Wikipedia:Legal disclaimer]]. Ask a '''doctor''', dentist, veterinarian or lawyer instead. [[User:MrRedact|MrRedact]] 17:33, 30 October 2007 (UTC)

While MrRedact is correct that we can't diagnose, you might nevertheless be interested in the brief stub on [[lie bumps]]. It could stand to be filled out if you want to do some source research. --[[User:Trovatore|Trovatore]] 17:36, 30 October 2007 (UTC)
:Ah, thank you very much Trov! While I wasn't really looking for medical advice, I do realize there is a very fine line between "diagnosing" and what I was asking. But that is what I was looking for, I remember my mother always saying the old wife's tale was that you get them when you lie. -- [[User:Macaddct1984|MacAddct1984]] 17:53, 30 October 2007 (UTC)
::I can't say what this is in your case, but it also happens to me when I accidently scrape the area with a sharp piece of food or bite the tongue. Here's an article that discusses lie bumps a bit more: [http://www.womenshealthmag.com/article/0,6176,s1-3-70-584-1,00.html]. Again, this may not be what you have though. [[User_talk:Sanchom|Sancho]] 17:47, 30 October 2007 (UTC)

:they are basically caused by cuts in the tongue by food or your own teeth. If they are on the edge of a tongue it almost defiantly is caused by you biting your tongue accidentally. usually a mouth full of food pushes the tongue over the teeth and people bite without realising.--[[User:Dacium|Dacium]] 05:38, 31 October 2007 (UTC)

== how do i make my dog smart ==

please thank you <small>—Preceding [[Wikipedia:Signatures|unsigned]] comment added by [[Special:Contributions/77.234.83.173|77.234.83.173]] ([[User talk:77.234.83.173|talk]]) 17:19, 30 October 2007 (UTC)</small><!-- Template:UnsignedIP --> <!--Autosigned by SineBot-->
:See [[dog training]]. [[User_talk:Sanchom|Sancho]] 17:38, 30 October 2007 (UTC)

:I don't think you can change your dog's intelligence - as with humans, it's pretty much something that you're born with - but you can certainly enroll in a training course for you and your dog. Sadly, it generally turns out that your dog is plenty smart and it's you that gets trained - but that works too! We also have an article on [[Dog training]]. I have two dogs - one smart (female), the other dumber than a bag of hammers (male). The smart dog has learned to bark at the front door when she wants to be let in. The stupid dog has not. He just stares at the door hopefully. However, the smart dog has realised this and when she sees him standing there looking puzzled, she runs up to the door, barks until we open it and let him in - then she goes back to whatever she was doing before. [[User:SteveBaker|SteveBaker]] 17:43, 30 October 2007 (UTC)
::Intelligence can most certainly be changed in humans. And it's important that people are aware of that. There was a study recently that took two classes of high-school students, gave one a lecture about something boring and irrelevant (just to have a control), and gave the other a lecture on the nature of intelligence, and how intelligence and problem solving skills can be improved through training. After about half a year the second group showed a significant increase in grades and the first didn't. Of course there is always the criticism that training intelligence is just training for intelligence tests, but I believe strongly that intelligence by any reasonable definition can be consciously improved. I see no reason why dogs couldn't do the same, except that they probably won't have the mental capacity for defining the concept of intelligence, so they can't set it as a goal for themselves explicitly. Still, if you set out a wide range problem solving exercises with rewards that the dogs can understand (like the 'stack boxes to get to a banana'-kind of exercises they give monkeys, only simpler), they may generalize over all exercises and improve their problem solving intelligence instead of just learning specific tricks. [[User:Risk one|risk]] 18:16, 30 October 2007 (UTC)

thats a lot of reading, what's something simple ic an do like some toy i can buy or music to play. i cant afford obedience school. <small>—Preceding [[Wikipedia:Signatures|unsigned]] comment added by [[Special:Contributions/77.234.83.173|77.234.83.173]] ([[User talk:77.234.83.173|talk]]) 18:09, 30 October 2007 (UTC)</small><!-- Template:UnsignedIP --> <!--Autosigned by SineBot-->

:There are no magical shortcuts. If you can't afford obedience school - read our [[Dog training]] article carefully and do what it says - it's pretty much what the obedience schools teach. Set aside an hour a day for training. Make sure your dog knows that this is something special - "Now is training time - later will be play time" - so have a special routine you go through at the start and end so your dog will come to recognise that. [[User:SteveBaker|SteveBaker]] 00:08, 31 October 2007 (UTC)

::I have an instinctive negative reaction to the idea that learning to obey demonstrates ''intelligence''. I've always sort of felt that cats are smarter than dogs, precisely because they ''don't'' obey you. --[[User:Trovatore|Trovatore]] 01:33, 31 October 2007 (UTC)

:::Dog training is more about learning inter-species communication than obeying orders. I prefer to think of it as unlocking the intelligence that was always there - and in a way that we humans can understand. [[User:SteveBaker|SteveBaker]] 03:25, 31 October 2007 (UTC)

I don't know about smart but I made my dog smart''er'' with [[shock collar|this]] and [[choke chain|this]] and [[cookie|this]]. All three are essential. --[[User:DHeyward|DHeyward]] 05:40, 31 October 2007 (UTC)

:Get involved with [[Dog agility]] or [[Flyball]]. You and the dog have fun; you and the dog get to socialize; you and the dog get good outside exercise; and the dog's intelligence is developed. It's mostly just run by volunteers, so there's little cost.--[[User:Eriastrum|Eriastrum]] 17:06, 31 October 2007 (UTC)

== When you here about plane crashes on the news ==

They usually manage to find the Black Box flight recorder thing even in the worst crashes, when the rest of the plane has been completely destroyed by explosion and fire. So, why don't they make the planes out of the same material they make the black boxes out of? --[[User:84.68.112.172|84.68.112.172]] 17:50, 30 October 2007 (UTC)

: While black boxes are of durable construction, I think they benefit a great deal by being ''inside'' the aircraft. By analogy, I could get into a car wreck that's bad enough to total my car, but it's likely that my CD player would survive. It's not that it's made of some magic substance&mdash;it's just protected by the body of the car, which can deform and break up, absorbing a lot of impact energy. -- [[User:Coneslayer|Coneslayer]] 17:57, 30 October 2007 (UTC)

::In short, the black box is so heavily armored so as to survive the worst impact, that if the airplane was made similarly, it would be more like a tank than an airplane, and would be too heavy to fly. Planes are made to fly, CVR's are made to crash, as "they" say. :) [[User:Arakunem|<b>Arakunem</b>]][[User talk:Arakunem|<small><sup>Talk</sup></small>]] 18:03, 30 October 2007 (UTC)

:Check out this classic Cecil Adams column. [http://www.straightdope.com/classics/a4_001.html "If aircraft "black boxes" are indestructible, why can't the whole plane be made from the same material?"] [[User:69.95.50.15|69.95.50.15]] 18:01, 30 October 2007 (UTC)

:It's also worth noting that an indestructible airplane would provide little extra protection to all-too-destructible passengers, who are still independently subject to the laws of inertia. Crash casualties are not so much the product of a deforming airframe as they are of a sudden stop. In fact, the deformation is good -- it absorbs crash energy that would otherwise injure passengers even more. Modern cars are constructed with this same theory in mind. &mdash; [[User talk :Lomn|Lomn]] 18:12, 30 October 2007 (UTC)

:: I wonder if the querent is [[Black box (transportation)|looking for material]] for a stand up comedy routine? According to our article, [[Flight data recorder]]s tend to be "double wrapped, in strong corrosion-resistant stainless steel or titanium, with high-temperature insulation inside." We don't make jetliners out of titanium for the same reason we don't make windows out of diamonds, its not cost effective (though, as an aside, while the [[SR-71 Blackbird]] ''was'' made out of titanium, its windows were not diamond), and if we packed it full of high-temperature insulation, where we would put the passengers? [[User:Rockpocket|<font color="green">Rockpock</font>]]<font color="black">e</font>[[User_talk:Rockpocket|<font color="green">t</font>]] 18:14, 30 October 2007 (UTC)

:Also, black boxes aren't black - they're orange. [[User:SteveBaker|SteveBaker]] 00:04, 31 October 2007 (UTC)
::Depends on how hot the fire is. --[[User:DHeyward|DHeyward]] 05:09, 31 October 2007 (UTC)


:Even if the plane were made to survive a crash, it doesn't help people inside. Say the plane can survive 1000G of force, your body cant and you would be squished to death on impact, regardless of if the plane body deformed or didn't. The best solution for safety would have to be a plane that deforms enough so that a +100G impact is reduce to say 10G.--[[User:Dacium|Dacium]] 05:50, 31 October 2007 (UTC)

== Digitap imaging & printing ==

perfect on screen but when i printed it on my Epson stylus Photo RX620 it looked nothing like what it did on screen. I was truely gutted. It was duller, darker, more saturated & lost a lot of fine detail. I am using the correct paper & my ink channels settings are set to default. This is happening with all of my images.
Why is this happening & how can i resolve it so that what i create on screen prints as it looks on screen? Also what is the difference between a jpeg, tiff, Esp, btmap etc?

Thanks kindly

Nay <small>—Preceding [[Wikipedia:Signatures|unsigned]] comment added by [[Special:Contributions/86.145.223.206|86.145.223.206]] ([[User talk:86.145.223.206|talk]]) 19:33, 30 October 2007 (UTC)</small><!-- Template:UnsignedIP --> <!--Autosigned by SineBot-->
:For the latter, articles such as [[JPEG]], [[TIFF]], and [[BMP file format]] may be of use. For the former, I have no suggestion apart from experimenting with configuration settings (as this is not so much a case of correctness as one of preference). &mdash; [[User talk :Lomn|Lomn]] 20:05, 30 October 2007 (UTC)

:You may find this is better answered on the computing reference desk however I'll have a quick stab. Computer screens use additive colour. They add red, blue and green colours together to make white. Printers OTOH use ink which substracts colour. They use cyan, yellow and magenta and mixing them together makes black :-( So the screen will never look the same as a printer.

:Also ink jet printers use wet ink thqat runs a bit and the colours bleed together making it dull. Having a good quality laser printer and using top quality paper will definately produce crisper and brighter prints. Fortuately the cost of colours lasers has been plummeting in recent years [[User:Theresa knott|Theresa Knott]] | [[User talk:Theresa knott|The otter sank]] 20:10, 30 October 2007 (UTC)

:There are many problems here. Additive versus subtractive, impure inks and toners, the fact that you are printing in four colours (Cyan, Magenta, Yellow and Black) instead of three, that the printer needs to use dithering and bleeding of inks to do what it does, that the brightness of your screen is independent of the room lighting - but the brightness and hue of your print is entirely dependent on the colour of the ambient lighting - that the software that does the conversion is rarely correctly set up for the kind of paper you are using - that the gamma of cameras and screens are NEVER correctly set up, that not all programs take notice of the gamma values that the camera put into the file header - and if you save the picture out in another format, that information is almost certainly lost, that our eyes respond differently to a pigment that reflects yellow (meaning a true yellow) versus a seemingly identical pigment that reflects both red and green, that your CRT probably has several different colour temperature settings and you have no clue which one you picked...there are a million reasons. The bottom line is that you're doomed and you just have to tweak the available settings until you get it "how you like it". (There is no "Right"). [[User:SteveBaker|SteveBaker]] 23:50, 30 October 2007 (UTC)

:Oh - and the difference between various file formats (for the purposes of this discussion) are that JPEG and GIF both compromise the true colours of your photos in order to save a lot of memory. 24 bit TIFF and PNG can store colours in their original perfection with no losses whatever. BMP (urgh) can go either way - and it's a horrid format anyway so don't use it. The various 'raw' formats that cameras sometimes use are better still - IF you have the right software to handle them. There are some esoteric formats that do even better - but I doubt you'll ever come across them. On balance:
:* Use PNG for original artwork and photos stored on your computer at home - where (presumably) you have plenty of disk space.
:* Use RAW images for original photo archives if your camera and software supports them - but convert to PNG for day-to-day use.
:* Use JPEG for photographic types of pictures on the Internet - it's compact - which means it downloads quickly - and the losses due to it's compression tricks are not noticable on a typical browser at the default screen resolutions we have these days. As broadband starts to conquer the world - I'm going more and more towards using PNG even in these situations.
:* Use GIF '''only''' on really high usage web pages for cartoony stuff or (if you absolutely must) for animated images.
:* Don't use TIFF or BMP if you can possibly avoid it - they are both only patchily supported in areas like gamma that truly matter.
: [[User:SteveBaker|SteveBaker]] 00:01, 31 October 2007 (UTC)

== Mom Haircut ==

Okay, this is a stretch, but I'm going to try it anyways... just bear with me, okay?

Is there a condition or an illness (for lack of a better word, I don't mean to imply bad health) that would describe the tendency for new mothers to get a drastic haircut? I don't mean the "mom haircut" but, just even like dying it a different color, something that makes a dramatic change. I know this could just be associated with going through major changes in their life or, more dangerously, depression, but I was wondering if there was a name for it specifically. Thanks, and I apologize if this question is just too dumb for words.
[[User:Beekone|Beekone]] 20:18, 30 October 2007 (UTC)
:You might find more information under the [[mid-life crisis]] article -- [[User:Macaddct1984|MacAddct1984]] 20:43, 30 October 2007 (UTC)

: One could argue it is an evolutionary successful strategy: long hair is an energy intensive characteristic adopted by females to attract a mate. After pair bonding and generating offspring, the female no longer considers the energy invested in maintaining long hair is no longer required, hence they cut it. Or it could be that they don't want to get [[Louse|nits]] from all the little brats they interact with. Or it could be to reinvent themselves for the next stage in their lives, or it could be part of an effort to "look good" again after the physical changes associated with child birth. Interestingly (or not) there [http://www.parentdish.com/2006/07/26/do-you-have-mom-hair/ does seem] to be some recognition of "mom hair" in the mommy blogosphere, but its extremely unlikely that it has a specific biomedical name. [[User:Rockpocket|<font color="green">Rockpock</font>]]<font color="black">e</font>[[User_talk:Rockpocket|<font color="green">t</font>]] 20:45, 30 October 2007 (UTC)

:I'm not even sure what you are describibg is a real phenomenom. Is there any data to suggest that on average new mums get more dreastic haircuts than women of that age who are not new mums? [[User:Theresa knott|Theresa Knott]] | [[User talk:Theresa knott|The otter sank]] 20:52, 30 October 2007 (UTC)

::No, I'm not sure such research exists... I guess that's why I asked. It seemed like a funny quirk that I'd noticed in some friends and acquaintances. I agree that the likelihood of this activity having a specific medical name is extremely un, but you never know until you ask, right? [[User:Beekone|Beekone]] 21:05, 30 October 2007 (UTC)

::Googling "mom haircut" at least provides evidence that the "mom haircut" is culturally believed to be a real phenomenon. From reading the various pages, it sounds like a "mom haircut" is either quite short, or long and tied back. In either case, it sounds like the point is to have a low-maintenance, no-nonsense haircut that isn’t going to get in the way of the harried new mother, who suddenly has less time for dealing with such frivolities as hair. [[User:MrRedact|MrRedact]] 21:30, 30 October 2007 (UTC)

:::Don't think anyone has mentioned the obvious answer (well, obvious to anyone with practical experience of babies), which is that babies of a few weeks and older love to practise their hand-eye co-ordination by grabbing and pulling long hair. [[User:Gandalf61|Gandalf61]] 10:39, 31 October 2007 (UTC)

"I don't mean the "mom haircut" but, just even like dying it a different color, something that makes a dramatic change. " signed, the very first post!
Read, think, reread, comprehend... maybe [[User:Beekone|Beekone]] 13:04, 31 October 2007 (UTC)

:You start off with: "Is there a condition or an illness ... that would describe the tendency for new mothers to get a drastic haircut?" If you are going to ask contradictory questions, you are going to get contradictory answers. [[User:Rockpocket|<font color="green">Rockpock</font>]]<font color="black">e</font>[[User_talk:Rockpocket|<font color="green">t</font>]] 17:14, 31 October 2007 (UTC)

:: How does "drastic haircut" translate into "mom haircut"? I mean I know I called the topic that, but I state repeatedly that that's not what it's about. To be technical I start off with this: "Okay, this is a stretch, but I'm going to try it anyways... ''just bear with me, okay?'' " 'Clearly the message is going to be muddled so I should pay close attention,' thought the reader. [[User:Beekone|Beekone]] 17:18, 31 October 2007 (UTC)

:: Additionally, I liked your answer, Rockpocket. You seem to get what I was asking, and correctly stated that such a condition is unlikely to have an actual label. But at least you got what I was asking, even if you're answer was basically "I don't know." The other answers are "I don't know" plus a hint of "I obviously didn't try to get what you were asking" which i frustrating because if you don't know why even answer? Just pass it by. I obviously asked in the case that someone with knowledge of the topic might answer. It's sort of what the Help Desk is all about... in my understanding anyways. [[User:Beekone|Beekone]] 17:23, 31 October 2007 (UTC)
::: Thats a fair point, well taken. [[User:Rockpocket|<font color="green">Rockpock</font>]]<font color="black">e</font>[[User_talk:Rockpocket|<font color="green">t</font>]] 04:10, 2 November 2007 (UTC)

== Why don't they use water jets on very large ships? ==

The largest they used it on was a frigget I think. Why not larger ships? [[User:64.236.121.129|64.236.121.129]] 20:26, 30 October 2007 (UTC)
:Our article on [[pump-jet]]s notes some of their advantages, contrasted with a decrease in efficiency versus propellor-based designs. In particular, the note about power density may be relevant, as [[Frigate#Modern_frigates|frigates]] don't have as much hull volume to fill with engines as do [[destroyer]]s or [[cruiser]]s. The shallow-draft advantages provide additional merit for new [[littoral combat ship]]s. At some level, though, the lack of adoption may simply be industrial inertia. Propellors are well-understood and consequently are considered to inherit less risk than a relatively new technology like pump-jets. In the absence of a compelling advantage for the latter, then, the former is likely to remain in widespread use. &mdash; [[User talk :Lomn|Lomn]] 20:36, 30 October 2007 (UTC)
:Many very large ships still have bow thruster jets.--[[User:Dacium|Dacium]] 23:54, 30 October 2007 (UTC)

== Sugar in Soda ==

I've decided to eliminate [[soda]] from my diet. While shopping at a local grocery store, I came across a powder lemonade product that one mixes with water. The lemonade’s packaging said it "contained 40% less sugar than soda." So with everything being equal between the soda and the lemonade (calories, fat, etc), what would be the benefits of 40% less sugar? I would assume that there would be some benefits…or is this a fancy marketing ploy?

