# Time interval

A time interval - also time interval , time segment , time span , period , while , time phase or time period - is a more or less extended part of time as duration. A long time interval is also known as a long time .

A time interval, viewed as a section on a time scale , has a beginning and an end, each of which can be determined by a point in time . Thus, a time interval can be understood as a time difference in the same reference system and a metrologically determined time span can be used for the time measurement , such as B. with an interval counter . The time difference measured for the time interval is often given as. The term interval goes back to the Latin term inter vallos for the space “between the palisades ”. ${\ displaystyle \ Delta t}$

In addition to the general basic time intervals - such as between two sunrises as full day , or between two Sonnentiefstständen as a tropical year or the time interval the nuclear seconds  - are in today's science numerous specific time periods measured: For example, the average time between two radioactive decay to calculating the decay rate of a substance, or between two cell divisions to calculate the growth rate of a tissue or the time in which a Foucault pendulum an angle of one degree travels to determine the earth's rotation .

The in modern physics shortest period of significance is after the physicist Max Planck called Planck time (about 10 -43  s), which is also the definition limit of time continuum represents. The longest physically determinable period of time is the time that has passed from the Big Bang to the present day as the age of the world , approximately 14 billion years (14 Ga) or 4.4 · 10 17 seconds. The age of the earth is estimated at about 4.6 billion years (4.6 Ga), its history is divided into different periods of time (see geological time scale ).

A neuropsychologically important period of time is the duration of that moment that we subjectively experience as the present and in which we grasp impressions as now together. According to various studies, this span should last around three seconds and be quantified in around one hundred parts , each comprising intervals of around 30 ms (and thus above the synaptic latency period of excitation transmission at fast chemical synapses). For example, noises up to 0.03 seconds short can be differentiated according to their sequence and resolved over time as a sequence (for temporal reference see also personal equation ).

Time interval meaning
shake 10 nanoseconds, outdated time unit for atomic processes
Second (s) Basic unit of the basic quantity time in the ( SI ) system of units
moment quite short, not precisely determined time span
moment indefinitely similar to moment ( medieval momentum was 140 hour)
Minute (min) 60 seconds
School lesson 45, 50, 55, 60, 67.5 or 90 minutes
Hour ( h , lat.hora) 60 minutes
Glass 4-hour watch on seagoing vessels
Day ( d , lat. Dies) 24 hours
week 7 days
month 28 or 29 for a leap year, 30 or 31 days
quarter 14 year (3 months)
Trimester 3 months (prefix tri , as in semester , based on the number of months)
Tertial 4 months
semester 6 months (sex menses)
Year ( a , lat.annum) 12 months, 365 or 366 days for a leap year
Biennium 2 years
Olympics 4 years
Quinquennium or Lustrum ( year five ) 5 years
Hebdomade or week of the year (seven of the year) 7 years
Octaeteris 8 years
Year dozen (a dozen years) 12 years
Centennium or hectode ( century ) 100 years
Millennium ( millennium ) 1,000 years
Million years ( Ma ) 1,000,000 years
Billion years ( Ga ) 1,000,000,000 years

## literature

• Dietrich Pelte: Physics for Biologists . Springer, Heidelberg 2005, ISBN 3-540-21162-4 .
• D. Sautter, H. Weinerth: Lexicon Electronics and Microelectronics . Springer, Berlin 1993, ~ 10 positions [1]
• Albert Schödlbauer : Geodetic Astronomy: Basics and Concepts . Walter de Gruyter, Berlin / New York 1999, ISBN 3-11-015148-0 , ~ 20 characters [2]