The ‘Brownian ratchet’ and its relevance to the second law of thermodynamics.

  • Thread starter YoshiBeans
  • Start date
My question is regarding the reason why the Brownian ratchet fails to negate the second law.

The explanation that I have been told relates to the fact that the molecules in the second chamber would interact with the 'pawl' in a similar manner to those interacting with the paddle wheel, negating the overall useful rotation.

I have also been told that if T1 is higher than T2, then it will produce useful work, but that this complies with the laws by acting like a heat engine.

My question is: How can the same failure to extract useful work be explained if there was a vacuum in the second chamber? This would negate the temperature comparison, and would seem to allow the extraction of work from the first chamber.

I would appreciate any available illumination. Thank you.


Feynman_ratchet.png
 
I would really like to know this too.
 

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