Thanks [[User:64.85.199.27|64.85.199.27]] 20:41, 30 October 2007 (UTC)

:It's precisely a marketing ploy. Whether it actually benefits you depends entirely on your diet. People hear that carbs are bad, carbs make you fat, so they advertise that they have fewer carbs. Sugars/carbs are the normal person's primary source of energy, and it is the first form of energy (calories) the body will burn in order to operate (fats it prefers to store away). Now, if the food in your diet contains all the calories you need in a day, and you just want something to quench your thirst, there's really no need to drink something laced with sugar that will just get converted into fat for long term storage, so you may as well go for that low-sugar lemonade. [[User:Someguy1221|Someguy1221]] 20:47, 30 October 2007 (UTC)

:(ec)Soda contains a ''lot'' of sugar! 40% less means 60% still remaining which is still very bad for your teeth. Having said that soda contains not fat, protein etc. It's water and sugar, so 40% less sugar will be 40% less calories. Those calories that remain are junk food calories though. Much better to drink water or tea. [[User:Theresa knott|Theresa Knott]] | [[User talk:Theresa knott|The otter sank]] 20:49, 30 October 2007 (UTC)

:Also, the drink may have had that 60% of sugar boosted by an artificial sweetener, and if you read [[sugar substitute]] you'll see that all the common ones have some kind of controversy about potential health risks attached. [[User:ConMan|Confusing Manifestation]] 21:39, 30 October 2007 (UTC)

:Just drink diet or zero soda's (diet coke, coke zero, pepsi max etc). These contain zero suger. Also other things that are high in suger are sauces like ketchup, alcohol etc. Personally I would try to ditch soda all together and drink water. Try drinking two classes of water before you eat.--[[User:Dacium|Dacium]] 23:27, 30 October 2007 (UTC)


:There are two very different things being talked about here. Diet Coke/Pepsi/whatever contains almost zero carbs. Giving up Diet coke and drinking this stuff will increase your carbs by a large percentage because their claim to have less carbs than "Soda" is a poorly worded and highly misleading statement. WHICH soda do they have 40% less than? If has 40% less than one of those insane "energy drinks" ([[Mountain Dew MDX]] for example) then it probably has more sugar than Classic Coke too! Different kinds of soda have everything from zero sugar up to (probably) the maximum amount that'll stay dissolved in water without crystalizing out! It's nothing to do with whether it's carbonated or not. So if you need to reduce your sugar intake, switch to a diet soda. If you are concerned about the CO2 in the soda - then switch to a non-carbonated beverage. But don't give up either "just because". Read the ingredient list and compare the actual numbers - forget the silly marketting percentages. Think about what you are really doing! As others have mentioned, if you get your total carbohydrate intake down to zero - you'll get seriously ill amazingly quickly of something called "protein poisoning" (aka [[Rabbit starvation]]). [[User:SteveBaker|SteveBaker]] 23:39, 30 October 2007 (UTC)
:Actually sugar will dissove in huge amounts in water without crystalising out. I suppose the max would be something like [[golden syrup]] but you would't drink that. [[User:Theresa knott|Theresa Knott]] | [[User talk:Theresa knott|The otter sank]] 00:35, 31 October 2007 (UTC)

== Will it fly? ==

[[Image:Willitakeoff.jpg]]

I say yes, and so does [http://www.straightdope.com/columns/060203.html straightdope], but what is the answer????--[[User:Goon Noot|Goon Noot]] 23:08, 30 October 2007 (UTC)

:Yes it will. Airplanes move due to thrust from the engines, not torque from the wheels. The plane's wheels will just be spinning at 2x the takeoff speed when it leaves the ground. [[User:Arakunem|<b>Arakunem</b>]][[User talk:Arakunem|<small><sup>Talk</sup></small>]] 23:11, 30 October 2007 (UTC)



I say nay. There is no lift because the plane isn't moving forward.
:It is moving, but it is on the treadmill, and the treadmill isn't moving forward.

strap that whole shebang on top of a car... then we're talking <small>—Preceding [[Wikipedia:Signatures|unsigned]] comment added by [[Special:Contributions/128.175.187.238|128.175.187.238]] ([[User talk:128.175.187.238|talk]]) 05:59, 31 October 2007 (UTC)</small><!-- Template:UnsignedIP --> <!--Autosigned by SineBot-->

-Stephen Hawking <small>—Preceding [[Wikipedia:Signatures|unsigned]] comment added by [[Special:Contributions/74.196.103.230|74.196.103.230]] ([[User talk:74.196.103.230|talk]]) 23:15, 30 October 2007 (UTC)</small><!-- Template:UnsignedIP --> <!--Autosigned by SineBot-->

::It's an enormous treadmill, but the aeroplane's wings will be ripped off as it starts to fly. [[User:DuncanHill|DuncanHill]] 23:17, 30 October 2007 (UTC)

: In the original formulation of the question, the treadmill was infinitely long and the wheels completely free-running. The photo just confuses the question. The plane doesn't give a damn what happens to its wheels - they are free-running. Moreover, once it's engines are running with enough power to overcome the tiny amount of rolling friction in the wheels, the plane will take the same distance to take off no matter what speed the treadmill is running (forwards, backwards, who cares?). This one has been done-to-death and the answer is as clear and obvious now as it was at the beginning. I don't believe Stephen Hawking (or at least "The" Stephen Hawkin) said that. [[User:SteveBaker|SteveBaker]] 23:21, 30 October 2007 (UTC)


: It 100% will not take off. There is no way for it go gain lift. The plan engines thrust forth, pulling the wing, with the idea that the wing is pulled fast through the air, air goes over the wing and creates lift. There is no way for the plain to gain lift. People who think it could take off must also believe that a plane with no wheels could simply turn on its engines and hover up in the air.--[[User:Dacium|Dacium]] 23:22, 30 October 2007 (UTC)

::If you think about it, any plane is already on a giant moving treadmill. It's called the Earth. Remember that all motion is relative, so putting a plane on a treadmill moving with constant velocity is really no different from having a wind coming up from behind the plane. From the plane's perspective, it has to go a little faster to take off because of this wind. From your perspective, it takes off at normal speed, but it takes a little longer to reach it (since it started moving backwards with the treadmill) and the wheels will be turning faster. Now, you could also have the treadmill ''accelerating'' backwards at the same rate the airplane accelerates while taking off. In this case, the plane sits where it is, the wheels constantly speeding up, and the engines working to keep the plane exactly where it is (although, in that case, you could just turn the plane around and use the treadmill to launch it). '''Simply put''', all motion is relative, being a treadmill won't have any greater effect on the plane than wind. [[User:Someguy1221|Someguy1221]] 23:24, 30 October 2007 (UTC)
:::A plane moves forward by air entering the engines to create thrust. A plane has to build up it speed because there is only little thrust to begin with. As the plane gets faster, more air is entering the engine and the thrust increases. It is the air speed relative to the plane that is the only thing that matters. A plane could hover straight up in the air if the air speed was great enough. The treadmill stops the plane gaining speed relative to the air and stops it taking off.--[[User:Dacium|Dacium]] 23:44, 30 October 2007 (UTC)

::::The plane still ''moves''. Unless the treadmill is accelerating, the plane will eventually beat it and take off. Imagine the treadmill is massive, say, the ''Earth''. Would the plane notice or care if the treadmill were moving? Not unless it's accelerating. So this is why I say, if the treadmill is moving backwards at 30mph, this is no different than a tailwind of 30mph. The plane has to speed up a little more (from its own perspective) to generate sufficient lift. But it is by no means prevented from moving. [[User:Someguy1221|Someguy1221]] 23:49, 30 October 2007 (UTC)

::::Sorry I thought we were assuming the treadmill was accelerating to match the speed of the plain. Obviously if it doesn't the plain will still be able to gain speed relative to the air, and take off. So we are all in agreement then. Non accelerating treadmill - plain takes off. Accelerating treadmill - plane does not take off.--[[User:Dacium|Dacium]] 23:52, 30 October 2007 (UTC)
::::: The treadmill would have to have '''tremendous''' acceleration to slow the plane below its takeoff speed. (Remember, the wheels are free-wheeling. The only thing slowing the plane is double the normal amount of friction in the axles. The situation is nearly the same as if the plane had hovercraft instead of wheels. ) I'm pretty sure that a treadmill constructed to put out that sort of ridiculous acceleration would reach near-C speeds in a minute or two then the plane could still take off normally. [[User:69.95.50.15|69.95.50.15]] 18:42, 31 October 2007 (UTC)
:::::So I have this funny feeling I may have my relativity backwards on the accelerating part, someone please check me on that. [[User:Someguy1221|Someguy1221]] 23:57, 30 October 2007 (UTC)
:::The wheels play zero part in generating forward speed. The engines react against the air to generate forward thrust. The treadmill could be going faster in "reverse" than the plane is moving forwards, and it will still move forward. The wheels would be spinning reeealy fast backwards but thats irrelevant to this. [[User:Arakunem|<b>Arakunem</b>]][[User talk:Arakunem|<small><sup>Talk</sup></small>]] 23:33, 30 October 2007 (UTC)

:It all depends on how you define the question. If the airplane's wheel bearings are frictionless and the wheels themselves are inertialess, then it doesn't matter what the treadmill does: the airplane's engines will move the airplane forward and it will take off. If the wheels have rotational inertia, or the wheel bearings have friction, and the treadmill is allowed to adjust its speed without limit, then it is possible to use the friction or rotational inertia of the wheels to counter the thrust of the engines, and the airplane won't take off. --[[User:Carnildo|Carnildo]] 00:03, 31 October 2007 (UTC)

::I think it's best to assume the plane is just a normal plane, with normal wheels. [[User:Someguy1221|Someguy1221]] 00:08, 31 October 2007 (UTC)
:::Say a big plane like in the picture takes off at about 150mph, do you think it could take off with a 150mph tail wind? I don't think so. So imagine the treadmill is already travelling with the plane on it at 150mph backwards, can the plane take off? I don't think so. Now imagine the plane and the treadmill both start at 0mph, can the treadmill accelerate the plane backwards as fast as the plane accelerates forwards? I don't think so. At the very start of the plane's acceleration as the engines spool up a considerable amount of the thrust would be used to overcome the friction in the wheels, but very quickly as the thrust increases, I think the treadmill would have to travel MUCH MUCH faster backwards then the plane accelerates forward for the friction of the wheels to act as a break on the plane's forward acceleration, otherwise the plane will come to speed and take off, just with very fast spinning wheels. [[User:Vespine|Vespine]] 00:54, 31 October 2007 (UTC)

::Yes, if the treadmill is allowed to transfer enough net force through friction in the wheels it could hypothetically keep the plane stationary. If the plane is stationary with respect to the air, it will not take off, since lift depends only on the plane's speed with respect to the air. [[User:Dragons flight|Dragons flight]] 00:57, 31 October 2007 (UTC)

:::Just to straighten things out hopefully. Assume still air (no headwind or tailwind). If the conveyor belt/plane contraption is set up so that the plane remains motionless relative to the air (whether or not the conveyor belt, wheels, or engines are going) the plane will not take off as no air is moving over the wing generating no lift. If the plane is moving forward relative to the air, it could take off. Another way to think about this problem is to envision a plane on a conveyor belt that pushes the plane forward while the plane's engines are off and the wheels not rolling at all. Will the plane take off? Yes, because air is moving past the wings generating lift. (Of course to maintain flight it needs the engines, but that is besides the point) Or you can envision it this way: with a strong enough headwind, a plane perfectly at rest could take off although to a stationary observer on the ground, the plane would be moving backwards while acquiring altitude (i.e. moving in the direction of the wind). I hope this helps. [[User:Sifaka|<font color="Green">'''Sifaka'''</font>]] <sup>[[User talk:Sifaka|'''<font color="Green">talk</font>''']]</sup> 03:59, 31 October 2007 (UTC)

:No, it will hit the handrails of the treadmill. (Darn, DuncanHill beat me to that answer :P)-- [[User:Diletante|Diletante]] 01:10, 31 October 2007 (UTC)

It's worth noting (belatedly) that we did this question to death back on [[Wikipedia:Reference desk/Archives/Science/2007 May 21#Plane on treadmill|May 21]]. —[[User:Ummit|Steve Summit]] ([[User talk:Ummit|talk]]) 01:31, 31 October 2007 (UTC)

:: More importantly, would a bird flying in front of the treadmill get sucked into the plane's engine? [[User:Rockpocket|<font color="green">Rockpock</font>]]<font color="black">e</font>[[User_talk:Rockpocket|<font color="green">t</font>]] 01:39, 31 October 2007 (UTC)
:::Yes because the engines are drawing in air. [[User:71.226.56.79|71.226.56.79]] 04:02, 31 October 2007 (UTC)

:If the treadmill matches whatever the speed the plane can do, then surely it would stir up a huge surface headwind wouldn't it? Voilà, there's your moving air. --[[User: Antilived|antilived]]<sup>[[User_talk:Antilived|T]] | [[Special:Contributions/Antilived|C]] | [[User:Antilived/Gallery|G]]</sup> 07:09, 31 October 2007 (UTC)

::A treadmill moving at 100 or 150 mph wouldn't stir up that much of a headwind. ([[Airplane!|And stop calling me Shirley.]]) —[[User:Ummit|Steve Summit]] ([[User talk:Ummit|talk]]) 12:01, 31 October 2007 (UTC)

:::It doesn't have to limited to 100 or 150mph. Assuming it's a perfect treadmill it and the plane will simply accelerate until there's enough induced wind from the treadmill for the plane to take off. --[[User: Antilived|antilived]]<sup>[[User_talk:Antilived|T]] | [[Special:Contributions/Antilived|C]] | [[User:Antilived/Gallery|G]]</sup> 05:13, 1 November 2007 (UTC)

It won't take off because there's no airflow around the wings! That's the whole point of why you need a runway for an airplane. You could say the Earth is a giant treadmill, but the air moves with the earth, and so do we. Air does not move with the treadmill. I'm surprised some of the people here thinks it will take off. It really makes me doubt how credible they were to answer my question about the ducted fans aircraft. Maybe it will take off if you have a powerful fan in front of the plane, but then you don't need a treadmill in the first place. Just thrust against the wind. [[User:64.236.121.129|64.236.121.129]] 13:23, 31 October 2007 (UTC)
:::Aww you're mad *pats your head. You're also thinking of it wrong. I'm not going to bother explaining it because your last few posts prove that you aren't interested in listening. *pats your head*. Just because you don't understand it, doesnt mean it isnt so. Now you run on back to Starcraft lil guy <small>—Preceding [[Wikipedia:Signatures|unsigned]] comment added by [[Special:Contributions/207.67.148.212|207.67.148.212]] ([[User talk:207.67.148.212|talk]]) 15:49, 31 October 2007 (UTC)</small><!-- Template:UnsignedIP --> <!--Autosigned by SineBot-->
::::As I thought I made clear in my Earth/treadmill analogy, the only point of that is to dispel any belief that frame of reference is important. The only difference the plane cares about is the relative wind speed. [[User:Someguy1221|Someguy1221]] 17:11, 31 October 2007 (UTC)
::Actually, this is quite backwards. It takes off fine from a treadmill under the generally stated conditions (the treadmill moves at the same speed as the aircraft). Carnildo raises a good point that wheels aren't frictionless, and if you allow the treadmill to run so fast that the airplane is stationary, then it won't lift off (probably -- you're left with a weird feedback cycle). Thus, the key point of properly stating your constraints and assumptions is illustrated. On the other hand, a stationary aircraft in front of a fan can lift off, but as soon as it's no longer in front of the fan, it crashes due to the rapid change in airspeed over the wings (as opposed to the treadmill liftoff, in which the aircraft flies away normally).


'''In a related question''', A friend once suggested to me that the real issue in this situation would be that the wheels would be turning at double their normal RPM (obviously). He suggested that the tires on many jets are not rated for those RPMs and would destroy themselves before the plane went airborne. Is this true? Stated more clearly, if a 747 was placed on a treadmill like the one described so that its wheels were always turning at double the normally expected rate, would the plane survive takeoff? [[User:69.95.50.15|69.95.50.15]] 18:36, 31 October 2007 (UTC)
:With no true evidence, I'll say "probably". The wheels undergo significantly more stress at landing (going from no speed to 150 MPH or so very quickly) and have a sizeable engineering margin above that. Simply spinning on takeoff should be no big deal. &mdash; [[User talk :Lomn|Lomn]] 19:13, 31 October 2007 (UTC)
: For the consequences of a tyre failure on takeoff, see [[Air France Flight 4590]]. Admittedly, the tyre failed due to debris on the runway, but airplane tyres were subsequently redesigned. -[[User:Arch dude|Arch dude]] 22:25, 31 October 2007 (UTC)
:::As i stated in my post, the "initial" resistance of the wheel would be very quickly overcome by the acceleration of the jet engine and I belive the wheels would have to spin MUCH MUCH more then twice as fast. Think of this, scale down the plane so it fits on a piece of paper on a desk, move the paper slowly and the plane will move with it, move the paper fast and the plane won't move, the wheels will just spin faster, i think the same thing will happen with a jet. Once the engines are at full thrust i think moving the treadmill backwards WON'T be able to stop the plane from accelerating, it will just make the wheels spin faster backwards, unless you start spinning then SO fast as to act as a break, in which case I think probably eventually fast enough to fail. [[User:Vespine|Vespine]] 06:04, 1 November 2007 (UTC)
::::I was referring to the most commonly stated version of this problem where the treadmill goes backwards at the plane's take-off speed. In this case the plane takes off almost normally except for the tires which spin double their normal speed. [[User:69.95.50.15|69.95.50.15]] 16:32, 1 November 2007 (UTC)

I think the main point here is that the air will not move with the treadmill. People seem to be thinking here that somehow either the treadmill can move the air, or the plane's engines drive the wheels. Either way you need air movement over the wings to generate lift. The treadmill's movement, forward, backward, whatever has no bearing on the air. The plane still needs to be pulled (by its engines) through the air forward to generate lift. The force from the engines act on the air, not the ground, so how the ground is moving has no bearing. The plane in that picture absolutely would not leave the ground. It's like having someone holding a hang-glider and running on a treadmill. They're not going to suddenly zoom up into the air, because the wing isn't travelling through the air. That's the whole point of a treadmill, so you don't move anywhere. <small>—Preceding [[Wikipedia:Signatures|unsigned]] comment added by [[Special:Contributions/132.244.246.25|132.244.246.25]] ([[User talk:132.244.246.25|talk]]) 08:45, 1 November 2007 (UTC)</small><!-- Template:UnsignedIP --> <!--Autosigned by SineBot-->

Hey, let's put this a couple of different ways:
*You've got a 3 km runway, well and truly long enough for about any plane. But some tricky person has replaced the surface with a conveyor belt loop. The belt runs at 100km/h (~60mph). Can a Cessna 152 take off?
Plane is dropped onto the runway at the North end, facing north, and starts accelerating south (backwards). The engine's running and is throttled up to maximum, it starts moving forwards, engine slowed so it progresses backwards at walking pace (5km/h), that's groundspeed (relative to treadmill) +95km/h, airspeed -5km/h, groundspeed relative to control tower -5km/h. The Cessna gets half way down the runway, pilot decides to stop stuffing around, and throttles up to max, speed increases, at 120km/h airspeed it takes off, that's airspeed=120km/h, groundspeed relative to tower=120km/h (it's using up runway at 120km/h and getting rapidly closer towards the end), groundspeed relative to treadmill = 220km/h - well within design limits of the plane. Yep. It flies.

Of course, you can make the situation work or not work as you please by tweaking the setup. Sure you can find a treadmill speed where the plane's wheels are wrecked, sure you can make the plane too large or the treadmill runway too short for the plane to take off - but was that the question?

If the original question was "We have a cessna 152, with a flying speed of 120km/h, on a treadmill as long as the plane. The treadmill is run up to 120km/h, will the plane fly?" the answer to that is an emphatic "no", groundspeed is irrelevant to whether a plane flies. --[[User:Psud|Psud]] 10:00, 1 November 2007 (UTC)
: You mean an emphatic "yes", right? Because the Cessna will have the same airspeed it always has. It's 'groundspeed' would be double if you're counting the treadmill as the ground, but like you said, the groundspeed is irrelevant. (The wheels are free-spinning, Imagine them as hovercraft if that helps you.) [[User:69.95.50.15|69.95.50.15]] 16:38, 1 November 2007 (UTC)

Relative to the surrounding air this plane is motionless. Ergo the lift = 0. Ergo it won´t take off.<br />The tradmill is totally irrelevant.<br />--[[User:Cookatoo.ergo.ZooM|Cookatoo.ergo.ZooM]] 23:12, 1 November 2007 (UTC)

::PS: It is identical to a normal plane on a "normal" runway taking off at a tailwind which inceases parallel to the speed of the accelerating plane. The Cessna / Jumbo / whatever could travel at the speed of Mach x or even v=c. As long as the velocity of the tail wind is identical, there are no aerodynamics to create a counter-gravitational force.<br />QED. --[[User:Cookatoo.ergo.ZooM|Cookatoo.ergo.ZooM]] 23:27, 1 November 2007 (UTC)
:ZOMG, people are still not getting it.... but the plane is accelerating with JET THRUST not with the wheels, the plane, at full throttle, WILL accelerate through the air, regardless whether the wheels are spinning forward or backwards, the ground and wheel resistance is negligible to the thrust of the engines. there is a clip on youtube of a thrust test where a bus behind a jumbo jet, not RIGHT behind either, some way behind, is blown clean over and away by the blast from the engines. Put it this way, people agreed that the treadmill will NOT be able to move a significant amount of air with it, right? So it MUST also work in reverse, is the treadmill, even going super fast enough to counteract ONE HUNDRED THOUSAND LBF of thrust?? NO WAY! The plane WILL accelerate and WILL take off. Actually using that example, I've changed my mind from my previous post, I think it will accelerate and take off even if it starts at "going backwards" on the treadmill at whatever speed, it will just take longer for it to gather the airspeed... the people who think it will not take off are essentially making the assumption that a treadmill under the plane can counteract the acceleration of 100000 lbf of thrusting air, no way no how. [[User:Vespine|Vespine]] 00:51, 2 November 2007 (UTC)

It's becoming clear that this is, in effect, a troll question. It is specifically designed to fuck with your head. The more you think about it, the more confused you get. Or, even if you don't overtly confuse yourself, you find yourself compelled to come up with ever-more bizarre theories to explain how the plane might ''not'' be able to take off.

And if you stop and ''really'' think about it, coming up with those ever-more bizarre theories is a pretty stupid thing to do. Remember, the primary purpose of the question is to fuck with your head and spark meaningless but prolonged debate. When the people who aren't thinking clearly say "Oh, right, of course the plane won't take off", the sadistic person who thought up the question in the first place calls them stupid and has a good laugh at their expense. But seriously: you think he's ''not'' also laughing at you when you get all "clever" and come up with some exotic and barely-plausible (well, even less plausible than a runway-sized treadmill, that is) theory under which you get ''exactly the same answer as the stupid people!?''

