Thermodynamics: Where exactly does microscopic turn to macroscopic?

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SUMMARY

The discussion centers on the transition from microscopic to macroscopic thermodynamics, emphasizing that the critical factor is not a specific distance scale but rather the number of particles involved. It is established that as few as 100 particles can be treated as a thermodynamic continuum, while up to 1012 particles may still exhibit noticeable effects, such as Brownian motion, that deviate from continuous thermodynamic behavior. This highlights the complexity of defining the boundary between microscopic and macroscopic phenomena in thermodynamics.

PREREQUISITES
  • Understanding of statistical mechanics
  • Familiarity with thermodynamic variables
  • Knowledge of particle dynamics
  • Concept of Brownian motion
NEXT STEPS
  • Research the principles of statistical mechanics in thermodynamics
  • Explore the concept of thermodynamic limits and particle number scaling
  • Study the effects of Brownian motion on thermodynamic systems
  • Investigate the transition from microstates to macrostates in statistical physics
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Students and researchers in physics, particularly those focused on thermodynamics, statistical mechanics, and particle dynamics.

mikeph
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Looking for a rough distance scale over which statistical methods begin to work, and macroscopic thermodynamic variables begin to make sense. Thanks
 
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It is rather not distance scale, but number of particles involved.

It depends on how subtle effects you want to describe.
Sometimes 100 particles may be successfully treated as a thermodynamical continuum, sometimes 1012 or so still produce visible effects (Brownian moves) beyond continuous thermodynamics.
 

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