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Didn't we mess up with the temperature?

  1. Aug 16, 2014 #1
    The following passage has been extracted from the book "The Feynman Lectures on Physics-Vol l":



    From the above passage, at absolute zero, by definition, mean kinetic energy of a molecule should be zero-"completely frozen." There is a giant principle which stands against the view of atoms getting completely frozen; the following passage from the same book introduces the principle:

    Aren't the above two passages in contradiction with each other? Didn't we mess up with temperature?

    The question is also asked in Physics Stack Exchange, interested folks can visit the page: Didn't we mess up with the temperature?

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    Last edited: Aug 16, 2014
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  3. Aug 16, 2014 #2

    Astronuc

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    Staff: Mentor

    The concept or notion of 'temperature' predates our knowledge/understanding of QM, the uncertainty principle and absolute zero.

    As far as humans are concerned, ice, or frozen water is a good basis for 0, as in 0°C. For all intents and purposes, the molecules in ice are frozen solid. Whether or not the atoms are still vibrating is largely irrelevant in common everyday experience.

    http://www.brannan.co.uk/who-invented-the-thermometer

    FYI - Inventing Temperature: Measurement and Scientific Progress (Oxford Studies in Philosophy of Science)
    https://www.amazon.com/Inventing-Temperature-Measurement-Scientific-Philosophy/dp/0195337387

    http://www.nist.gov/pml/div685/grp01/

    The Kelvin and Temperature Measurements
    http://www.nist.gov/calibrations/upload/106-1-01.pdf

    If temperature is a measure of some mean kinetic energy, or translational motion of an atom or molecule, then if it's very very small, it's effectively zero.


    BTW - A Solid Like No Other: Frigid, solid helium streams like a liquid
    http://www.phschool.com/science/science_news/articles/solid_helium.html
     
    Last edited by a moderator: May 6, 2017
  4. Aug 17, 2014 #3

    D H

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    In the first passage, Feynman was writing about an ideal gas, a substance that does not exist. In the second passage, he was writing about the behaviors of real substances. So no, there's no contradiction between those two passages.
     
  5. Aug 17, 2014 #4
    So, ideal gas concept or kinetic "Theory" of gases is not consistent with the principles (laws) of nature.
     
  6. Aug 17, 2014 #5

    D H

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    The concept of an ideal gas and the kinetic theory of gases predates quantum mechanics.

    Thread closed pending moderation.
     
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