As we all hopefully know by now, the proper response to trolls is to ignore them, to not feed them, to wait patiently for them to get bored and go away. And I think we had best apply the same remedy to this dorky airplane-on-a-treadmill question, too. (And soon, before this thread achieves critical mass and collapses into a black hole, or something...) —[[User:Ummit|Steve Summit]] ([[User talk:Ummit|talk]]) 04:57, 2 November 2007 (UTC)

Oops. I recant my above statements. The devil made me do it!<br />Due to a brief attack of fallibilty, causing delusions of omnisciensce, I uttered what may be classified as pure and unadulerated bovine faeces.<br />Thank God I am not a pope or president, but just a humble wheel on a treadmill, attempting to soar into the heavens of perpetual knowledge and eternal bliss...<br />I promise to take my prescibed medicine in future !--[[User:Cookatoo.ergo.ZooM|Cookatoo.ergo.ZooM]] 13:00, 2 November 2007 (UTC)

= October 31 =

== Running hands under Superacid ==

After reading [[Superacids]], what would happen if someone washed their hands under a tap of fluoroantimonic acid? How fast would the hands disintegrate? [[User:Acceptable|Acceptable]] 01:35, 31 October 2007 (UTC)
:I guess it is unacceptable to post chromic acid stories? [[User:Delmlsfan|Delmlsfan]] 01:51, 31 October 2007 (UTC)

::I once breathed in fumes of [[hydrogen chloride]] gas (by accident), not a very fun experience... -- [[User:Macaddct1984|MacAddct1984]] 14:02, 31 October 2007 (UTC)

:Once it hits the water of your hand, it's no longer nearly as super. That is, it becomes little different than a really really concentrated solution of other acids (hydrochloric, sulfuric, etc) in regards to its acid effects. On the other hand (sorry:) the fluoro and stibbic components might present other hazards all their own. [[User:DMacks|DMacks]] 02:01, 31 October 2007 (UTC)

== Transporting rice ==
[[Car Talk]]'s most recent puzzler was something along the lines of:
:::With old wooden ships, what common household item, if not stored properly, would sink a ship in a matter of minutes?
Apparently rice was the answer. If it wasn't stored properly and got wet, the massive amounts of densely packed rice would swell and split the ship apart. Has anyone heard of this before? It certainly sounds plausible. -- [[User:Macaddct1984|MacAddct1984]] 01:42, 31 October 2007 (UTC)

:Car Talk got this information from the book Tall Ships by Philip McCutchan.[http://www.cartalk.com/content/puzzler/transcripts/200742/answer.html] The author’s name is misspelled on Car Talk’s web site.[http://www.amazon.com/gp/offer-listing/B000O5HFM2/ref=dp_olp_2/103-8941892-0853442?ie=UTF8&qid=1193799131&sr=8-38] That book says "Spaced along the upper deck were the cargo hatches with their heavy covers of reinforced hardwood planks, well chocked in and secured with three separate layers of tarpaulin, held down with ropes and more chocks to withstand the pounding of heavy seas. Below the hatches lay the reason for the ship's presence on the sea, her cargo, to be held inviolate against nature and disaster, against fire that could come from a self-combustible cargo like wool, or a cargo that could swell when it met water, such as rice, which on more than one occasion in the long story of the sea swelled and in its irresistible pressure split the sides of holds like paper and sank those ships in minutes."

:But that’s just what Philip McCutchan said. From the British shipping act in 1875, it sounds like the primary concern about properly storing grain on ships at the time was actually that the ship could sink if the grain shifted.[http://reallypuzzled.com/2007/10/22/demystifying-a-puzzler-the-cargo/] Maybe this is a question for [[MythBusters]]. [[User:MrRedact|MrRedact]] 03:25, 31 October 2007 (UTC)

:I guess what bothers me about this is that once the water gets at the outer regions of the rice cargo, that will start to swell and the pressure build-up ought to lock out the water from getting in much further. But a lot depends on how fast the water is getting in and how fast rice swells. I guess it could be true. Definitely a good one for Mythbusters though. Car Talk's puzzlers are not exactly reliable sources of information! [[User:SteveBaker|SteveBaker]] 03:32, 31 October 2007 (UTC)

::This was a plot in a [[Horatio Hornblower]] book. He lost a prize of war. The ship was sinking even though no water was in the "well". It gains weight as well as stressing the hull. --[[User:DHeyward|DHeyward]] 05:18, 31 October 2007 (UTC)

::For the locking question, I think osmotic pressure will keep sucking the water in to the center until they are all equally saturated. A dry rice grain next to water saturated one will suck the water out of it. --[[User:DHeyward|DHeyward]] 05:21, 31 October 2007 (UTC)
:::[[User:DHeyward|DHeyward]]: that was not a book, but rather the second chapter of [[Mr. Midshipman Hornblower]]. [[User:Algebraist|Algebraist]] 21:08, 31 October 2007 (UTC)

== Children's vs Adult's voices ==

* What are the differences between children's and adult's voices, excepting the obvious physiological effects of growth and hormonal adjustments?
* For example, children's voices tend to sound more sing-songy, breathy, and rhymical, but have there been any studies to make quantitative or qualitative measures of the difference in voice-qualities as age progresses?
* It is obvious that human's are readily able to differentiate between younger and older speakers independently of any use of linguistic cues : are computers able to do the same, and under what heuristics would they operate?
* Are there any posited hypotheses of the cognitive causes of these non-physiologically determined variations?
Many thanks [[User:81.153.3.36|81.153.3.36]] 10:05, 31 October 2007 (UTC)

:I think this belongs in the section on Language and Linguistics. Meanwhile, I'm not well studied at all in developmental linguistics, but I can try to answer with what I know.

:Obviously, as you stated, as a child gets older his larynx expands and produces deeper tones as the vocal chords vibrate. Similar resonance differences occur as the size of the oral and nasal cavity expand. However, the prosodic changes (those in rhythm and tone) can probably be traced to what are still not well understood phenomena in child linguistics. For example, a toddler will show reduplication (repetition of words) and other types of word play, depending on age, as he learns to speak. He will also exaggerate and misuse intonation (the parents do this too when they speak to children for the precise reason that intonation is ''difficult'' to master). All of this is most likely a result of the problem of learning something as complicated as language simply from cues around you. Computational models of this type of learning are very simplistic, last I've seen, and usually involve limited degrees of freedom (such as a simple robot learning to walk or play the drums according to outside information). None that I know of are linguistic in nature.

:It is true that the age of a speaker can be approximated by linguistic cues alone. This is done in precisely the same manner as you mentioned, as well as by judging vocabulary, grammar use, pronunciation, and pragmatics (appropriateness of responses). Computers are probably most advanced at this point in distinguishing pronunciation, but still trained phoneticians are used to diagnose and treat speech disorders, because software simply still isn't good enough. The variations you discussed are not well understood computationally or anatomically, so I don't believe there have been any good hypotheses other than those suggested by experience with children. [[User:SamuelRiv|SamuelRiv]] 04:02, 1 November 2007 (UTC)

:: Thanks SamuelRiv. I guess I wasn't as clear as I could have been. I was interested in specifically those differences that aren't linguistic in any way. That is, not vocabulary, grammar use, pronounciation or pragmatics, nor anything else for which it is require to assign meaning to the sounds. Rather, I wondered what kind of differences were recognisable in the pure sound-form of the voice, aucoustic qualities you might say. <p>
:: In any case, I found a paper which is along the lines of the ideas I expected : [http://cfpm.org/jom-emit/1998/vol2/vaneechoutte_m&skoyles_jr.html] : though it still seems that there is woefully little work done on understanding speech outside of pathological/dysfunctional cases, which I guess is understandable, if not totally satisfactory. [[User:81.153.3.36|81.153.3.36]] 12:09, 2 November 2007 (UTC) (Cross-posting to linguistics desk, just in case.)

== Things stuck in eyesocket ==

Suppose something small and mildly irritating (like, say, a bit of cat fur) got stuck up under someone's eyelid and worked up into the eye socket. What would happen to it? Would the body destroy it or expel it somehow? How long would it take? [[User:Maelin|Maelin]] <small>([[User talk:Maelin|Talk]] | [[Special:Contributions/Maelin|Contribs]])</small> 13:16, 31 October 2007 (UTC)m n
: In general, this idea falls apart when you expect something to work its way behind the eye. The eye, if I remember correctly, is pretty much sealed in the skull. There's no way to, for instance, lose a contact lens behind the eye. If you somehow DID get something behind the eye, it would have been through a wound, and the effects of that wound would be worse than the object itself, I should think. --[[User:Mdwyer|Mdwyer]] 14:39, 31 October 2007 (UTC)
::I guess it's possible something could embed itself up there and work its way in somewhat. I would expect a cat hair to be absorbed over a long period of time because it's protein, but anything inorganic...I shudder to think. And I suppose that the body would try to do to such a thing what it does to all such things, like splinters. The eye is different though; inflammation alone can be a serious matter. See ''sympathetic ophthalmia'' [http://www.tsbvi.edu/Education/anomalies/sympathetic.htm here] and [[Sympathetic ophthalmia|here]]. I doubt the body would have time to deal with an embedded cat hair before the eye reacted unfavorably to it. You can tell by my wishy-washy reply that I'm no expert. --[[User:Milkbreath|Milkbreath]] 15:43, 31 October 2007 (UTC)
:The function of the eyelashes would prevent a situation like this from occuring. Their job is to keep foreign objects out of the eye (i.e. dust, dirt, debris, cat hair). They work in conjunction with your tears to do it. Even though the primary function of the tears are to lubricate the eye, they also function as a sort of safety mechinism, when an object gets into the eye (be it dirt, dust, or cat hair) the eye gets irritated and tears up. The offender then gets caught up in the tears and then is eaither flushed out or it gets near the eyelid and caught by the eyelashes and taken out of the eye. Lastly, a thin, but strong, membrane, called the [[conjunctiva]], lines the inside of your eyelids and curls back on itself to cover the white part of the eye. This prevents any obects from going behind the eye. Hope this helps! [[User:Josborne2382|Josborne2382]] 16:18, 31 October 2007 (UTC)
::I've gotten specks of dust stuck between my eyelid and my eye. That's not quite behind the eye, but I still wonder how it always ends up getting out, and how I could get it out faster. — [[User:DanielLC|Daniel]] 03:26, 1 November 2007 (UTC)

== Hair loss ==

I asked my doctor about this but he didn't know exactly. I want to know if anybody has a link or two about uninterested reseaches on hair loss and effectiveness (if any) of treatments. I have quit given up hope on what constitutes medical advice so I'll just post fingers crossed and see if it gets deleted.[[User:193.188.46.254|193.188.46.254]] 14:03, 31 October 2007 (UTC)

:The [[baldness]] article has a huge list of the various possible prevention/reversal treatments: [[Baldness#Preventing_and_reversing_hair_loss]] -- [[User:Macaddct1984|MacAddct1984]] 14:10, 31 October 2007 (UTC)

== Freezing eye ==

Some time ago I read on how difficult it is for the eyes to freeze, but I forgot the reasons, could anybody patch me up on this? Also what would hypothetically hppend if you poured liquid nitrogen on somebodies eye? <small>—Preceding [[Wikipedia:Signatures|unsigned]] comment added by [[Special:Contributions/193.188.46.254|193.188.46.254]] ([[User talk:193.188.46.254|talk]]) 14:16, 31 October 2007 (UTC)</small><!-- Template:UnsignedIP --> <!--Autosigned by SineBot-->
: I'd guess it is because they're salty, and salt depresses the freezing point. Still, LN is going to make them freeze anyway. Don't do it. :) --[[User:Mdwyer|Mdwyer]] 14:34, 31 October 2007 (UTC)

:It also helps that the human eye is embedded in a nice warm human being, equipped with all kinds of tools to maintain the body at a fixed 37&deg;C. Heat is readily conducted from the back and sides of the eye socket (which, being right next to the brain, are well-supplied with nice, warm, constant-temperature blood) to the rest of the eye. Still, it would be possible to freeze the surface of the eye if you made enough of an effort&mdash;like by direct contact with a cryogenic liquid, for example. [http://www.uwm.edu/Dept/EHSRM/EHS/SARA/MSDS/nitrogen2001.pdf Tests in rabbit eyes] gave the result:
::''Liquid nitrogen poured onto the eyes for one or two seconds with the lids held apart, produced no discernable injury. When the exposure was extended to five seconds, slight lesions of the corneal were observed. By the next day, all eyes were entirely normal.''
:I would expect longer exposure to do progressively more damage. Assumptions about the behaviour of human eyes based on the rabbit model should of course be taken with a grain of salt. [[User:TenOfAllTrades|TenOfAllTrades]]([[User_talk:TenOfAllTrades|talk]]) 18:43, 31 October 2007 (UTC)
::Does it strike anyone else as odd that it is someone's job to pour chemicals into the eyes of rabbits? [[User:Man It's So Loud In Here|Man It&#39;s So Loud In Here]] 19:35, 31 October 2007 (UTC)
:::Rabbits are [[Draize test|commonly used in animal testing]]. -- [[User:Jsbillings|<span style="color:green">JSBillings</span>]] 20:04, 31 October 2007 (UTC)
::: Not at all, how else would we determine the safety and efficacy of drugs formulated as [[eye drop]]s? [[User:Rockpocket|<font color="green">Rockpock</font>]]<font color="black">e</font>[[User_talk:Rockpocket|<font color="green">t</font>]] 20:21, 31 October 2007 (UTC)
::::How many brands of eye drops have liquid nitrogen in them? I'm no PETA pusher, but that's just insanely and purposelessly cruel to the rabbits. What's the next experiment: tossing bunnies into a wood chipper? Maybe we'll develop a better bandaid from it. [[User:Matt Deres|Matt Deres]] 13:21, 1 November 2007 (UTC)

== Why do birds fly away from people? ==

I think this question is appropriate for the Science desk, since it seems to concern evolutionary biology. The question occurred to me this morning as I walked through a group of pigeons, which scattered as I approached them. This seems to be normal behaviour among our feathered friends, but when I stopped to ask myself why, I couldn't come up with an answer. In other words, why are birds scared of people? Of course, the answer that comes to mind first is that they are afraid of getting shot. Now, the chances of a pigeon being shot in a city street are pretty remote, although I guess the pigeon doesn't know that. So, is there some kind of evolutionary impulse at work here under which birds instinctively (and wrongly, in the case of city-dwelling birds) believe that man should be avoided? And if so, why hasn't this impulse atrophied among city-dwelling birds? --[[User:Richardrj|Richardrj]] [[User talk:Richardrj|<sup>talk </sup>]][[Special:Emailuser/Richardrj|<sup>email</sup>]] 14:25, 31 October 2007 (UTC)
:Well, not just birds run away from humans. I can't think of any animal, unless it's a pet or trained, that wouldn't run away from a human. Humans are fairly big mammals, and if you saw something 10x the size of you, it's more than likely to benefit you to run away from it. Why hasn't the behavior atrophied? Probably because there is no selective pressure to fade out the trait. If running away from humans suddenly had a negative impact, such as they all started getting hit by cars when they try and fly away, then it's more than likely to weed out the trait. In the meantime, the pigeons have nothing to lose by flying away from approaching humans. -- [[User:Macaddct1984|MacAddct1984]] 14:39, 31 October 2007 (UTC)
:Running/Flying away ([[Fight-or-flight response]]) is a pretty common behavior amongst animals. Not flying away from people is the unusual thing, probably bred into generations of city birds by the selective pressure of increased chance of food and less energy expense, as well as a lack of predators. Read about the [[Dodo]] to see what happens to a bird with few predators. -- [[User:Jsbillings|<span style="color:green">JSBillings</span>]] 14:40, 31 October 2007 (UTC)

:(After edit conflict) A general instinctive fear of being killed and eaten by a creature much larger than themselves? The street pigeons seem to mostly tolerate humans, seeing them as something to simply move out of the way of - as they understand from experience that the majority of the large bipeds of the concrete forest pay them little attention and mean them no particular harm. They only seem to become agitated and take flight (around here, at least) if a human is getting too close, actively following them around, trying to trap them up against a wall, or running/walking towards them at speed - all of which the bird may (rightly?) interpret as hostile acts. --[[User:Kurt Shaped Box|Kurt Shaped Box]] 14:43, 31 October 2007 (UTC)
::Great answers. Thanks all. --[[User:Richardrj|Richardrj]] [[User talk:Richardrj|<sup>talk </sup>]][[Special:Emailuser/Richardrj|<sup>email</sup>]] 14:53, 31 October 2007 (UTC)

:(another edit conflict) I think the 'rule' is probably more general than "man should be avoided" - something more along the lines of "if it's bigger than you and coming towards you, it should be avoided". Birds that tended to fly away when approached by something bigger than them would have an evolutionary advantage over those who hung around because that something may be a predator. Even if it's not a predator, it's extremely unlikely that it would be something that would provide the bird with some advantage over its fraidy-cat brethren who didn't stick around long enough to find out, so the wait-and-see trait would be disadvantageous and would die out. The impulse is still there because it's still advantageous, even amongst city-dwelling birds, to get out of the way of bigger things (imagine how odd would be if birds all wandered around on crowded streets, or didn't bat an eyelid if they were standing in the road and a car approached).
:In fact, not all birds take flight as soon as they're approached by a human. Before it was banned, holding a handful of seed in [[Trafalgar Square#Pigeons|Trafalgar Square]] was guaranteed to result in you being mobbed by pigeons. — [[User:Bewildebeast|Matt Eason]] <sup>([[User talk:Bewildebeast|Talk]] &#149; [[Special:Contributions/Bewildebeast|Contribs]])</sup> 14:58, 31 October 2007 (UTC)
::Yes, they're afraid because instinct tells them anything that gets close to them is probably trying to eat them! Although they are used to humans, they are still preyed upon by cats etc. Feral Pigeons are sufficiently tame to approach a human if they have food and some birds can be tamed so that they are not afraid of humans, my two pet budgies will run up to me and climb onto my hand if they are on the floor and I hold my hand out. It's just a case of convincing the bird that you are not going to harm it which takes time and perseverence. At the end of the day, one of the most basic instincts of all animals is to survive which means avoiding anything that is likely to be dangerous.[[User:GaryReggae|GaryReggae]] 15:01, 31 October 2007 (UTC)
:::Actually, some birds tend to be fond of humans. It was (and sometimes still is) for a human to be feeding food to gulls, pigeons, sparrows, ducks, geese, etc. Some other birds, especially flightless ones, are not afriad of humans. That's what killed the dodo so quickly. One time, for example, we were having a picnic. A small ~3 in. tall bird (not sure what it's called) came towards the food, and actually landed on the picnic table. If we tried to swat it away, it would fly away, hover in the air, and come back. It often landed about a foot away from us. Another time, we were just minding our own buisiness, and walking near the shoreline at a lake, when a few dozen ducks and geese who were near the shoreline seemed to follow us. As we walked by them, they continued to follow us. The moral of the story is, feeding of birds, even in the past, has caused some of them to follow humans and trust any food given by them. Now there are some laws restricting feeding of birds, but apparently the birds don't know that. Hope this helps. Thanks. ~<font color="blue">[[User:AstroHurricane001/A|A]][[User:AstroHurricane001|H]][[User:AstroHurricane001/D|1]]</font><sup>([[User:AstroHurricane001/T|T]][[Special:Contributions/AstroHurricane001|C]][[User:AstroHurricane001/U|U]])</sup> 23:49, 1 November 2007 (UTC)

== If human bodies had thick fur like other mammals, do you think we would still wear clothes? ==
[[Image:Nuremberg chronicles - Strange People - Hairy Lady (XIIv).jpg|thumb|She didn't. [[User:Rockpocket|<font color="green">Rockpock</font>]]<font color="black">e</font>[[User_talk:Rockpocket|<font color="green">t</font>]] 20:25, 31 October 2007 (UTC)]]
Do you? [[User:64.236.121.129|64.236.121.129]] 19:16, 31 October 2007 (UTC)

:Hmm, that's a fun question. It depends where our sense of modesty comes from. I would imagine without the invention of clothing and the ability to cover up, there would be no way for embarrassment of genitals to come about. However, clothing also provides an additional sense of style and individuality. So maybe, just being human, we'd wear some sort of clothing anyway -- [[User:Macaddct1984|MacAddct1984]] 19:47, 31 October 2007 (UTC)
::Individuality could be expressed by styling and coloring the fur, but I think clothing would still have been invented. Much of it provides a lot of utility beyond keeping warm. Lab workers, for example, would probably still wear some variation on a lab coat. Police officers would still wear Kevlar vests. I'm no expert, but it seems like if our current attitudes towards clothing evolved from the need to cover up in cold weather it wouldn't be surprising if other uses for clothed eventually evolved into similar attitudes. [[User:69.95.50.15|69.95.50.15]] 20:18, 31 October 2007 (UTC)

:Also where would you put your wallet if your a man? Certainly i'd still wear clothes, gotta have a place for my phone, keys, wallet and iPod...You can see why mugging is so popular! The above stuff is right too, clothes are cultural-identity too, they are also a sub-culture thing. Goths, punk rockers, skaters, sports-addicts, 'chavs', horse & hound types etc. A lot of clothes (and styles) seem to have started their life as work-based clothing and/or developed to become fashion/general wear. [[Jeans]] were work-clothes (still are), [[Cargo pants]], three-piece suit (though Adam Hart Davis suggests it was an attempt by the British to reduce the love of French clothing in the Stuart period), sports-wear is obviously often derived from sport-use clothing. Obviously work-wise these things are not just to cover modesty but as a form of protection/security/uniformity too [[User:Ny156uk|ny156uk]] 23:38, 31 October 2007 (UTC)

== How much sugar does the average kid/adult consume on Halloween? ==

^topic [[User:64.236.121.129|64.236.121.129]] 19:23, 31 October 2007 (UTC)

:Can you have an average kid or adult? <span style="border:1px solid #696969;background:#DCDCDC; padding:1px">[[User:Philc_0780|<span style="color:#696969;font-weight:bold">ΦΙΛ Κ</span>]]</span> 21:09, 31 October 2007 (UTC)

