i had always thought the temperature the a substance to be a measure up of the typical kinetic energy of the corpuscle in that substance:

$E_k = (3/2) k_bT $

where $E_k$ is the average kinetic energy of a molecule, $k_b$ Boltzmann"s constant, and $T$ the temperature. (I"m not certain of the 3/2 coefficient.) Then i heard from numerous folks the this is a simplistic notion, not strictly true, however they didn"t described what they believed was flawed v this idea. I"d like to understand what (if anything) is objectionable around this idea? Is it that the device must it is in macroscopically in ~ rest? Is it the it ignores the quantum mechanically compelled motion that particles that persists at short temperatures? once is it no valid?


There room a variety of ways of defining temperature, for example using:

$$ partial S over partial E = 1over T $$

This meaning is the basis of an adverse temperatures. This is a instance where the temperature is no a measure of average kinetic energy.

You are watching: What measures the average kinetic energy of particles


The expression your created down because that the power is the expression because that the ensemble average kinetic power of a monatomic right gas. Therefore, we check out that for this system, the average energy of the mechanism is just proportional to the temperature.

For a basic statistical mechanical system, however, it could not even make feeling to talk about the "average kinetic energy" of the system. Because that example, take a quantum mechanism consisting that a solitary spin $1/2$ particle communicating with a magnetic field. That is possible to specify a temperature because that this device when that is in contact with a warmth bath even if the bit is not moving around. In together cases, one appeals to an ext general meanings of temperature such together that come which john Rennie ad in his answer.


temperature the a substance to be a measure up of the mean kinetic energy of the corpuscle in the substance

This is only true because that a monatomic gas. Also without quantum mechanics, a timeless diatomic gas has actually three much more degress of flexibility than a monatomic gas—two rotational and also one vibrational—for a complete of 6. The equipartition organize tells us that the kinetic power will be split equally among these. For this reason the kinetic energy of the gas corpuscle in this situation represents only 1/2 the the power represented through the temperature.


Thanks for contributing solution to barisalcity.org ridge Exchange!

Please be certain to answer the question. Carry out details and share your research!

But avoid

Asking for help, clarification, or responding to various other answers.Making statements based upon opinion; back them increase with recommendations or personal experience.

Use MathJax to layout equations. MathJax reference.

See more: Watch Omamori Himari Episode 1 English Dubbed, Watch Omamori Himari Engsub & Dub Free

To learn more, watch our advice on writing good answers.

write-up Your answer Discard

By click “Post your Answer”, girlfriend agree to our regards to service, privacy policy and cookie policy

Not the price you're spring for? Browse other questions tagged thermodynamics statistical-mechanics temperature or ask your own question.

If temperature is proportional to typical kinetic energy, then is the air around me actually at a higher temperature than, say, my table?

site design / logo design © 2021 stack Exchange Inc; user contributions license is granted under cc by-sa. Rev2021.11.5.40661

your privacy

By click “Accept all cookies”, you agree ridge Exchange have the right to store cookie on your an equipment and disclose information in accordance v our Cookie Policy.