Summary

DescriptionTranslational motion gif.ogv	Motion of gas molecules Español: Animación mostrando la agitación térmica de un gas. Cinco partículas han sido coloreadas de rojo para facilitar el seguimiento de sus movimientos. Русский: Хаотическое тепловое движение на плоскости частиц газа таких как атомы и молекулы
Date	14 August 1995 (original) 2010-04-09 (converted to OGV)
Source	This file was derived from: Translational motion.gif English: Converted as follows: Download File:Translational motion.gif mplayer.exe Translational_motion.gif -vo yuv4mpeg ffmpeg2theora-0.25.exe stream.yuv --inputfps 20 --framerate 20 --two-pass --videobitrate 200 --output yuv025ifps20fr20twopassbr200.ogv Upload yuv025ifps20fr20twopassbr200.ogv as File:Translational motion_gif.ogv
Author	A.Greg, en:User:Greg L
Other versions

Translational motions—the randomized thermal vibrations of fundamental particles such as atoms and molecules—gives a substance its “kinetic temperature.” Here, the size of helium atoms relative to their spacing is shown to scale under 1950 atmospheres of pressure. These room-temperature atoms have a certain, average speed (slowed down here two trillion fold). At any given instant however, a particular helium atom may be moving much faster than average while another may be nearly motionless. The rebound kinetics of elastic collisions are accurately modeled here. If the velocities over time are plotted on a histogram, a Maxwell-Boltzmann distribution curve will be generated. Five atoms are colored red to facilitate following their motions.

Note that whereas the relative size, spacing, and scaled velocity of the atoms shown here accurately represent room-temperature helium atoms at a pressure of 1950 atmospheres, this is a two-dimensional scientific model; the atoms of gases in the real world aren’t constrained to moving in two dimensions in windows precisely one atom thick. If reality worked like this animation, there would be zero pressure on the two faces of the box bounding the Z-axis. The value of 1950 atmospheres is that which would be achieved if room-temperature helium atoms had the same inter-atomic separation in 3-D as they have in this 2-D animation. p=nm¯c2/3V , where ¯c2 is the mean square speed of the molecules. As according to the gas laws for one mole of gas: pV=RT, where T is the thermodynamic temperature, and R is the molar gas constant, it follows that: RT=nm¯c2/3 Thus, the thermodynamic temperature of a gas is proportional to the mean square speed of its molecules. As the average kinetic energy of translation of the molecules is m¯c2/2, the temperature is given by: T=(m¯c2/2)(2n/3R)

Licensing

This image of simple geometry is ineligible for copyright and therefore in the public domain, because it consists entirely of information that is common property and contains no original authorship.