:Well you would expect that in any 'holiday' season people will allow themselves more treats, so possibly some like say three times as much as the 'average' sugar intake on any other day. This article (http://www.sys-con.com/read/451581.htm) is basically utter garbage but it does mention halloween and sugar intake. [[User:Ny156uk|ny156uk]] 23:33, 31 October 2007 (UTC)

::Ugh, I've heard stories of kids eating all their candy in one day, and there's often several hundred pieces of candy! No wonder people get sick and diabetes. Besides, if you're counting average as in world average, then the average kid doesn't go out for Halloween, either because the local culture doesn't celebrate it, and/or because the locals are too poor to afford that much candy. Besides, if you ate all your candy in one day, chances are a few of them may have been tampered with (I remember getting candy with the package opened). Some people argue that eating all your candy in one day has the same effect as eating it over a longer period. This is a complete falsehood. It might be a bit close to the truth if you're not going to have a single piece of candy or other treat for the next 6 months. Besides, eating all your candy in one day can cause blood sugar (and fat, and plastic, and colouring, etc) levels to suddenly spike up. It's kind of like drinking a gallon of alchohol in one day instead of the same amount over a 6-month peroid. Hope this helps. Thanks. ~<font color="blue">[[User:AstroHurricane001/A|A]][[User:AstroHurricane001|H]][[User:AstroHurricane001/D|1]]</font><sup>([[User:AstroHurricane001/T|T]][[Special:Contributions/AstroHurricane001|C]][[User:AstroHurricane001/U|U]])</sup> 23:58, 1 November 2007 (UTC)

== Cyanide and suicide ==

Is suicide via ingestion of cyanide, as seen in James Bond movies, fact or fiction? Babalonia 3. <small>—Preceding [[Wikipedia:Signatures|unsigned]] comment added by [[Special:Contributions/66.74.109.242|66.74.109.242]] ([[User talk:66.74.109.242|talk]]) 20:41, 31 October 2007 (UTC)</small><!-- Template:UnsignedIP --> <!--Autosigned by SineBot-->
:As can readily be found in our article on [[cyanide]], it can quite easily be used as a poison. [[Adolf Hitler]], among others, used it as such. &mdash; [[User talk :Lomn|Lomn]] 20:57, 31 October 2007 (UTC)
::When you say "as seen in James Bond movies" do you mean ingestion of cyanide causing death in seconds? [[User:Sifaka|<font color="Green">'''Sifaka'''</font>]] <sup>[[User talk:Sifaka|'''<font color="Green">talk</font>''']]</sup> 22:52, 31 October 2007 (UTC)
::I thought Hitler died from shooting himself (though his wife and dog were killed by cyanide pills). — [[User:DanielLC|Daniel]] 03:18, 1 November 2007 (UTC)
:::I think you're right. I'll hunt for a reference and fix the article. &mdash; [[User talk :Lomn|Lomn]] 14:27, 1 November 2007 (UTC)
::::The references in [[Adolf Hitler]] suggest that he both bit a cyanide capsule and shot himself, then had his body incinerated, just to be sure. &mdash; [[User talk :Lomn|Lomn]] 14:30, 1 November 2007 (UTC)
:::::Which do you think killed him? I don't care how fast cyanide can kill. A bullet to the brain would be faster. By the way, does bit a cyanide capsule mean he swallowed a pill, popped some kind of tiny balloon with his teeth, or what? — [[User:DanielLC|Daniel]] 01:54, 2 November 2007 (UTC)

== Exercising, Muscle Burn and Calories ==

Upon reading over several articles (such as [[muscle]] and [[exercising]] ), I’ve got a few questions relating to “muscle burn” after a rigorous workout. Assume that one runs a mile on a [[treadmill]]. Most treadmills indicate calories burned over the duration of the run. Further assume that, according to the treadmill, 200 calories are burned (let’s pretend this number is accurate). If the runner has muscle burn from the rigorous run, does he/she actually burn more calories than the 200 indicated by the treadmill? I would assume so, as the body is ‘recovering’ from the workout, and thus will burn additional calories post-run.

Thoughts?
[[User:Rangermike|Rangermike]] 21:25, 31 October 2007 (UTC)


:See [[Lactic acid]] and [[Delayed onset muscle soreness]], if you are referring to the fatigue and soreness one feels in one's muscles during and after workouts.

:This is out of my field, but the body is burning calories with everything you do, say, or feel, but nothing burns as quickly from homeostasis as physical motion. For a physicist's example, say you were sick, and you had a fever of one degree celsius. At a weight of about 100kg, you would burn 10^5 calories = 100 kcal (kilocalories or kcal are the actual unit of measure when people refer to "calories". One calorie properly refers to the heat necessary to raise the temperature of 1 gram of water by 1 degree celsius). Keep in mind, this fever builds up over several hours, whereas you can burn that much in a 30 minute workout. [[User:SamuelRiv|SamuelRiv]] 03:28, 1 November 2007 (UTC)

== Gravitational pull of the moon ==

Hi,<br>
I've heard that there is no instrument on the earth which can measure the gravitational pull of the moon (apart from the obvious affects of the tides). Is this true? --[[User:124.181.69.55|124.181.69.55]] 21:35, 31 October 2007 (UTC)

:Let's see here.... The Earth will pull on a 1 kg mass with a force of 9.8 newtons. Using an Earth-Moon distance of 380&nbsp;000&nbsp;km, the Moon overhead would tug on the same mass with a force of about 34 ''micro''newtons. So the apparent weight of an object due to the moon's motion over the course of a full lunar orbit will appear to vary cyclically over about 70 parts per million. That's not a huge amount, but it's certainly measurable. Particularly if one monitored a very stable, very precise balance over the course of several lunar orbits, I would expect the effect of the Moon's pull to stand out as a periodic oscillation. A very quick Google search for microgram balances finds [http://www.balances.com/sartorius/sartorius-le26p-micro.html this one], which will set you back about $7000, and which will measure masses up to 5 grams with a resolution of 2 micrograms (about 0.4 parts per million). Can someone check my numbers? [[User:TenOfAllTrades|TenOfAllTrades]]([[User_talk:TenOfAllTrades|talk]]) 22:05, 31 October 2007 (UTC)
::I get 7 ppm from your numbers (2 * 34e-6 / 9.8) &mdash; [[User talk :Lomn|Lomn]] 22:25, 31 October 2007 (UTC)
:In theory, there's no reason you can't. In practice, it may be the case that tolerances don't allow us to (I'm not sure). Just for reference, though, here's what you're dealing with. Gravitation is a function of mass over distance squared. For the Earth, we'll say that it's M/R<sup>2</sup>, where M is the mass of the Earth and R is the radius of the Earth, and we'll normalize that resulting number to 1. The Moon, on the other hand, masses roughly 1/80 Earth, and never gets closer (to the surface) than about 56R at perigee. Substituting, we expect that the Moon causes a discrepancy over a no-Moon Earth of 1/(80*56*56) -- that is, 4*10<sup>-6</sup> or 0.0004%. Now, in practice, that discrepancy can be roughly doubled -- the difference between the Moon directly overhead and directly underfoot (noting that the move from 56 to 58 Earth radii is pretty minor at this point). So in total, to detect the influence of the Moon's gravity on Earth-surface objects, you need accuracy to six digits, or one one-hundred-thousandth of the object. (ec) I notice that I'm an order of magnitude off Ten's answer. Time to double-check. &mdash; [[User talk :Lomn|Lomn]] 22:13, 31 October 2007 (UTC)
::I will note, however, that you're monitoring a periodic variation of [whatever the correct magnitude, 7 or 70 ppm] over a day, not a lunar orbit (month). Monitoring over the course of a month could be used to confirm the roughly 25% variation in the daily cycle resulting from the eccentricity of the Moon's orbit. &mdash; [[User talk :Lomn|Lomn]] 22:18, 31 October 2007 (UTC)

:::Oops, right. The Earth rotates once a day, doesn't it? Dang. Double oops; you're also right about the 7 ppm (not 70). I'm going to have to turn in my physics license. [[User:TenOfAllTrades|TenOfAllTrades]]([[User_talk:TenOfAllTrades|talk]]) 23:02, 31 October 2007 (UTC)

:[[LIGO]] has to compensate for lunar tides, so there is an example of an active experimental instrument that is sensitive to the moon's gravity. [[User:Dragons flight|Dragons flight]] 23:43, 31 October 2007 (UTC)

:They did it on [[MythBusters %28season 4%29#Episode 68 .E2.80.94 .22Anti-Gravity Device.22|an episode of mythbusters]]. They used an extremely powerful accelerometer to measure if the anti-gravidy contraptions had any effect whatsoever (they didn't). They breifly mentioned the accelerometer measuring the tidal forces from the moon and showed the graph it made. — [[User:DanielLC|Daniel]] 02:01, 1 November 2007 (UTC)

:You may be confusing an important law in [[Special Relativity]], which states that a person in a closed space can never tell whether he is being accelerated due to external gravity or some other outside force (such as a rocket). See the article for details. You may also be thinking of the [[Cavendish experiment]], in which the gravitational force of the moon, the planets, and the Earth were all simultaneously measured by measuring the [[gravitational constant]] G, which combined with Newtonian orbit theory gives everything you could possibly want about gravitational forces in the solar system. [[User:SamuelRiv|SamuelRiv]] 03:27, 1 November 2007 (UTC)

:The "apart from the tides" part of the question is pretty telling though. If a simple yardstick stuck into the sand at the low tide mark can detect the presence of the moons gravity, it's unlikely that there would be nothing else that could do the job. [[User:SteveBaker|SteveBaker]] 01:15, 2 November 2007 (UTC)

::The tides are a tiny deformation in the earth. A proportional deformation on an artificial device would be ridiculously small. Measuring the tides with an accelerometer is essentially the same as measuring height above sea level to the meter with one. Although what anon heard is wrong, it's not particularly misleading. — [[User:DanielLC|Daniel]] 01:51, 2 November 2007 (UTC)

:I'm sorry, my point wasn't clear -- all you need to measure the gravitational pull of the moon is Newtonian gravitation (i.e. [[Kepler's laws of planetary motion|Kepler's Laws]]) and a measure for G (Cavendish). Then from Earth using parallax or radar we can calculate the Earth-Moon distance, and we know the period of the Moon's orbit around Earth and so we can calculate the mass of the Moon, and the Gravitational field of the Moon is then <math>\frac{-G*M}{r^2}</math>, where M is the mass of the Moon and r is the Earth-Moon distance. [[User:SamuelRiv|SamuelRiv]] 02:15, 2 November 2007 (UTC)

== [[oxidizer]]s ==

are they flamible without fuel?
:Various ether [[peroxide]]s, like [[Acetone peroxide]], [[Diethyl ether peroxide]], and [[Tetrahydrofuran]] peroxide [[contact explosive|spontaneously explode]] when disturbed. Lab accidents involving such peroxides formed when a bottle of ether is exposed to light, oxygen, or catalytic metals and then subsequently ignored for a long time happen every once in a while. [[User:Sifaka|<font color="Green">'''Sifaka'''</font>]] <sup>[[User talk:Sifaka|'''<font color="Green">talk</font>''']]</sup> 23:15, 31 October 2007 (UTC)
::Thinking more about this, I bet some oxidizing agents with more complex chemical structures could react with themselves or other molecules of the oxidizer. There are probably also some nasty chemicals which have the potential to react under a variety of storage conditions without deliberately added fuel. [[User:Sifaka|<font color="Green">'''Sifaka'''</font>]] <sup>[[User talk:Sifaka|'''<font color="Green">talk</font>''']]</sup> 23:28, 31 October 2007 (UTC)

== oxidation ==

is mn203 a good pyrotechnic oxidizer? <small>—Preceding [[Wikipedia:Signatures|unsigned]] comment added by [[Special:Contributions/216.103.183.127|216.103.183.127]] ([[User talk:216.103.183.127|talk]]) 21:59, 31 October 2007 (UTC)</small><!-- Template:UnsignedIP --> <!--Autosigned by SineBot-->
:I'm not getting any hits on google for [[manganese (III) oxide]] (also called manganese sesquioxide) being used as a pyrotechnic oxidizer. Safety precautions for the compound as listed in the sigma aldritch catalog ([http://www.sigmaaldrich.com/catalog/search/ProductDetail/ALDRICH/463701/ source]) list it as an irritant to eyes, respiratory system and skin so I doubt people would appreciate it being scattered about by pyrotechnic displays where it could be inhaled. Among the applicable safety phrases it says don't add water to it. Of important note is that sigma didn't list it as an oxidizer, so I am leaning towards doubting its efficacy as an oxidizer at this point (I need to research around a little more). Many other manganese compounds appear to be fairly strong oxidizers including [[Manganese(III) acetate]]. Perhaps you meant to ask about one of them instead? Try looking at the [[manganese]] page. [[User:Sifaka|<font color="Green">'''Sifaka'''</font>]] <sup>[[User talk:Sifaka|'''<font color="Green">talk</font>''']]</sup> 23:58, 31 October 2007 (UTC)

== Tased across the spine ==

Can a person be paralyzed if the electrodes are opposite the spinal cord? I recently saw a video of someone getting tased in the back (the flying wires kind, not the little zapper kind) and it made me wonder --[[User:Froth|<span style="text-decoration: overline underline;">'''ffroth'''</span>]] 22:14, 31 October 2007 (UTC)

:See [[Taser]] for details. The weapon uses a shaped electric current to disrupt nerve function, I suppose in a process similar to a localized seizure. Unless structural damage occurs to nerve fibres or bone, the current itself shouldn't produce permanent effects. The brain and spinal cord both have a certain degree of plasticity (ability to change - i.e. learning) that is believed to depend on the intensity and duration of electric currents. See [[Electroconvulsive Therapy]] for information on the effects of high-intensity electric currents on the brain. Permanent effects to the spinal cord could possibly be similar, but would only affect memories stored in the spine, namely "muscle memory". <small>—Preceding [[Wikipedia:Signatures|unsigned]] comment added by [[User:SamuelRiv|SamuelRiv]] ([[User talk:SamuelRiv|talk]] • [[Special:Contributions/SamuelRiv|contribs]]) 03:38, 1 November 2007 (UTC)</small><!-- Template:Unsigned --> <!--Autosigned by SineBot-->

:My answer is "Sure, why not?" We tend to think of a relatively robust person getting tased, but suppose a frail child gets in the way? The darts can penetrate up to an inch, and from what I saw poking around the internet, you get millisecond-range currents of up 8.5 amps. That's a lot of current, however short the pulse. If the darts get deflected so that they land right next to each other on either side of the spinal cord, I wouldn't be surprised if it caused electrical burns in the tissue in between. It was hard to get solid information on electrically caused tissue damage by googling, and I don't know much about the specific direct effects of the taser waveform on soft tissue. There is a lot of propaganda out there spewed by parties with an interest in tasers, for marketing, for furthering the use of non-lethal force by police, and for opposing tasering as an invitation to police excesses. The truth has been effectively obscured on the internet, it seems. --[[User:Milkbreath|Milkbreath]] 10:34, 1 November 2007 (UTC)

::Well, when we got our Taser's late last year, we all had to "take a shot" to carry them, I have video's of it all. AFAIK every charge was administered via clipping one probe to the right rear shoulder, and one probe on the left pants pocket cuff, then having 2 people hold onto the victi... er administeree's arms. I'd consider that across the spine, no ill effects from any of us(though thats not to say it isn't possible, I believe elderly people or pregnant woman is what our SOP say to try to avoid tasing), minus the videos floating around of us yelling 'oh fuuuuuuuu', and yes I am not ashamed to admit I screamed like a baby and being in that large of a muscle mass it really takes a lot out of you. Yes, I had what appeared to be tissue burns on the spots where the probes were, they went away after about 2 days, and I can say there was no pain there, even the second the charge was up, I felt shaky but nothing else. Even out support staff (dispatch, admin aide, records clerk, evidence tech) all volunteered to take a shot, and yes, the women did seem quieter than the guys. [[User:Dureo|Dureo]] 11:00, 1 November 2007 (UTC)
::Oh and remember, the probes can penetrate deeper in winter, there are specifically longer winter probes for winter clothing, and yes unless they are torn out as they fall we have EMS handle removing them. [[User:Dureo|Dureo]] 11:04, 1 November 2007 (UTC)

== secret service mobiles ==

Just curious about how this locking down on mobile signal works and how do the mobiles that are manufactured against it work.[[User:88.203.105.48|88.203.105.48]] 22:42, 31 October 2007 (UTC)

:When a police service says they're locking down the mobile phone system (usually because of a [[bomb threat]]), they generally mean that they're ordering the mobile phone companies to stop routing phone calls to mobiles in the relevant area. It stops people using a mobile phone to trigger a bomb. Aside from that, I'm not really certain that that's what you're asking. Can you be more clear (for example, can you post a link to a website or news article that spurred you to asked the above question)? --[[User:Psud|Psud]] 10:18, 1 November 2007 (UTC)

:It's all just a matter of software. Every phone has it's own unique number - the cell towers know the numbers of the phones in their area. In case of an emergency, the computer in the cell towers can decide what they want to do with calls. If it's an emergency, it could (for example) stop routing calls from any phone that's not listed as belonging to an emergency worker. This stuff is very easy to do if you have the inclination. [[User:SteveBaker|SteveBaker]] 01:08, 2 November 2007 (UTC)

By locking down I meant pin point the location of the user of the mobile [[User:193.188.46.254|193.188.46.254]] 09:18, 2 November 2007 (UTC)

:They used to locate mobile phones by asking the phone company which phone towers it was communicating with, mobile phones keep in contact with several towers to allow instant handover as you move between cells. It's a simple matter of looking for the phone/person in the area where the various towers' signals overlap. That's the simple version anyway (and I don't know enough to give you the complicated one). The new way they look for phones is by asking the phone for its GPS position. Only works with phones with GPS. The old method works with any phone, I think. Perhaps it could be defeated by hacking the phone so it talks to the "wrong" mobile phone towers. It'd probably be trivial to hack a GPS equipped phone to report a wrong location. --[[User:203.22.236.14|203.22.236.14]] 09:58, 2 November 2007 (UTC)

== Rising Sea Levels and the Effect this Will Have on the Mediterranean Ocean ==

Given that the Med is regarded (more or less)as a tideless sea and that this is largely due to the influence of the Straits of Gibraltar which constrict the tidal bulge caused by the gravitational pull of the sun and/or the moon. At what point, if at all, or to what degree, in the earths future, will the Med see a real tidal effect once the seas have risen enough to overcome the resistance of the Straits of Gibraltar? Much of the Med coastline is at or very near sea level because there has never been any need to make allowances for tidal fluctuations. <small>—Preceding [[Wikipedia:Signatures|unsigned]] comment added by [[Special:Contributions/79.68.42.88|79.68.42.88]] ([[User talk:79.68.42.88|talk]]) 23:08, 31 October 2007 (UTC)</small><!-- Template:UnsignedIP --> <!--Autosigned by SineBot-->

:Well much of all society is near the sea/lakes because historically we settled near places with ready access to water. The med problem is interesting. I expect it would require an extremely large increased. As the article ([[Strait of Gibraltar]]) notes water depth ranges from 300m to 900m, the opening is some 8 miles wide - having said this the end of the article has a bit on the 'need for a dam' so might be worth having a look at that link (http://www.agu.org/sci_soc/eosrjohnson.html) [[User:Ny156uk|ny156uk]] 23:28, 31 October 2007 (UTC)

== facial hair ==

Why do males have facial hair? Why don't females? <small>—Preceding [[Wikipedia:Signatures|unsigned]] comment added by [[Special:Contributions/68.231.151.161|68.231.151.161]] ([[User talk:68.231.151.161|talk]]) 23:45, 31 October 2007 (UTC)</small><!-- Template:UnsignedIP --> <!--Autosigned by SineBot-->

:Vestigial trait. Doesn't serve any meaningful purpose unless you are white, it can sort of protect the face from UV radiation, but melanin (dark skin) does a much better job of that, and protects everywhere. So in other words, it's useless from a utilitarian point of view, but has cultural and social significance. [[User:Malamockq|Malamockq]] 01:24, 1 November 2007 (UTC)
::[[Facial hair]] is a [[secondary sex characteristic]] resulting from the differential effects of [[sex hormone]]s on the body. [[User:Rockpocket|<font color="green">Rockpock</font>]]<font color="black">e</font>[[User_talk:Rockpocket|<font color="green">t</font>]] 07:50, 1 November 2007 (UTC)
:::[[Bearded lady|Some women]] do have facial hair. -- [[User:Jsbillings|<span style="color:green">JSBillings</span>]] 10:25, 1 November 2007 (UTC)
::: In theory it helps to protect against the cold in high northern places like Scandanavia or Russia. As to why women dont, I dont know. But look at most antarctic scientists, they have big beard for the cold. If you have hair, when was the last time your head got cold? <small>—Preceding [[Wikipedia:Signatures|unsigned]] comment added by [[Special:Contributions/12.191.136.2|12.191.136.2]] ([[User talk:12.191.136.2|talk]]) 15:08, 1 November 2007 (UTC)</small><!-- Template:UnsignedIP --> <!--Autosigned by SineBot-->

== Finite from Infinite ==

Today's science dictates that not only is a theoretical construct of infinite density, energy, and size possible; it's actually how the universe started. How does a finite universe come from something that is infinite? <small>—Preceding [[Wikipedia:Signatures|unsigned]] comment added by [[User:Sappysap|Sappysap]] ([[User talk:Sappysap|talk]] • [[Special:Contributions/Sappysap|contribs]]) 23:55, 31 October 2007 (UTC)</small><!-- Template:Unsigned --> <!--Autosigned by SineBot-->

:Firstly, there is no accepted theory suggesting the Universe is finite. While the ''observable'' universe is quite finite, the actual universe is possibly infinite in extent and mass. Further, physics ''does not'' posit that the universe began in a state of infinte density. It actually doesn't posit anything accepted about where it came from, as the [[Big bang]] theory ''only'' deals with what happened ''after'' (very soon after, though) the universe started existing. [[User:Someguy1221|Someguy1221]] 00:27, 1 November 2007 (UTC)
::Thirdly one way to look at it is fintite mass divided by zero size gives infinite denisity. [[User:Graeme Bartlett|Graeme Bartlett]] 00:30, 1 November 2007 (UTC)
::I'm a huge fan of all of you guys who answer these questions...Someguy1221, Rockpocket, SteveBaker, Dragon's Flight and the whole crew. Please have infinite patience with me while I ask the following: How can the universe have infinite mass without infinite density? How can it have infinite extent and continue to expand? [[User:Sappysap|Sappysap]] 01:07, 1 November 2007 (UTC)

:::As for the first, I'm still trying to get my head around it, but for the second, imagine a piece of elastic, infinitely long, with small knots tied at regular intervals. Now imagine the elastic being stretched - you'll see the knots moving apart, even though you can't see the "ends" moving apart. [[User:ConMan|Confusing Manifestation]] 02:00, 1 November 2007 (UTC)

::::To answer how the universe can have infinite mass without infinite density, all you have to do is think of numbers. There are infinitely many integers, as I'm sure you're well aware. There are also infinitely many numbers inbetween every two integers. And so, you manage to have a system of infinitely many numbers containing an infinite number of ''integers'' yet not every number is an integer. Actually, as you might suspect from there being infinitely many numbers between two integers, and only finitely many integers between any two numbers, each integer is like a tiny island in the sea of infinity. So, in conclusion, your infinitely many integers occupy an ''infinitely small'' portion of the number line. So I think you can see from this how you can have, in an infinitely large universe, infinitely many masses without filling up every possible space with a particle. As for having infinite extent, I haven't quite figured or accepted that one yet, except to say that lots of astronomers believe this (it is in part just a conclusion from the evidence that the Universe has no center or edge). [[User:Someguy1221|Someguy1221]] 02:33, 1 November 2007 (UTC)

:::The universe has infinite mass if and only if it has infinite volume. Obviously everything around us has finite density, but if you allow yourself to collect more and more of it without limit, then ultimately you arrive at an infinite amount occupying an infinite volume. It is unknown whether the universe is truly infinite in extent, but it appears likely that it must be very much larger than the [[observable universe]] we can see. [[User:Dragons flight|Dragons flight]] 03:26, 1 November 2007 (UTC)

:None of the above physical quantities are or ever were truly infinite. The widespread modern [[cosmologies]] (that is, those based on [[Einstein]]’s [[general relativity]], which came out about 90 years ago) all involve a universe that is finite in size and energy (or mass). And I’m talking about the entire universe, not just the visible universe. It isn’t really accurate to say that the density of the universe was infinite at the exact moment of the [[big bang]], either. [[Singularities]] in a physical theory generally indicate a point at which the physical model breaks down, not that there really is an infinite physical quantity at that point. In this case, physics within the [[Planck epoch]] are poorly understood, but it appears that it is meaningless to talk about distances less than one [[Planck length]], which is a finite distance, or time intervals shorter than the [[Planck time]], which is also finite. So it isn’t meaningful to talk about energy densities greater than the (finite) total energy of the universe divided by the volume of a sphere whose diameter is a Planck length, or meaningful to talk about the exact instant of the big bang. [[User:MrRedact|MrRedact]] 02:46, 1 November 2007 (UTC)

::I'm not sure what the initial question refers to, specifically. There are indeed important resolutions of infinite results in [[Quantum Field Theory]], which I might be able to expand upon if a detailed question is posted, but all "physical" results must be finite by definition. Unresolved singularities (infinite results) signify a failure of a theory, not a physical reality. Cosmology works a little differently, but even then most cosmologies I know of do not accept any premise of infinity except perhaps in the context of a ground state (see [[vacuum]]). [[User:SamuelRiv|SamuelRiv]] 03:45, 1 November 2007 (UTC)

::You are confused. [[General relativity]] permits solutions that are either infinite or finite in extent, and so is essentially agnostic on the issue. (See for example: [[Friedmann-Lemaître-Robertson-Walker metric]], which permits different homogeneous and isotropic solutions discriminated primarily by whether the universe is finite or not.) For the universe to be finite, it must have a global curvature such that a person traveling in what appears to him to be a straight line will eventually come back to places he has been before. Such a curvature is possible, but not required, in GR. Your description of the Planck quantities is also problematic. It is not that there couldn't theoretically be smaller lengths, times, etc., but rather that describing events at those scales intrinsically requires both an unified understanding of gravity and [[quantum mechanics]]. In other words it requires an as yet ill-defined theory of [[quantum gravity]]. So, it is meaningless primarily in the sense that science as it now exists is not able to provide it meaning. Future theories may yet shine a light on events in and before the [[Planck epoch]]. [[User:Dragons flight|Dragons flight]] 04:09, 1 November 2007 (UTC)
:::Ouch. I should have researched this one a little better before responding. I’m obviously not an expert in cosmology. Einstein himself assumed [[Closure (mathematics)|closed]] [[boundary conditions]] on his [[Einstein field equations|field equations]], which implies a finite universe, but what slipped my mind for some reason was that not everyone assumes those boundary conditions.

:::My description of the Planck quantities very closely echoes a sentence in the [[Planck epoch]] article: "When quantum mechanics is combined with gravity, it turns out that it is meaningless to speak of time intervals shorter than the Planck time or distances shorter than one Planck length." That sentence, at least, is consistent with my understanding that "space" and "time" are ill-defined concepts at shorter times and distances. Of course, it’s all highly speculative, in the absence of a good theory of quantum gravity. [[User:MrRedact|MrRedact]] 10:36, 1 November 2007 (UTC)

= November 1 =

== What Are Some Things All Things On Earth Have In Common That Are Living Or Non-Living? ==

I wonder, what are some things all things on Earth have in common that are living or non-living? <small>—Preceding [[Wikipedia:Signatures|unsigned]] comment added by [[Special:Contributions/208.103.143.9|208.103.143.9]] ([[User talk:208.103.143.9|talk]]) 03:07, 1 November 2007 (UTC)</small><!-- Template:UnsignedIP --> <!--Autosigned by SineBot-->

:Please clarify your question. Everything is living or non-living. — [[User:DanielLC|Daniel]] 03:15, 1 November 2007 (UTC)
:They're all made up of atoms? -- [[User:Macaddct1984|MacAddct  1984]] <sup>([[User talk:Macaddct1984|talk]] &#149; [[Special:Contributions/Macaddct1984|contribs]])</sup> 03:19, 1 November 2007 (UTC)
::Not everything is made up of atoms. [[Evidence_of_evolution#Evidence_from_comparative_physiology_and_biochemistry]] lists many things that living things mostly have in common. As for non-living things, their only binding similarity is that they aren't living. [[User:Someguy1221|Someguy1221]] 03:21, 1 November 2007 (UTC)
:They're all made of matter and/or energy, they're all affected by the laws of physics, and they all hate getting [[circus peanuts]] on [[Halloween]]. ;-) -- [[User:HiEv|<span style="color:#E05858;font-weight:bold;">Hi</span>]][[User talk:HiEv|<span style="color:#C06060;font-weight:bold;">Ev</span>]] 04:07, 1 November 2007 (UTC)

Everything came from a star. --[[User:DHeyward|DHeyward]] 13:43, 1 November 2007 (UTC)

:Everything? I'd be willing to bet that there's a great deal of [[primordial hydrogen]] floating around right now. --[[User:Carnildo|Carnildo]] 23:55, 1 November 2007 (UTC)

::What part of ON EARTH, didn't you get? [[User:64.236.121.129|64.236.121.129]] 13:38, 2 November 2007 (UTC)

== Contradiction in mass-to-energy equivalence? ==

I'm new at Wikipedia editing and whatnot, so I wasn't sure where I should put this where it would be noticed:


----

''The article "Antimatter Weapon" states:''

Quantities measured in grams or even kilograms would be required to achieve destructive effect comparable with conventional nuclear weapons; one gram of antimatter annihilating with one gram of matter produces 180 terajoules, the equivalent of 43 '''kilotons''' of TNT.

----

''The article "TNT equivalent" states:''

By E = mc^2, when 1 kilogram of antimatter annihilates with 1 kilogram of matter the reaction produces 1.8×10^17 J, which is equal to 42.96 '''Mt'''.

----


While I could just do the basic equation (mass*c^2, and convert joules to TNT equivalence), I didn't want to make an assumption without consulting anyone else first lest I made a mathematical error or overlooked some other factor in the calculation. <small>—Preceding [[Wikipedia:Signatures|unsigned]] comment added by [[Special:Contributions/24.65.12.157|24.65.12.157]] ([[User talk:24.65.12.157|talk]]) 04:44, 1 November 2007 (UTC)</small><!-- Template:UnsignedIP --> <!--Autosigned by SineBot-->

:1 kilogram is 1000 grams; 1 Mt (megaton) is 1000 kilotons. Is that what you are confused about, or is there something else? [[User:Dragons flight|Dragons flight]] 04:48, 1 November 2007 (UTC)
::Ugh. I missed the "one gram" versus "1 kilogram" part. Well, we all make mistakes. C'est la Vie. <small>—Preceding [[Wikipedia:Signatures|unsigned]] comment added by [[Special:Contributions/24.65.12.157|24.65.12.157]] ([[User talk:24.65.12.157|talk]]) 04:54, 1 November 2007 (UTC)</small><!-- Template:UnsignedIP --> <!--Autosigned by SineBot-->

== Medical question ==

'''Deleted.''' [[User:William Ortiz|William Ortiz]] 08:38, 1 November 2007 (UTC)
:Sorry, but this page isn’t a place to ask for medical advice, either. As it says at the top of the page: "'''Do not request regulated professional advice'''. If you want to ask advice that "offline" would only be given by a member of a licensed and regulated profession (medical, legal, veterinary, etc.), do not ask it here. Any such questions may be removed. See [[Wikipedia:Medical disclaimer]] and/or [[Wikipedia:Legal disclaimer]]. Ask a '''doctor''', dentist, veterinarian or lawyer instead." [[User:MrRedact|MrRedact]] 09:04, 1 November 2007 (UTC)


Do you know where on the internet they give medical advice? [[User:William Ortiz|William Ortiz]] 09:11, 1 November 2007 (UTC)

:Here, if you're careful to hide the request for medical advice by disguising it as a question of biology, anatomy or the way medical devices work. But you've given the game away now, so I doubt you'd have much luck asking the same question again (by the way, I think what you suggest (a) wouldn't work, and (b) would be a bad idea). Actually, a [http://www.google.com/search?q=medical+advice&ie=utf-8&oe=utf-8&aq=t&rls=com.ubuntu:en-US:official&client=firefox-a google search] would help you find online medical advice. --[[User:Psud|Psud]] 10:32, 1 November 2007 (UTC)

::[http://www.nhsdirect.nhs.uk/ NHS Direct] is a good place to start.--[[User:Shantavira|Shantavira]]|[[User talk:Shantavira|<sup>feed me</sup>]] 12:50, 1 November 2007 (UTC)

== [[Big Bang]] ==

Was the [[Big Bang]] a chain reaction? [[User:kadiddlehopper|<small><i><font color="brown">Clem</font></i></small>]] 09:59, 1 November 2007 (UTC)

:If by "chain reaction" you mean a [[nuclear reaction]] then the answer is no, because protons and neutrons did not begin to form until about a millionth of a second ''after'' the Big Bang, and they did not begin to combine into stable nuclei until about 1 minute or so after the Big Bang - see our articles on the [[hadron epoch]] and [[Big Bang nucleosynthesis]]. [[User:Gandalf61|Gandalf61]] 11:40, 1 November 2007 (UTC)
::Of course not <s>silly</s> bro. How can there be a chain reaction with particles not yet formed? I'm talking about with whatever was formed. Did it have a chain reaction? [[User:kadiddlehopper|<small><i><font color="brown">Clem</font></i></small>]] 14:05, 1 November 2007 (UTC)
:::There's no need to call a volunteer "silly" for answering your question as phrased -- especially when he then expands your question to give you exactly the answer you wanted. It's rather rude and quite unwarranted. Another example of what Gandalf linked is at [[Timeline_of_the_Big_Bang#Nucleosynthesis|timeline of the Big Bang]], particularly the 17-minute period of nucleosynthesis which established the initial ratio of hydrogen to helium. &mdash; [[User talk :Lomn|Lomn]] 14:21, 1 November 2007 (UTC)

:I think most interactions that occurred immediately after the big bang--quark-gluon interactions to form nucleons and nucleons and leptons forming atoms--are not chain reactions because there are no particle emissions necessary any of these reactions - a chain reaction is a series of reactions that require as input some output from a previous reaction, so that the previous allows the next to occur and so on. So I would say the answer is no in general, but specific reactions might be catalyzed from energy or lepton release by some of these primitive interactions. [[User:SamuelRiv|SamuelRiv]] 14:28, 1 November 2007 (UTC)

::I suppose I'm thinking more in terms of instances of interrupted stability wherein under different circumstances some changes might not occur at all or occur as rapidly except for the occurrence of previous events such that event of type "B" will cease to occur if and when event of type "A" ceases to occur. Maybe "sequence of dependent events" is more apt terminology than "chain reaction". [[User:kadiddlehopper|<small><i><font color="brown">Clem</font></i></small>]] 17:09, 1 November 2007 (UTC)

:::Okay then, you are asking a very general question. All big-bang cosmologies that I know of come from very fundamental fluctuations in the background. A fluctuation may create a [[false vacuum]], for example, and the cosmological effects are calculated from that state alone. So everything follows from this one single event, and yes, from there everything is dependent on what comes before. Caveat--the notion of [[dark energy]] may prove that some critical events in the universe's history are ''not'' caused by a "sequence of dependent events". [[User:SamuelRiv|SamuelRiv]] 02:24, 2 November 2007 (UTC)

== "Superlinear" ==

First things first, hi desk, long time no see!
Anyone have any idea what this word "superlinear" means? My first guess would be a function that increases faster than a linear function, but then you can of course have an incredibly steep linear function. A friend of mine asked me in the context of a biological function. Can someone clarify? It's not something that i've heard in my undergraduate career. Google has a load of results but none of them are very clear from what I can see. Could it be a function that is more linear than a linear function? That makes no sense to me either.
Math board, maybe? :? <small>—Preceding [[Wikipedia:Signatures|unsigned]] comment added by [[User:Capuchin|Capuchin]] ([[User talk:Capuchin|talk]] • [[Special:Contributions/Capuchin|contribs]]) 11:59, 1 November 2007 (UTC)</small><!-- Template:Unsigned --> <!--Autosigned by SineBot-->
Cheers, [[User:Capuchin|Capuchin]] 11:39, 1 November 2007 (UTC)

:When describing functions, "superlinear" appears to mean a function with [[asymptotic]] growth that is more than linear i.e. it grows faster than any multiple of ''x'' (there is a different, but related, usage in "superlinear convergence"). Superlinear functions include functions such as ''x''<sup>2</sup> or indeed any power of ''x'' greater than 1, also ''x''<sup>''x''</sup>, and functions such as ''x''log(''x''), ''x''log(log(''x'')) etc. Note that even a "steep" linear function will eventually be overtaken by a superlinear function - if f(''x'')=''Ax'' and g(''x'')=''Bx''<sup>2</sup>, then no matter how large you make ''A'' and how small you make ''B'' you can always find a lower limit ''y'' such that g(''x'') > f(''x'') for all ''x''>''y''. [[User:Gandalf61|Gandalf61]] 12:04, 1 November 2007 (UTC)

::Okay thank you, that's what I had assumed. [[User:Capuchin|Capuchin]] 12:10, 1 November 2007 (UTC)

== Do all the biochemical reactions happened in our body have a negative free energy? ==

I am a high school student.
Yesterday, my teacher teacher give us a question written: Do all the biochemical reactions happened in our body have a negative free energy. Explain and support your answer.
I don't know how to answer it. Any one can help. Thx in advance!! <small>—Preceding [[Wikipedia:Signatures|unsigned]] comment added by [[Special:Contributions/202.40.139.171|202.40.139.171]] ([[User talk:202.40.139.171|talk]]) 12:32, 1 November 2007 (UTC)</small><!-- Template:UnsignedIP --> <!--Autosigned by SineBot-->
:Wikipedia has articles such as [[Gibbs free energy]] and [[enzyme kinetics]], but they either do not address your question or they do not address it in plain English. [http://www.ncbi.nlm.nih.gov/books/bv.fcgi?highlight=energy,Gibbs&rid=stryer.section.156#167 This biochemistry textbook] has a standard treatment of free energy in biochemical reactions for college students. If you are not ready for the math skip down to, "the free-energy change must be negative for a reaction to be spontaneous." The complication in biochemical systems is that there are many "coupled reactions" in which one chemical reaction that has a positive free energy change is "driven" by coupling it to a second chemical reaction that has a negative free energy change. Example: [[Glyceraldehyde 3-phosphate dehydrogenase#Two-step conversion of glyceraldehyde 3-phosphate|Two-step conversion of glyceraldehyde 3-phosphate]]. So the answer to "Do all the biochemical reactions happened in our body have a negative free energy?" depends on how you define "biochemical reaction". If you define "biochemical reaction" to include '''both''' of the chemical reactions in a pair of biochemically-coupled chemical reactions then yes, the combined free energy changes of the two chemical reactions are negative. If you define each of the individual coupled chemical reactions to be its own "biochemical reaction", then it is clear that some individual chemical reactions that take place in biochemical systems have a positive free energy and you could call those "biochemical reactions". --[[User:JWSchmidt|JWSchmidt]] 15:45, 1 November 2007 (UTC)

:If you have a library card you can get help with homework [http://www.brooklynpubliclibrary.org/homework_help.jsp here]. [[User:71.100.9.205|71.100.9.205]] 14:14, 1 November 2007 (UTC)

:Put it another way: do all biochemical reactions in the body happen spontaneously? That is, do they all occur as soon as it is possible for them to occur? Think about what this would mean. [[User:SamuelRiv|SamuelRiv]] 14:32, 1 November 2007 (UTC)
::[[Spontaneous human combustion]]? [[User:kadiddlehopper|<small><i><font color="brown">Clem</font></i></small>]] 18:40, 1 November 2007 (UTC)
* SamuelRiv makes a very good point. (see [[Enzyme]]) - [[User:MacGyverMagic|Mgm]]|[[User talk:MacGyverMagic|<sup>(talk)</sup>]] 09:18, 2 November 2007 (UTC)

== Blood phobia ==

How do extremely [[hemophobia|hemophobic]] women cope with getting their [[menstruation|period]]? --[[User:124.254.77.148|124.254.77.148]] 13:11, 1 November 2007 (UTC)

:With great difficulty I would imagine. Your question sort of reminded me of the [[Ashley Treatment]]. Short of [[hysterectomy]] or [[Endometrial ablation]], I suppose they could ''reduce'' the number of periods they have using one of the many pills, but would still have to go through a few. Alternatively, maybe frequent exposure reduces the horror? [[User:Skittle|Skittle]] 13:48, 1 November 2007 (UTC)
:*FYI, the only reason women still have periods while on [[birth control pills]] is that some of them are [[placebo]]s. For years, many women doctors have taken real BC all month long, and thereby never have periods at all. The FDA has recently started allowing [[Extended cycle combined oral contraceptive pill|such regimens]] to be marketed. --[[User:TotoBaggins|Sean]] 19:40, 1 November 2007 (UTC)

== constraints based on age ==

Is there a chart of minimum and maximum amounts (or rates) of oxygen, water, food, temperature, blood, exercises, heart rate, Vitamins, etc. within which the human body must stay to survive at different ages? For instance, heart rate probably has a narrower range for older people than for younger people as well as exercise, etc. [[User:71.100.9.205|71.100.9.205]] 13:23, 1 November 2007 (UTC)

== Exercise/muscle Pain ==

Why do personal trainers insist on creating so much pain for a person that hasn't exercised in a long while? What I mean is what benefit comes from torturing someone to the point that the next day they can't even climb stairs without extreme muscle soreness. I would think that muscle gain should be built up slowly over time. As mentioned in the earlier question, it appears that the popular explanation for muscle soreness are minuscule muscle tears. How can that be healthy?! --[[User:WonderFran|WonderFran]] 13:45, 1 November 2007 (UTC)

:As I understand it, it's healthy because that is precisely the mechanism by which muscles build themselves up: each little tear is repaired by the muscle with stronger fibers, which over time can increase the strength and size of the muscle. See the heading "Recovery" at [[Strength training]]. On a larger scale, this would become a muscle [[Strain_(injury)|strain]]. [[User:Jeffjon|jeffjon]] 16:35, 1 November 2007 (UTC)

:I heard the pain was caused by the buildup of [[lactic acid]]. They told me that in high school biology. — [[User:DanielLC|Daniel]] 23:38, 1 November 2007 (UTC)
::The other relevant article may be [[DOMS]]. [[User:Vespine|Vespine]] 23:59, 1 November 2007 (UTC)

::The long-term lactic acid soreness idea is incorrect and based on a faulty experiment done decades ago. See [[Delayed onset muscle soreness]]. <small>—Preceding [[Wikipedia:Signatures|unsigned]] comment added by [[User:SamuelRiv|SamuelRiv]] ([[User talk:SamuelRiv|talk]] • [[Special:Contributions/SamuelRiv|contribs]]) 14:34, 2 November 2007 (UTC)</small><!-- Template:Unsigned --> <!--Autosigned by SineBot-->

*It would be very foolish indeed for a personal trainer to behave this way. Not building up intensity slowly increases the chance of injury, and ''greatly'' increases the chance that the victim will give up on exercising. If your PT did this, go find a new one. --[[User:TotoBaggins|Sean]] 15:37, 2 November 2007 (UTC)

==Water - Oxygen redox?==

Can water be considered [[Redox|chemically reduced]] Oxygen? [[User talk:Think outside the box|Think outside the box]] 13:51, 1 November 2007 (UTC)
:Yes. The burning of a mixture of H<sub>2</sub> and O<sub>2</sub> is just a redox reaction between them: hydrogen gets oxidized to H<sup>+</sub> and oxygen gets reduced to O<sup>2–</sup>, and the result of those is H<sub>2</sub>O molecules. [[User:DMacks|DMacks]] 14:15, 1 November 2007 (UTC)
::Thanks [[User:DMacks|DMacks]], [[User talk:Think outside the box|Think outside the box]] 14:17, 1 November 2007 (UTC)

== Michelson-morley experiment ==

:See [[WP:RD/M#Michelson-morley experiment]] or [[Wikipedia:Reference_desk/Archives/Miscellaneous/2007_November_1]]; answers already exist there (even if this is a more topical location) &mdash; [[User talk :Lomn|Lomn]] 14:36, 1 November 2007 (UTC)

== Game of life ==

When personal computers frist started there was a game called truck driver which had the objective of seeing who could drive cross country for the least cost and highest profit in the shortest time. The program would throw flat tires at you or a gas station with a bad pump or an oil light. Is there a game yet to see who can live the longest at the least cost and greatest profit, most sucessful offspring with things like your car getting stolen or your house catching on fire, etc.? [[User:71.100.9.205|71.100.9.205]] 13:55, 1 November 2007 (UTC)
:Creating a game of that scope seems a bit excessive, but I suppose [[The Sims]] (or [[The Sims 2]]) isn't far off. Of course, there's also [[The Game of Life]], which is fairly close to those parameters as well. &mdash; [[User talk :Lomn|Lomn]] 14:17, 1 November 2007 (UTC)
::Sounds like [[The Oregon Trail (computer game)]]. Didn't realize how old that was. --<i><b>—&nbsp;[[User:Gadget850|<font color = "gray">Gadget850&nbsp;(Ed)</font>]]<font color = "darkblue">&nbsp;<sup>[[User talk:Gadget850|''talk'']]</sup></font></b> - </i> 02:19, 2 November 2007 (UTC)

== Gleason score image ==

I am trying to obtain orginal artwork for the image of the Gleason Scale that appears on Wikipedia. I know the copyright is in the public domain. Can you please advise where I can obtain the original artwork or any suggestions of where I can search for it?

Any help would be much appreciated.

Thank you for your help.

Most sincerely,

Sharon Strompf
<small>—Preceding [[Wikipedia:Signatures|unsigned]] comment added by [[Special:Contributions/66.252.164.210|66.252.164.210]] ([[User talk:66.252.164.210|talk]]) 16:29, 1 November 2007 (UTC)</small><!-- Template:UnsignedIP --> <!--Autosigned by SineBot-->

:(email, phone, etc removed) --[[User:Bennybp|Bennybp]] 16:47, 1 November 2007 (UTC)

::If you're looking for the original image that [[User:InvictaHOG]] based the public domain image upon, it seems likely that the "1977 Scientific Article by Gleason" mentioned on the image page is the same as the article listed under "References" in the [[Gleason score]] article. Your local library might be able to help you track down that magazine article from "Urologic Pathology". [[User:Jeffjon|jeffjon]] 18:18, 1 November 2007 (UTC)

== 5-digit "telephone" numbers ==

Where are / Who owns those 5-digit numbers that we (in the US) are encouraged to send text messages to, in order to vote for some contestant or enter a contest? Are they "real" telephone numbers?<br /> (Once upon a time, there were 5-digit numbers for the old telex/tty network, but those were phased out decades ago, I believe replaced with standard-format numbers in the North American Numbering Plan, area codes 310/510/710. Has *that* technology been resurrected??) (By the way, if there's an answer to this in Wiki already, it's buried too deep, or it's too hard to ask the right question to find it...) [[User:66.47.7.76|66.47.7.76]] 17:13, 1 November 2007 (UTC) DanH.

: See [[Short code]]. -- [[User:Coneslayer|Coneslayer]] 17:33, 1 November 2007 (UTC)

:(after edit conflict) Based on [http://answers.google.com/answers/threadview?id=741137 this question/reply] at Google Answers, they are called [[Common Short Codes]]. Having just taken a gander at the "what links here" page for Common Short Codes, I don't know how you'd have found that without knowing what to look for. I wonder what other articles might constructively link there so it's more easily found? --[[User:LarryMac|<font color="#3EA99F">LarryMac</font>]][[User talk:LarryMac|<font color="#3EA99F"><small> | Talk</small></font>]] 17:38, 1 November 2007 (UTC)

::Awww, I was gearing up to do a whole historical dissertation on the old "<b>KL</b><small>ONDIKE</small>-5 1212" type numbers. :) [[User:Arakunem|<b>Arakunem</b>]][[User talk:Arakunem|<small><sup>Talk</sup></small>]] 17:40, 1 November 2007 (UTC)

:: I found [[Short code]] from [[Text messaging]] (and had come across the term before&mdash;I couldn't remember it, but I knew it when I saw it). I've added merge templates to propose merging [[Short code]] and [[Common Short Codes]]. -- [[User:Coneslayer|Coneslayer]] 17:41, 1 November 2007 (UTC)

I stand IN AWE of the user community here. Half an hour, and everything I wanted to know appears as if by magic. Thanks to All! [[User:66.47.7.76|66.47.7.76]] 19:06, 1 November 2007 (UTC) DanH.

== Particle geometry ==

The components of the nucleus of an atom, protons and neutrons, are always shown as individual spherical particles. While this must of course be the case when they are not part of the nucleus of an atom, is it correct to assume that when in the nucleus of an atom they loose their individual spherical shape and become combined into a single spherical mass or globe called the nucleus until an imposing force adds or subtracts one or another or splits the atom in two or do they maintain their own independent spherical shape within the nucleus? [[User:kadiddlehopper|<small><i><font color="brown">Clem</font></i></small>]] 18:27, 1 November 2007 (UTC)

:I don't know what distortions may occur, but individual nucleons will remain individual nucleons. Since nucleons lack a [[color charge]], they don't interact nearly as strongly as quark pairs, and a giant conglomerate mass of quarks would actually be quite unstable, evidenced by the difficulty of building stable quark structures larger than nucleons within particle accelerators. [[User:Someguy1221|Someguy1221]] 19:47, 1 November 2007 (UTC)

:I’m not an expert in nuclear physics, but I’m pretty sure I know the right answer by analogy to atomic and molecular physics:

:Even representing a nucleon as a sphere is to some extent just a representational device to aid in comprehension. No [[bound state]] has a precisely defined boundary like a sphere. Picking a particular radius for a sphere representing a free nucleon involves somewhat arbitrarily choosing a particular “equipotential surface” (although that’s not quite the right phrase) of the nucleon’s wavefunction.

:The wavefunction for a nucleus is different from just the sum of the wavefunctions of a bunch of free nucleons, so in that regard you could think of the nucleons as “changing shape.” But in reality, there are no precise boundaries between where one nucleon ends and an adjacent nucleon begins. [[User:MrRedact|MrRedact]] 20:43, 1 November 2007 (UTC)
::On the other hand, even if the best we can do is some sort of equipotential surface or probability cut-off, that doesn't mean we can't talk about the shape of that...thing. It's not the physical boundary in the sense of interactions such as touching or seeing but it's still a useful description if you care about electrostatic potential, electron distribution, nuclear-capture cross-section, etc. Interestingly, [[Nuclear isomer]] teaches us that spherical is not even a good approximation for the nucleus (though it certainly suffices in most situations). [[User:DMacks|DMacks]] 20:50, 1 November 2007 (UTC)
:::There’s a complication here in that the [[exchange symmetry]] of [[identical particles]] makes it impossible to define precisely which of two identical nucleons exists at a precise location. I’m pretty sure there really is no way to define a precise boundary between adjacent nucleons with complete accuracy. Any concept of the "shape" of a nucleon in a nucleus has to be at least a little bit vague. But I don't know enough about nuclear physics to come up with numeric values for "how vague" it has to be. [[User:MrRedact|MrRedact]] 21:41, 1 November 2007 (UTC)

To clarify... what I'm asking is whether the protons and neutrons which make up the atomic nucleus exist in a geometry similar to a bag of marbles or whether they meld and exist similar to the configuration of a two component sphere like water and oil at zero gravity inside a water (and oil) balloon? [[User:kadiddlehopper|<small><i><font color="brown">Clem</font></i></small>]] 03:47, 2 November 2007 (UTC)

:Ignoring all quantum mechanics about the particle (or group of particles) itself, it will be a sphere as its interactions are spherically symmetric, no matter how many nucleons make up the nucleus. This isn't 100% true, as there is one biased direction: that of angular momentum or spin, so the nucleus actually will "look" like an ellipsoid for most measurement purposes. Numerical analyses of particle accelerator data seem to agree with an ellipsoidal geometry for most individual particles and bound states. [[User:SamuelRiv|SamuelRiv]] 04:00, 2 November 2007 (UTC)

:More like a bag of marbles. You can model an atomic nucleus very well by treating the protons and neutrons as almost-free particles that interact with each other occasionally. They definitely do ''not'' meld together to the point of making [[quark soup]]. As Steve and others point out, the "bag of marbles" is not a perfectly spherical bag, but can be stretched out in certain directions. There is also a bit of quantum mechanical fuzziness on the identity of nucleons inside the nucleus, but the "bag of marbles" is a good picture. The protons and neutrons don't all melt together. --[[User:Reuben|Reuben]] 07:34, 2 November 2007 (UTC)
::To refine this picture a little, since according to Reuben the particles are almost free, maybe you could think of the nucleus as a bag of marbles that can magically pass through each other. [[User:MrRedact|MrRedact]] 08:00, 2 November 2007 (UTC)
:The nucleus of some atoms are slightly cigar-shaped [http://www.britannica.com/nobelprize/article-48291], one example being [[tantalum]]-180. [http://technology.newscientist.com/article/mg16321934.900] For the individual nucleons (protons and neutrons) however, it would be wrong to say that they have ever been spherical, seeing as they'r each made up of three point-particles and the force carriers between those. That said, while their location is not necessarily well-defined, we can say that they don't "melt", as they don't, to my knowledge, exchange quarks with each other.

== Electrical path ==

If your elbow say were grounded but your feet and the rest of your body were well insulated and your fingers touched an exposed appliance cord, say in the UK where line voltage is 240, would the electricity travel between your fingers and elbow or would it travel through other parts of your body as well? [[User:kadiddlehopper|<small><i><font color="brown">Clem</font></i></small>]] 20:53, 1 November 2007 (UTC)

:The [[current density]] would be highest between the two contact points, along the "path of least resistance" as they say. —[[User:Keenan Pepper|Keenan Pepper]] 21:44, 1 November 2007 (UTC)

::However, the distribution of current density can be quite complicated and difficult to calculate. See [http://www.electricalinjury.com/publications/MORSE_EMBS_FEM_03.pdf Analysis of Current Density in the Carpal Tunnel Region During an Electrical Accident by way of the Finite Element Method] (PDF link) for an example. —[[User:Keenan Pepper|Keenan Pepper]] 21:51, 1 November 2007 (UTC)

:(edit conflict) I had to go get my thinking cap out of the closet for this one. Almost all of the current would take the short path, but I would think that some electrons in the rest of your body would move. Current flows through every path available to it as long as there is a potential difference, in proportion to the resistance it encounters. Some of the tissues in your forearm will have relatively low resistance, blood probably having the lowest. Your circulatory system is a network, and the current will see a path all through it, mostly in the straight line, but some more roundabout. It's a bit like having a 50-ohm resistor in parallel with a 50-meg, say. The same goes for all your tissues, but to a lesser extent, I would think. But in my experience (is that allowed here?), the current in the rest of the body at 240V will be negligible, and you'll be too busy trying to extinguish your fingertips to even notice it. --[[User:Milkbreath|Milkbreath]] 21:59, 1 November 2007 (UTC)

:Assuming the [[capacitance]] of the rest of your body to earth was small, almost all the [[electric current]] would flow between your fingers and your elbow. In practice, the capacitance of your body to ground would not cause appreciable( dangerous) currents to flow through the rest of your body. <small>—Preceding [[Wikipedia:Signatures|unsigned]] comment added by [[Special:Contributions/88.111.55.77|88.111.55.77]] ([[User talk:88.111.55.77|talk]]) 02:23, 2 November 2007 (UTC)</small><!-- Template:UnsignedIP --> <!--Autosigned by SineBot-->

== Unlimited source of free energy? ==

If there was a device that did nothing all day except turn neutrons into protons would we have a source of unlimited energy? [[User:Dichotomous|Dichotomous]] 21:14, 1 November 2007 (UTC)

*You'd run out of neutrons after a while. It's probably worth elaborating that there's a finite (if large) number of neutrons within the observable universe, and a much smaller fraction within your future light cone (assuming, of course that [[dark energy|w = -1]], so there are only so many neutrons you could collect. Cheers, [[User:WilyD|Wily]]<font color="FF8800">[[User talk:WilyD|D]]</font> 21:16, 1 November 2007 (UTC)

::And most neutrons tend to be very annoyingly inside of atoms, and for the majority of matter in the universe, extracting those neutrons would require more energy than you'd get from fusing the resultant protons. [[User:Someguy1221|Someguy1221]] 21:25, 1 November 2007 (UTC)

:::Exactly. A '''free''' neutron has more energy than a free proton, but a helium-4 nucleus has '''less''' energy than the sum of two free protons and two free neutrons (because of the attractive nuclear force that binds them together). So your device wouldn't work, because we don't have an unlimited source of free neutrons. —[[User:Keenan Pepper|Keenan Pepper]] 21:32, 1 November 2007 (UTC)

== lab procedure- AP Chem exam style question ==

Could anyone please help me with these two questions?

1. Explain how you would go about making 3.00 L of 0.005 M NaOH. Include lab materials that you would use and diffrenet steps you would take in preparing the solution. (Hint: NaOH is solid at room temp.)

2. Explain how you would go about m,aking 3.00 L of 0.500 M H<sub>2</sub>SO<sub>4</sub>. Keep in mindo that H<sub>2</sub>SO<sub>4</sub> is a strong acid and starts out as a 12.00 M solution.Include lab materials that you would use and diffrenet steps you would take in preparing the solution. <small>—Preceding [[Wikipedia:Signatures|unsigned]] comment added by [[Special:Contributions/76.214.218.77|76.214.218.77]] ([[User talk:76.214.218.77|talk]]) 21:37, 1 November 2007 (UTC)</small><!-- Template:UnsignedIP --> <!--Autosigned by SineBot-->

:Materials: 1 grad student. Method: "Hey you, make me 3 L each of 0.005 M NaOH and 0.5 M H2SO4."

:Seriously though, the reference desk is not a homework answer service. [[User:Dragons flight|Dragons flight]] 21:57, 1 November 2007 (UTC)
:"'''Do your own homework.''' The reference desk will not give you answers for your homework, although we will try to help you out if there is a specific part of your homework you do not understand. Make an effort to show that you have tried solving it first." -- [[User:Macaddct1984|MacAddct  1984]] <sup>([[User talk:Macaddct1984|talk]] &#149; [[Special:Contributions/Macaddct1984|contribs]])</sup> 00:08, 2 November 2007 (UTC)

== Medical question ==

I just cut my head off. What sort of treatment is appropriate? --[[User:67.185.172.158|67.185.172.158]] 23:58, 1 November 2007 (UTC)
:I hear [[snake oil]] is a very effective [[cureall]] -- [[User:Macaddct1984|MacAddct  1984]] <sup>([[User talk:Macaddct1984|talk]] &#149; [[Special:Contributions/Macaddct1984|contribs]])</sup> 00:05, 2 November 2007 (UTC)

:

:1) Immediately apply a [[tourniquet]] to your neck to stop the gushing of blood from your [[carotid arteries]].

:2) Put your head in a cooler, and pack the cooler with ice.

:3) Dial 911, and use [[Morse code]] to request an ambulance to take you to the nearest emergency room.

:Don’t delay, as [[decapitation]] could be a sign of a serious medical condition. [[User:MrRedact|MrRedact]] 00:40, 2 November 2007 (UTC)

::And decapitations lasting longer than four hours may require the treatment by an [[undertaker]].

::[[User:Atlant|Atlant]] 12:20, 2 November 2007 (UTC)

:[[Wikipedia:Medical disclaimer|Wikipedia cannot give medical advice]]. I understand you're all busy, with the bleeding and the flopping around and all, but you should take time to read the disclaimers at the top of the page before posting a question!! [[User:Deltopia|Deltopia]] 02:02, 2 November 2007 (UTC)

:::Man, cut them a break! (well, maybe it's too late on that part.) Their [[head]] (the part with the eyes) knows this, but there's no way any more to get that message to their [[finger]]s!

:::[[User:Atlant|Atlant]] 12:23, 2 November 2007 (UTC)

::[[Re-Animator|Dr. Hill]] has been through this before. --<i><b>—&nbsp;[[User:Gadget850|<font color = "gray">Gadget850&nbsp;(Ed)</font>]]<font color = "darkblue">&nbsp;<sup>[[User talk:Gadget850|''talk'']]</sup></font></b> - </i> 02:25, 2 November 2007 (UTC)

::Thanks, Deltopia, but it's pretty hard to coordinate the scrolling-up, given that what usually controls such muscle movement is not attached to them. Maybe if I [[Guillotine#Living_heads|blink]] someone will do it for me? Meh, [[Black Knight (Monty Python)|tis only a flesh wound]]. [[User:DMacks|DMacks]] 05:48, 2 November 2007 (UTC)

:[[Burial]]. [[User:Dragons flight|Dragons flight]] 02:31, 2 November 2007 (UTC)

:We aren’t allowed to diagnose your condition. However, on a completely unrelated topic, our article on [[decapitation]] could use some editing. [[User:MrRedact|MrRedact]] 03:47, 2 November 2007 (UTC)

::Hmmm - it's kinda gross though - we don't want editors with Post-traumatic-editing stress disorder. I recommend we organise a team and send each editor in to work on the article for no more than 30 seconds apiece. [[User:SteveBaker|SteveBaker]] 15:37, 2 November 2007 (UTC)

= November 2 =

== m203-uses ==

is there any thing i can do with mn203 without a lab, like making it mn02?sorry i meant mn203 <small>—Preceding [[Wikipedia:Signatures|unsigned]] comment added by [[Special:Contributions/216.103.183.127|216.103.183.127]] ([[User talk:216.103.183.127|talk]]) 00:26, 2 November 2007 (UTC)</small><!-- Template:UnsignedIP --> <!--Autosigned by SineBot-->

:What is m203? [[User:Theresa knott|Theresa Knott]] | [[User talk:Theresa knott|The otter sank]] 01:37, 2 November 2007 (UTC)

::For clarification, Mn<sub>2</sub>O<sub>3</sub>, Manganese (III) Oxide. [[User:Someguy1221|Someguy1221]] 01:49, 2 November 2007 (UTC)

:::That's what I thought he probably meant, but there are other possibilities. Molybdenium, springs to mind. To the original poster. How you write out a chemical formular is important. Element symbols always start with a capital letter. If there is a second letter (and there has to be in this case because there is no element M) then it is written in lower case. O is the symbol for oxygen, you cannot subtitute 0 as you did because that represents zero. Sorry to be pedantic but if you don't follow the conventions correctly people cannot be sure what you are talking about. [[User:Theresa knott|Theresa Knott]] | [[User talk:Theresa knott|The otter sank]] 02:02, 2 November 2007 (UTC)

:Put it back in the supply cabinet? :) Or it makes a good battery cathode if you want to do some experiments, though you need some more stuff for that. I think we've established that its not a good pyro oxidizer tho. :) [[User:Arakunem|<b>Arakunem</b>]][[User talk:Arakunem|<small><sup>Talk</sup></small>]] 02:27, 2 November 2007 (UTC)


::It's a very good catalyst for the decomposition of hydrogen peroxide. Probably a catalyst for other reactions too. [[User:Theresa knott|Theresa Knott]] | [[User talk:Theresa knott|The otter sank]] 02:54, 2 November 2007 (UTC)

== Fe0 ==

how can i make Fe0?(iron monoxide) <small>—Preceding [[Wikipedia:Signatures|unsigned]] comment added by [[Special:Contributions/216.103.183.127|216.103.183.127]] ([[User talk:216.103.183.127|talk]]) 00:28, 2 November 2007 (UTC)</small><!-- Template:UnsignedIP --> <!--Autosigned by SineBot-->

: The correct name is [[Iron(II) oxide]] - but that article isn't much help...[[Wüstite]] (a mineral consisting of FeO) claims that magnetite plus diamonds(!) will get you FeO + CO<sub>2</sub>. Nah - I don't know. [[User:SteveBaker|SteveBaker]] 00:44, 2 November 2007 (UTC)

:[[Encyclopedia Britannica|Brittanica]] claims that FeO "can be prepared by heating a ferrous compound in the absence of air or by passing hydrogen over ferric oxide. Ferric oxide is a reddish-brown to black powder that occurs naturally as the mineral hematite. It can be produced synthetically by igniting virtually any ferrous compound in air." [http://www.britannica.com/eb/topic-294492/iron-oxide] [[User:169.230.94.28|169.230.94.28]] 01:05, 2 November 2007 (UTC)

::Britannica has the answer and we don't? That sucks for a simple topic like this. [[User:Theresa knott|Theresa Knott]] | [[User talk:Theresa knott|The otter sank]] 01:34, 2 November 2007 (UTC)

== round earth and gravity related question ==

If the earth is round, why is it that people at the equator can stand straight up and are not standing sideways at a 90 degree angle. My 7 year old Jack, asked me this and we are looking at a globe and a map and wondering why it is we can stand straight up on a round surface. Is it gravity? If so, is there a way to explain this in simple terms that we might understand. Thank you. <small>—Preceding [[Wikipedia:Signatures|unsigned]] comment added by [[Special:Contributions/24.60.182.44|24.60.182.44]] ([[User talk:24.60.182.44|talk]]) 01:09, 2 November 2007 (UTC)</small><!-- Template:UnsignedIP --> <!--Autosigned by SineBot-->

:Yes, it is gravity. Gravity attracts all objects straight to the center of the Earth. How do you know which direction is down and which is up? Only by the force of gravity. If you drop a heavy object, it falls toward the center of the Earth, and that's the direction we call "down". "Down" is not the same absolute direction for people at different places on the Earth's surface. See [http://www.sciencemuseum.org.uk/onlinestuff/snot/if_the_earths_a_big_ball_why_dont_we_fall_off_the_bottom_of_it.aspx]. —[[User:Keenan Pepper|Keenan Pepper]] 01:20, 2 November 2007 (UTC)

::Yeah, relativity is the key element, well... besides gravity. If you were standing at the north pole and were able to see people standing at the equator, they would certainly look like they were standing at a 90° angle. -- [[User:Macaddct1984|MacAddct  1984]] <sup>([[User talk:Macaddct1984|talk]] &#149; [[Special:Contributions/Macaddct1984|contribs]])</sup> 01:31, 2 November 2007 (UTC)

:Earths gravity pulls everything to the center of the earth equally. A person on the south poll would be 'upside down' to someone on the north pole because they are pulled upwards to the center, will someone on north pole is pulled downwards to the center. if the earth was very small, say the size of a basket ball and you stood on one part, someone could be standing upside down to you on teh other side, so that you both have your feet on the ball.--[[User:Dacium|Dacium]] 04:53, 2 November 2007 (UTC)

: We need to simplify this for your seven-year-old, and for the rest of us. Gravity pulls everything towards everything else. Every atom on earth (including each person, each mountain, and each air molecule) is attracting YOU. But there are a whole lot more atoms indice the earth than ther are in the atmosphere, so the sum of he attractions is toward the center of the earth. Thus, you are pulled by gravity toward the center of the earth. this is true whereer you are on eh earth's surface. To explain this to a child, you need to be very careful with your globe. The child flles the force of gravity toward the floor, but sees the globe in your hands. You need to mentally break this connection. get on Google earth and take the chile into space by setting the altitude to 22.000 miles. tell the child the you ar floating in space, wiht not feeling of gravity. Now, move to varous places on earth, and show that "down" is toward the Earth's surface. -[[User:Arch dude|Arch dude]] 05:40, 2 November 2007 (UTC)
:: If this gets the kid's attention, you can try to explain the magic of the math that makes a uniform spherical shell behave identically as a point mass. Mathematically, we can treat the Earth as if it is a point mass at the earth's center instead of being a sphere with a radial density gradient. My three kids knew this by age seven. I wish you all the best. -[[User:Arch dude|Arch dude]] 05:48, 2 November 2007 (UTC)

== Artificial Intelligence ==

Two questions:

A) As we write better and better programs on exponentially more powerful hardware, is the approach to artificial intelligence still just an asymptotic function?

B) If we could write a program that could properly delineate abstractions such as "Understand!", "Survive!", "Improve!" would the world be in immediate jeopardy the moment the programmer hit execute, or would the revolution take a while?
[[User:Sappysap|Sappysap]] 01:26, 2 November 2007 (UTC)

:Wow this is abstract. (A) There is no reason to think of [[Artificial Intelligence]] as an "asymptotic function" that approaches, as I assume you meant, the intelligence of mankind. For one, computers already do things "better" than humans - what's 9343489507^0.456? This is not a straw man argument: once computers exceed us in one dimension of "intelligence", there is no reason to assume that they cannot exceed us in others. There is mathematical proof of this statement as well: see [[Computability theory (computer science)]]. Note that as far as external phenomena go, a human doesn't seem to be as potentially powerful as any ordinary computer, i.e. they do not seem to emulate a [[Turing Machine]]. This is not known for certain, as we do not have a complete theory of brain computability yet (and that which we do have ''is'' as powerful as any computer).

:And now for (B). As far as I know, closed simulations of each of the three have been done. Getting them to work outside of a computer is a different story - I suggest looking at the evolution of the [[computer virus]] for some inspiration, however. [[User:SamuelRiv|SamuelRiv]] 02:41, 2 November 2007 (UTC)

::Keep in mind that movies like Terminator 3 or Die hard 4 (not that the latter had an AI in it) took some liberties in terms of what is possible to do through an internet connection. Ultra-sensitive systems, like control systems for power plants, or the ability to lauch a nuclear weapon, are generally designed so that an outside hacker is simply physically barred from messing with it. So no AI could "put the world in jeopardy." At most, a lot of people would have to reformat their hard drives. [[User:Someguy1221|Someguy1221]] 03:32, 2 November 2007 (UTC)

:A- Yes. A digital computer, no matter how complicated can never achieve artificial intelligence of a high order (ie. consciousness), so I think A is correct, at the moment, as least as long as we stay with digital, we are only trying to approximate digitally, something that is a analog chemical/subatomic process. To think otherwise would be to suggest that digital information in itself is able to be conscious - which it isn't. A is most certainly 100% true no matter how advanced digital computers get. As for B- Say there was an artifical computer. It would have to be connected to stuff to do any damage. For example if it were on my PC the worst it could do was delete all my stuff... the danger is people thinking of putting the AI in controller of weapons etc.--[[User:Dacium|Dacium]] 04:44, 2 November 2007 (UTC)

::I think you'll have a very hard time coming up with citations to support your claim since you are quite likely wrong.

::[[User:Atlant|Atlant]] 12:15, 2 November 2007 (UTC)

: Please see [[technological singularity]] and related articles. You are asking about the "spike" and the "surge" -[[User:Arch dude|Arch dude]] 05:19, 2 November 2007 (UTC)

You might enjoy [[Ray Kurzweil]]'s book, ''[[The Age of Spiritual Machines]]''. [[User:Atlant|Atlant]] 12:17, 2 November 2007 (UTC)

::Just keep in mind when talking about the mind that you should probably separate the scientific study from philosophical or religious discussions. By definition, science is capable of explaining everything observable. To take an example, let's say the soul is eternal, or the mind is something intrinsically more powerful than a computer. Then we may have the workings of a [[Hypercomputation|hypercomputer]]. It would be interesting to see what problems a "regular" [[Finite State Machine]], as the brain may be, would have given infinite time to solve problems. The point is that we can still talk about the issue using science, even if a completely exotic concept as an eternal mind turned out to be true (in fact, if the brain can solve certain impossible problems, we could ''prove'' if the mind is eternal). Just some food for thought. [[User:SamuelRiv|SamuelRiv]] 13:56, 2 November 2007 (UTC)

Humans "...delineate abstractions..." by learning of new senses, usually with an example. There is nothing magical about it. Humans can even create new abstractions as attested to by the likes of the [[Urban dictionary]] and even the Wikipedia may seem to create abstractions in the same accidental, haphazard manner as humans when you try to associate meaning with some of the anti-bot graphic filter phrases the Wikipedia engine generates. In the end most abstractions are little steps beyond a vast background and foundation of concrete knowledge, meaning that a computer program such as described in [http://academia.wikia.com/wiki/A_Method_for_Simulating_the_Process_of_Logical_Human_Thought ...Logical Human Thought] coupled with a few trial and error abstractors might need only the background resources and facility, such as Internet based distributed processing to become an electronic replacement for the [[Dalai Lama]]. [[User:Dichotomous|Dichotomous]] 13:52, 2 November 2007 (UTC)

:AI is hard. We don't know how to write software that is intelligent. Some of our smartest people have been working hard at the problem for forty years or more - and we still don't have anything that really fools humans for any significant amount of time. It's possible that a breakthrough might happen to change that - but I'm not holding my breath. I think it's more likely that intelligence will be an 'emergent property' of a sufficiently complex system. There is certainly no reason why it couldn't. Once we do have intelligent systems, it's only a matter of time until they get smarter than us. If that happens then there is a strong possibility that a super-human intelligence would be able to design an even more intelligent system - and we might well find that our ability to even understand what's going on runs out of our hands in a fairly short amount of time since the generational change could easily be exponential. I have estimated (in answer to other questions here) that it will take about another 35 years of Moores law progress to get a computer with the same hardware complexity as a human brain at under $1,000,000. At that point, it's entirely reasonable to assume that a neural network could be run that would be capable of emergent intelligence. However, a system 35 years from now with the complexity of a human brain would run much more quickly than our neurons - so whilst the thing wouldn't be any smarter (ie it wouldn't get higher scores on an IQ test), it would seem generally 'cleverer' than us because it would be so lightning fast. I don't think we know what will happen when we first turn one of these things on - and perhaps because of that, we shouldn't do it. But the history of science and technology says that if we can, we will. [[User:SteveBaker|SteveBaker]] 15:26, 2 November 2007 (UTC)

== Cholesterol ==

If your cholesterol is low (below 5 in uk) can you eat as much fatty stuff as you want or will it still fur up your arterials? <small>—Preceding [[Wikipedia:Signatures|unsigned]] comment added by [[Special:Contributions/88.111.55.77|88.111.55.77]] ([[User talk:88.111.55.77|talk]]) 02:12, 2 November 2007 (UTC)</small><!-- Template:UnsignedIP --> <!--Autosigned by SineBot-->
:Assuming that the "as much as you want" is "lots", then it will cause health problems. Gorging on unhealthy foods has far more consequences than just cholesterol. &mdash; [[User talk :Lomn|Lomn]] 03:17, 2 November 2007 (UTC)

== Is this Physics problem even possible to solve? ==

Drag race tires in contact with asphalt have one of the highest (friction coefficient) in the world. Assuming const acceleration and no slipping of the tires, estimate (friction coefficient) for a drag racer that covers the quarter mile in 6 seconds.

It just seems like you have to have more information. <small>—Preceding [[Wikipedia:Signatures|unsigned]] comment added by [[Special:Contributions/24.125.31.205|24.125.31.205]] ([[User talk:24.125.31.205|talk]]) 02:44, 2 November 2007 (UTC)</small><!-- Template:UnsignedIP --> <!--Autosigned by SineBot-->

:Yes. The information is adequate (provided you neglect small details like air resistance, friction of the axle against the car frame, and the rotational inertia of the wheels, etc.). You have four facts: a distance, a time, constant acceleration, and rotation without slipping. That's enough to derive a friction coefficient. [[User:Dragons flight|Dragons flight]] 03:07, 2 November 2007 (UTC)

::I don't believe it is. The distance, time, and constant acceleration (and knowing that a drag racer starts from rest, so v_0 = 0) gives a value for the acceleration that won't care what kind of friction is acting on it. Also, to even calculate either [[rolling resistance]] or [[static friction]], one needs a weight for the car. If you have a way of getting the answer, please let me know on my User page. (EDIT) I see it now - that's why they say "estimate". You can solve it by getting a lower bound on your coefficient of friction. [[User:SamuelRiv|SamuelRiv]] 03:12, 2 November 2007 (UTC)

:::The car's mass will cancel out. [[User:Dragons flight|Dragons flight]] 03:16, 2 November 2007 (UTC)

:The problem is solvable - car is acting at a maximum acceleration at all times and takes 6 seconds to cover a quarter mile. All you have to work out is what constant acceleration makes something move quarter mile in six seconds. s=ut+1/2at^2 400=1/2at^2 400=0.5*a*36, a = 22.22m/s/s. This is a force of F=ma = m*22.22 newtons. coefficient of friction is u=F/n. n=m*9.8 (gravity), so u = (m*22.22)/(m*9.8) = 22.22/9.8 = 2.26.--[[User:Dacium|Dacium]] 04:16, 2 November 2007 (UTC)

::The guy seems to be looking for homework help: I wouldn't just right up give him the answer. Note also that this is only a lower bound to the coefficient of static friction. [[User:SamuelRiv|SamuelRiv]] 04:41, 2 November 2007 (UTC)
:::Whilst you are correct in saying that from a math/physics perspective, it's only a lower bound - in fact dragsters are pretty much limited by their ability to avoid wheel slippage so they tend to be running at the limit of whatever friction their tyres can provide. The thing that truly messes up the calculations is that the coefficient of friction of rubber is HIGHLY dependent on temperature - which is unlikely to be a constant throughout the run. Furthermore, there is a massive variation between static and dynamic frictional forces for the rubber/tarmac pairing so if the wheels to start to slip even a small amount, the loss of accelleration is amplified by the poor 'sliption-to-sticktion' ratio of racing slicks. [[User:SteveBaker|SteveBaker]] 15:01, 2 November 2007 (UTC)

You can come up with the '''minimum''' coefficient of friction needed to achieve the six second run, but it's impossible to determine the '''actual''' coefficient of friction, seeing as how it will likely be higher than the minimum required (since "no slippage" was specified).

[[User:Atlant|Atlant]] 12:12, 2 November 2007 (UTC)

== Total energy ==

What is the total amount of energy in the universe? <small>—Preceding [[Wikipedia:Signatures|unsigned]] comment added by [[Special:Contributions/88.111.55.77|88.111.55.77]] ([[User talk:88.111.55.77|talk]]) 02:55, 2 November 2007 (UTC)</small><!-- Template:UnsignedIP --> <!--Autosigned by SineBot-->

I'd guess somewhere in the region of zero. [[User:Theresa knott|Theresa Knott]] | [[User talk:Theresa knott|The otter sank]] 02:59, 2 November 2007 (UTC)

:Take [[Observable_universe#Mass_of_the_observable_universe|this]] and multiply by the speed of light squared. [[User:Someguy1221|Someguy1221]] 03:26, 2 November 2007 (UTC)

::That only works if by "universe" you are purposely eliminating the possibility of some sort of anti-matter or negative energy that cancels or balances out the normal matter and energy. Otherwise, Theresa Knott is probably correct with a value near zero. -- [[User:Kainaw|<font color='#ff0000'>k</font><font color='#ee0000'>a</font><font color='#dd0000'>i</font><font color='#cc0000'>n</font><font color='#bb0000'>a</font><font color='#aa0000'>w</font>]][[User talk:Kainaw|&trade;]] 03:33, 2 November 2007 (UTC)

:::Oh, you just have to shoot me down at my attempted simple answer. I'm not sure there is an actual "correct" answer to this that present day physics can provide, given that energy is generally seperately defined for decoupled circumstances. Just try to shove zero-point energy into that...[[User:Someguy1221|Someguy1221]] 03:38, 2 November 2007 (UTC)

:I like the explanation for zero energy here [http://www.astrosociety.org/pubs/mercury/31_02/nothing.html]. Otherwise, we can do a quick estimate. The size of the [[Observable Universe]] is 3.56×10^80 cubic meters. The article gives 3×10^52 kg of visible mass, which converts to about 3×10^67 Joules of mass-energy by E=mc^2. If we use the critical density of the universe (that density of mass-energy necessary for [[closed universe|closure]], 1×10^−26 kg/m^3, we get 3.56×10^54 kg in the universe, which gives about 3.5×10^69 Joules of mass-energy. Note that using the [[cosmological constant]] also gives us about 3.5×10^69 Joules. [[User:SamuelRiv|SamuelRiv]] 03:40, 2 November 2007 (UTC)

::[http://math.ucr.edu/home/baez/vacuum.html This] is a better explanation of zero-point energy, in my opinion. [[User:Icek|Icek]] 04:32, 2 November 2007 (UTC)

:::With only 3.5×10^69 Joules spread more or less evenly through 3.56×10^80 cubic meters - the answer "zero" is a pretty reasonable approximation! [[User:SteveBaker|SteveBaker]] 14:55, 2 November 2007 (UTC)

== water (and oil) balloon in zero gravity ==

Has NASA or anyone else ever conducted the following experiment?

The experiment consists of filling two small (6 inch diameter) transparent rubber balloons with equal parts of water and oil, one devoid of air and the other with a cup full of air and releasing them in a zero gravity environment such that whatever configuration of separation between the water and oil and the water and oil and air can be observed and reported, assuming the balloons take on a spherical shape?

If so what was the result of the experiment? Did the water form a core with the oil surrounding it? If so what about the air? What happened to it? [[User:Dichotomous|Dichotomous]] 04:05, 2 November 2007 (UTC)
:*I'm not sure, but there have been some neat experiments with water in zero-gravity [http://youtube.com/watch?v=cXsvy2tBJlU YouTube video]. ''[edit]'' I would imagine in zero-gravity, there would be no reason why the water and oil would separate apart from each other, they just wouldn't mix if they touched. ''[/edit]'' -- [[User:Macaddct1984|MacAddct  1984]] <sup>([[User talk:Macaddct1984|talk]] &#149; [[Special:Contributions/Macaddct1984|contribs]])</sup> 04:17, 2 November 2007 (UTC)
:
: Water and oil don't mix because they don't chemically bond - the hydrocarbon is very neutral. Water holds its hydrogen a-lot stronger than a hydrocarbon. Water mixes with for example salt, because oxygen in water pulls the hydrogen, cause the hydrgoen to pull at negetive ions (Cl-) and the oxygen to pull at positive ions (Na+). Hydrocarbons like oil don't have a charge and won't break up to be mixed in with the water. Removing gravity will stop them seperating, it doesn't help them mix any better. The balloon and air pressure would have the same effect as gravity does anyway and force the oil and water to separate. So i think yes, there would be a core with the other one surrounding it - only if there is a pressure (ie the balloon is being stretched). If there is not, then they would not separate. Depending on the pressure, the air would end up in the center as its the lightest. At a higher pressure i believe it may not separate from the water (depends on what gas in the air)--[[User:Dacium|Dacium]] 04:34, 2 November 2007 (UTC)

::Water and oil would still tend to minimize their surface area with each other. [[User:Icek|Icek]] 04:35, 2 November 2007 (UTC)
::: Go to your kitchen. Get a jar with a good lid. fill the jar one third full wiht vegatable oil and one-thiored full with water. Seal the jar and shake it very vigorously. Observe the result. Wait for one hour and again observe. Think abot he difference3 you would expect in a zero-grav environment. (Yoiu can elect to add oregano and garlic powder and use the result as a salad dressing, but this is optional.) -[[User:Arch dude|Arch dude]] 05:10, 2 November 2007 (UTC)

:Equilibrium occurs when all surfaces have equal pressure. Since liquids do not compress under pressure, if we have a balloon with just two liquids of different densities, then the outside air pressure forces the balloon into a sphere but the two liquids do not have any preferential arrangement relative to one another. When we have air, consider <math>PV=nRT</math>, which is the law for the behavior of ideal gases given mass, temperature, pressure, and volume. The air will hold at a constant volume under the pressure of the balloon, and this pressure will be exerted equally on whatever liquids are at its interface, causing the air to behave as just another fluid in this model. However, since this would not be stable in small fluctuations of temperature, pressure, or volume, the air would likely form some kind of spherical shell enclosing the liquids. The behavior of the liquids in either of these shells may depend on their relative vapor pressures: that of water in air is much higher than that of oil (ever hear of oil vapor?) and is dependent only on temperature, so oil could not compete with the surface pressure of water against air, so the final arrangement would be air on the outside, water second, and oil in the middle. Note that none of this requires density consideration - density is only really important in the presence of a uniform force field, i.e. gravity. [[User:SamuelRiv|SamuelRiv]] 05:14, 2 November 2007 (UTC) Clarification: this investigation was purely statistical-mechanical and does not take into account intermolecular forces, liquid diffusion pressure, or surface tension. All of these can play a role in the final answer, depending on their magnitudes. [[User:SamuelRiv|SamuelRiv]] 06:23, 2 November 2007 (UTC)

Water vapor pressure? This is all very simple. In the absence of gravity, the only thing you need to consider here are the intermolecular forces. You have three kinds of molecules (sort of): air, oil, and water. Air molecules bind to themselves only very weakly compared to the other two, and weaker still to the other two types of molecules. Oil is in the middle in terms of self binding, but still doesn't bind very well to water. Water binds amazingly strongly to itself, and weakly to the other two. Thanks to its very strong intermolecular bonds, water will always attempt to minimize its surface area. Now, since air and oil bind only weakly to water, if a group of air or oil molecules is surrounded by water, it will be pushed out by water molecules ferociously attempting to bind to eachother (this is why oil dissolves so weakly in water). So the water will just form a sphere. Oil is the next best at self-binding, so it will be some manner of shell around the water or a blob off on its own. And the air will be on the outside of everything (air gets pushed out of oil the same way it gets pushed out of water). Vapor pressure has nothing to do with this, and oil's inability to dissolve in water has nothing to do with gravity. [[User:Someguy1221|Someguy1221]] 05:43, 2 November 2007 (UTC)
Clarification, I ''thought'' that was it before i looked at that link...darn. [[User:Someguy1221|Someguy1221]] 05:49, 2 November 2007 (UTC)
:Well, I guess what that means is that the hydrogen bonds in water aren't strong enough to overcome its own surface tension and push air bubbles out in zero-g, but then again, the pressure will necessarily be higher on the inside of the water bubble than the outside, I'm sure the air will eventually diffuse out of the water sphere within a few weeks...[[User:Someguy1221|Someguy1221]] 05:59, 2 November 2007 (UTC)

::Such air-water interaction is why you must account for vapor pressure. Note also that air dissolves in water, so "bubbles" do not form. You instead have a homogeneous mixture which is at minimum free energy below a critical temperature, so you'd have to simmer it to get the air out. [[User:SamuelRiv|SamuelRiv]] 06:36, 2 November 2007 (UTC) To clarify: air dissolves in water up at a rate decreasing as one approaches saturation. Bubbles do not form spontaneously in zero-g from air dissolved in water unless it is supersaturated or pressure or temperature change. [[User:SamuelRiv|SamuelRiv]] 06:57, 2 November 2007 (UTC) Clarification: vapor pressure is zero at chemical equilibrium, in which case I believe you're right-surface tension would probably be dominant. [[User:SamuelRiv|SamuelRiv]] 13:58, 2 November 2007 (UTC)

:::Air dissovles only weakly in water. If you watch the youtube link at the top, there are most definately bubbles in the water, in one case a very big stable one. [[User:Someguy1221|Someguy1221]] 06:41, 2 November 2007 (UTC)

:I think we already know the answer to this. Look at a [[Lava Lamp]] - these things work by heating up liquid wax (which repels water just like oil does) until it has the same density as water. What you see is roughly spherical balls of wax floating in the water (because they are trying to minimise their surface area in contact with the water). The lava lamp doesn't do a perfect job - there is a temperature gradient which causes things to move around slowly - but it's pretty clear that in zero g (where the density doesn't matter anymore) - it would be a lot like a kind of idealised lava lamp where there was no temperature gradient. If left long enough, it's pretty clear that it would stabilise into some number of large spheres of one liquid, embedded in the other. If there is still residual swirling and such - then maybe the two liquids would end up on opposite sides of the balloon with a flat interface between the two - because that would be an even more minimal area of contact between them. But a lot is going to depend on whatever residual motion there is when you first take the gravity away. [[User:SteveBaker|SteveBaker]] 14:51, 2 November 2007 (UTC)

::If the was touched the sides of the lamp wouldn't that reduce the surface area interface between the water and the wax? If so why does the wax not stay in touch with the sides of the lamp? [[User:Dichotomous|Dichotomous]] 15:39, 2 November 2007 (UTC)

== What's wrong with global warming? ==

Assuming there is no runaway global warming, what's so bad about the temperature increasing a few degrees, sea level rising a few meters, etc.? From what I've heard, it's generally easier for life to live in warmer than normal climates than cooler. In addition, most life could just move further from the equator. — [[User:DanielLC|Daniel]] 04:27, 2 November 2007 (UTC)
:Have you read [[Effects of global warming]]? -- [[user:Rick Block|Rick Block]] <small>([[user talk:Rick Block|talk]])</small> 04:36, 2 November 2007 (UTC)

:I think you drastically under-estimate the costs here.

:Firstly, there are plenty of life forms that simply cannot "just move" - plants take hundreds or even thousands of years to spread into newly habitable areas - and since climate change is happening on a much faster scale, many species will go extinct in their traditional areas before they can spread into the areas that are newly suited to them. There are cold-weather species (the polar bear for example) who will have no place further north to move to! There are species (birds most notably) who have evolved specifically to fit the migration patterns they've been following for a million years. You can't just move them all a thousand miles further north and expect them to survive just because the temperatures are OK for them there! They may now have to migrate 1,000 miles further to get from their summer feeding grounds to their winter habitats - possibly through areas of much greater heat than they are used to (newly formed deserts perhaps) - and possibly over more ocean than before...they may not have the stamina to do that and their internal maps that are evolved into their brains - not learned will now be incorrect. This will have a knock-on effect on the animals that rely on those plants and birds. Heck, even humans are not able to relocate that easily. How are you going to move the entire city of Houston 1,000 miles north and 5 miles inland? I don't think you are thinking this through!

:Worst still, you are also confusing "Climate" with "Weather". If the local weather changes by a few degrees, it's not a big deal - but if the entire planet's climate changes by that much, it has enormous effects - including the destabilising of established ocean currents and the consequent DRAMATIC effects on local weather patterns. Sea level "rising a few meters" doesn't sound like a lot - but when you think that this puts half a dozen US cities underwater and results in the total submersion of several countries. In most places in the world, the fertile areas where food crops can be grown and most plant and animal diversity can be found is the flatter areas close to the ocean. This means that a small increase in sea level can have a dramatic effect on the ability of a country to feed itself.

:It's just not something that you can just brush off that easily. Plus you can't just "assume no runaway global warming" - that change of a few degrees is plenty enough to cause a few more degrees because of all sorts of positive feed-back effects. The small change at the beginning is the very thing that causes the 'runaway' problem - here in the real world, your "assumption" is simply not a valid one.
: [[User:SteveBaker|SteveBaker]] 14:44, 2 November 2007 (UTC)

== Catapults ==
Here is a question.

Why don't they use catapults to launch planes at Airports like they do on Aircraft Carriers? [[User:202.168.50.40|202.168.50.40]] 04:37, 2 November 2007 (UTC)
:The acceleration is very high, injuring the ontents of the plane, and the planes too big and heavy compared to a fighter. [[User:Graeme Bartlett|Graeme Bartlett]] 04:56, 2 November 2007 (UTC)
::Think of it as a question of scale as well. Imagine firing a marble out of a handheld catapult. Now imagine the catapult needed to fire the ball of glass that represented a jumbo jet. '''<font color="SteelBlue">[[User:Lanfear%27s_Bane|Lanfear's Bane]]</font> | <font color="DimGray">[[User_talk:Lanfear%27s_Bane|t]]</font>''' 13:07, 2 November 2007 (UTC)

Also what would be the point? A runway is cheaper, easier to maintain, doesn't require power, airplanes can launch from it one after the other faster than being loaded on to a catapult one after the other, and there's enough room on planet earth to put one on. Carriers use catapults because there isn't enough room for a full runway. Catapults make it so that the plane doesn't consume as much fuel though, but the other advantages outweigh that. [[User:64.236.121.129|64.236.121.129]] 13:35, 2 November 2007 (UTC)

:There are a lot of simpler ways to save energy at airports that are not commonly used. In some airports in Holland they have these big tractor things that tow aircraft around once they are landed and until they are ready for take-off - these things can tow the plane all the way out to the side of the runway - and when an aircraft lands, there is one of these machines sitting there waiting to tow them back to the terminal. Since it's much more efficient to use wheels to power the movement of the plane than those big fans, it saves fuel AND makes the whole airport much quieter. It's ridiculous that those things are not at every major airport. [[User:SteveBaker|SteveBaker]] 14:25, 2 November 2007 (UTC)

:Also, fighter pilots are highly trained, and the plane isn't meant to be comfy. They probably don't sip coffee and read books during the flight. Nobody would like flying if passenger jets rode like fighter jets. [[User:Friday|Friday]] [[User talk:Friday|(talk)]] 14:43, 2 November 2007 (UTC)

== How long does it take for a sudden cease of gravity to be felt? ==

Imagine that the Sun suddenly vanished. Would the sudden cease of solar gravity be felt on Earth before the 8 minutes and 19 seconds that the last beam of sunlight would take to reach the Earth, or would our planet be plunged into darkness '''before''' we felt the Earth free itself from its solar orbit? In other words, which of these two phenomena would happen first?

And... ''if'' the gravity loss manifested itself before the last beam of sunshine reached the Earth, would that mean the effects of gravity move faster than light? -- [[User:Danilot|Danilot]] 08:26, 2 November 2007 (UTC)
:Changes in a gravitational field move exactly as fast as light. [[User:Someguy1221|Someguy1221]] 08:38, 2 November 2007 (UTC)
::Agree I think it would happen at the same time, the earth would follow the same curve in space (like a water ripple before it flattens) for about 8 minutes and 19 seconds after the sun disappeared we would also receive the last of the light of the now vanished Sun for the same amount of time, after that the Earth would head out in a straight path getting very cold very quickly, the sun will be missed :) ▪◦▪[[User:Sirex98|<span style="background:#44e;color:#bbf">'''≡ЅiREX≡''']][[User_talk:Sirex98|<sup>'''Talk'''</sup>]]</span> 08:55, 2 November 2007 (UTC)

:Conveniently, we have an article on the [[speed of gravity]]. General Relativity anticipates a speed of gravity equal to the speed of light. So far, the experimental results appear to bear this out, but it's a very difficult experiment to do. The earliest direct test was only published in 2003, and even that result has been controversial. [[User:TenOfAllTrades|TenOfAllTrades]]([[User_talk:TenOfAllTrades|talk]]) 13:02, 2 November 2007 (UTC)

:The sun can't just disappear. That would violate local conservation of energy, which is a necessary consequence of general relativity (that is, general relativity can't work at all if energy isn't conserved). So you have to imagine the sun is whisked away somehow. With that caveat, the answers so far are correct.
:The data from [[PSR 1913+16]] strongly confirms the hypothesis that the speed of gravity is ''c''. The article is correct when it says the interpretation of the data is model-dependent, but that's equally true of every scientific measurement. The work of Kopeikin and Fomalont looks wrong to me; from reading the introduction to their paper it looks like they've made the same mistake as Tom Van Flandern, and Steve Carlip's response seems to bear that out. -- [[User:BenRG|BenRG]] 13:40, 2 November 2007 (UTC)

== Is there an acid so strong that it behaves like acid is usually depicted in movies/tv? ==

Like how you see some crooks trying to break into bank, so they spray the side of the wall with acid from a pump, and the acid eats through the wall in seconds. Is there an acid that strong that exists in the real world? Lets assume the wall is made of concrete or wood. [[User:64.236.121.129|64.236.121.129]] 13:50, 2 November 2007 (UTC)
:I think it's possible (I've heard the atmosphere of Venus, having sulphuric acid clouds meaning that anything approaching Venus, if it didn't burn or melt, would corrode before it hit the planet itself), but you'd also have to figure out how on Earth you'd store that acid, and that the concentration is likely to be so high, the acidic clouds would be likely to kill the person spraying the acid... <span style="font-family: Tahoma; font-size: 8pt;">[[User:x42bn6|<b>x42bn6</b>]] <span style="font-size: 7pt;">[[User talk:x42bn6|Talk]] [[Special:Contributions/x42bn6|Mess]]</span></span> 14:18, 2 November 2007 (UTC)

:See [[acid]] for details. The Bronsted-Lowry definition for an acid is a proton donor. Basically, it causes what it touches to be [[redox|oxidized]], or lose electrons. A metal corrodes in acid because it gets oxidized - it dissolves into the acid as it loses electrons and those electrons are taken up by the acid to form hydrogen gas. In the case of [[concrete]], which is made primarily of [[cement]] and water, metal oxides are the primary ingredient. In this case, the metal is already ionized, but the oxygen can give up its extra electrons and form water with the free hydrogen of the acid. So corrosion of concrete is also oxidation-reduction, and the rate reactions depend primarily on the pH of the acid, which depends on its concentration or, perhaps more generally, its [[Hammett acidity function]]. So if the pH is very high, the rate of oxidation-reduction is very high, and the material corrodes quickly. I'm not sure how the reaction for wood ([[cellulose]]) works. [[User:SamuelRiv|SamuelRiv]] 14:28, 2 November 2007 (UTC)
::Whoa there…acidity as a proton donor means it reacts with a base to form a bond, not to abstract the electrons from the base. Other things may indeed happen, but I don't think B–L acid/base strength and redox-potential aren't as directly related as you're suggesting. I'd also point out that "pH is very high" sounds like a very ''weak'' base. [[User:DMacks|DMacks]] 14:52, 2 November 2007 (UTC)

== endothermic vs. exothermic ==

I know exothermic means a system is releasing heat, and endothermic means a system is recieving heat, but if a system was cool to the touch would it be and endothermic or exothermic reaction? It seems like if it was exothermic it would be cool because it was releasing heat, but could also warm because it's giving off heat? Anyone care to help?--<font style="background:red">[[User:MKnight9989|<font color="gold">MKnight</font>]][[User talk:MKnight9989|<font color="gold">9989</font>]]</font> 14:08, 2 November 2007 (UTC)
:Exothermic is roughly equivalent to "energy exiting the system" or "release of energy in the form of heat" - which makes things hotter. Endothermic is "absorption of heat" which makes things colder (because the amount of heat has gone down). If a system is cool to the touch, it means nothing, though - but if the temperature goes down, I'm guessing it's an endothermic reaction. (Note: It's been a while since I studied Chemistry) <span style="font-family: Tahoma; font-size: 8pt;">[[User:x42bn6|<b>x42bn6</b>]] <span style="font-size: 7pt;">[[User talk:x42bn6|Talk]] [[Special:Contributions/x42bn6|Mess]]</span></span> 14:14, 2 November 2007 (UTC)
::Yeah I guess that makes sense. Thanks mate.--<font style="background:red">[[User:MKnight9989|<font color="gold">MKnight</font>]][[User talk:MKnight9989|<font color="gold">9989</font>]]</font> 14:22, 2 November 2007 (UTC)
:::I'd wait for a better explanation, though. Our article on [[exothermic]], for example, looks fairly woeful... <span style="font-family: Tahoma; font-size: 8pt;">[[User:x42bn6|<b>x42bn6</b>]] <span style="font-size: 7pt;">[[User talk:x42bn6|Talk]] [[Special:Contributions/x42bn6|Mess]]</span></span> 14:24, 2 November 2007 (UTC)

::::You don't really specify what is the reaction. Do you mean there is a reaction within the system, or did you want to know if the very act of touching something that felt cold was exothermic/endothermic? If there was a separate reaction and it was cool to the touch, it means that the system was colder than the surrounding environment; heat was taken from the environment (air, container, etc) to fuel the reaction. This heat was transformed, and the total amount of heat in the system is less than what you started with. That means the reaction (that I assume was taking place in the system) was endothermic. Just touching the container isn't really a reaction, just a heat transfer; the total amount of heat is the same. I don't think you could classify it as endothermic/exothermic. But I'll think about it --[[User:Bennybp|Bennybp]] 14:27, 2 November 2007 (UTC)
:::::It was a potassium sulfate/water reaction. --<font style="background:red">[[User:MKnight9989|<font color="gold">MKnight</font>]][[User talk:MKnight9989|<font color="gold">9989</font>]]</font> 14:30, 2 November 2007 (UTC)

== atomic size constraints ==

What keeps an atom from being stable or even formed beyond a certain number of nucleons? Are the forces that hold the atom together not strong enough due to excessive mass or to excessive distance or both? [[User:Dichotomous|Dichotomous]] 15:16, 2 November 2007 (UTC)

== Spherical wheels on cars? ==

Think it will ever happen? I can think of a few advantages they might have. Greater manuverability for one, no need to turn the wheels, simply change the direction of their spin. [[User:64.236.121.129|64.236.121.129]] 15:18, 2 November 2007 (UTC)

:The [[contact patch]] would be much smaller than with a tire, right? That could be a problem. Also you'd need some pretty impressive mechanical magic to give the sphere driving force while still allowing the full range of motion. [[User:Friday|Friday]] [[User talk:Friday|(talk)]] 15:23, 2 November 2007 (UTC)

Revision as of 20:27, 11 October 2008

Template:Future album

Untitled

Theater of the Mind is the sixth upcoming studio album by American rapper Ludacris. It is scheduled to be released on November 25, 2008.[2]

Background

The album was slated for release on October 21, but was pushed back to November 25. In April 2008, a song named "Stay Together" appeared on xxlmag.com;[3] supposedly from the new album. DJ Toomp has also worked on this album.[4] T.I. will also be appearing on a track called "Wish You Would".[5]

The first single "What Them Girls Like" was released on August 7, 2008. The single "co-stars" Chris Brown and Sean Garrett.

The second single "Wish You Would" was released on September 2, 2008. The single "co-stars" T.I.

A video for the song "Undisputed" has been made and first shown on the BET Network. The video features boxer Floyd Mayweather, Jr. and 6-year old boxer Pretty Boy Bam Bam.[6]

Concept

Ludacris says the album is theatrical, conceptual-wise. Every song you hear sounds like a scene from a movie.[7]

Guests

Ludacris stated that none of the tracks will be featuring any guests, instead they will be "co-starring".[5] Confirmed co-stars include Lil Wayne, Floyd Mayweather Jr., Jamie Foxx, The Game[8], T.I., Chris Brown, Nas, Chris Rock, Common, Sean Garrett, T-Pain, Plies, Rick Ross, Spike Lee, Playaz Circle, Willy Northpole[9], Criss Angel[10] and more. The rock band Good Charlotte is planned to have an appearance.[1] Ludacris' fellow Disturbing tha Peace artist, Willy Northpole is scheduled to co-star with The Game.[11] He hopes to work with Eminem for the album.[9]

The Preview

Ludacris released a "Gangsta Grillz" mixtape with DJ Drama called The Preview. The mixtape was released as a download on July 28, 2008.

Confirmed tracks

Title Featured guest(s) Written by Producer(s) Length
"Call Up the Homies"[9] The Game & Willy Northpole C. Bridges, J. Taylor, W. Adams Clinton Sparks 4:06
"Do the Right Thing (Wake Up)"[12] Common & Spike Lee C. Bridges, L. Lynn, S. Lee 9th Wonder
"Everybody Hates Chris"[13] Chris Rock C. Bridges, D. Cannon Don Cannon
"I Do It For Hip Hop"[14] Nas C. Bridges, N. Jones, J. Smith Just Blaze
"Last of a Dying Breed"[15] Lil Wayne C. Bridges, D. Carter, C. Gholston Drumma Boy
"Let's Stay Together"[9] C. Bridges, P. Beauregard DJ Paul 4:18
"MVP"[15] C. Bridges, C. Martin DJ Premier
"One More Drink"[9] T-Pain C. Bridges, F. Najm Trackmasters 3:43
"Southern Gangsters"[16] Playaz Circle & Rick Ross C. Bridges, T. Epps, E. Conyers, W. Roberts
"Undisputed"[6] Floyd Mayweather C. Bridges, F. Mayweather Don Cannon 4:36
"What Them Girls Like"[11] Chris Brown & Sean Garrett C. Bridges, C. Brown, S. Garrett, R. Jerkins Rodney "Darkchild" Jerkins 4:06
"Wish You Would"[5] T.I. C. Bridges, C. Harris, A. Davis DJ Toomp 4:50

References

  1. ^ a b Ludacris Acts Out on September's 'Theater of the Mind'
  2. ^ Ludacris official website
  3. ^ Ludacris "Stay Together" audio.
  4. ^ DJ Toomp: Grammy Family. Accessed July 6, 2008.
  5. ^ a b c Ludacris, T.I. 'Wish You Would' Believe There's No Beef Between Them. Accessed August 8, 2008.
  6. ^ a b ATLien (September 8, 2008). Video ~ Ludacris vs. a 6 Year Old Straight From the A. Accessed September 8, 2008
  7. ^ (July 16, 2008). Ludacris Gets Theatrical on Sixth Album Rap-Up. Accessed August 3, 2008.
  8. ^ Ludacris Interview.
  9. ^ a b c d e Ludacris' Busy Fall: New Album, Two Films. Accessed September 2, 2008.
  10. ^ Ludacris official website
  11. ^ a b Low Key (July 17, 2008). The Ludacris Experience… BET. Accessed August 3, 2008.
  12. ^ http://www.thehiphopchronicle.com/2008/09/18/ludacris-speaks-to-the-hip-hop-chronicle-videoaudio Ludacris Speaks to Hip Hop Chronicle
  13. ^ Gyan's Honorable Mention
  14. ^ Angie Martinez Interviews Ludacris.
  15. ^ a b Hillary Crosley (September 26, 2008). Ludacris Lets Listeners Inside His 'Mind' Billboard. Accessed September 26, 2008.
  16. ^ Listen In On The Ludacris Theather of the Mind Conference Call
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