How to Win Any Debate: Claim You Understand Entropy!

John von Neumann (1903-1957) was a very clever mathematician who offered the following advice:

• No one really knows what entropy really is, so in a debate you will always have the advantage (by pretending that you know).

This is still true, and causes a lot of confusion. If you want to improve your understanding then you could consult Computational Thermodynamics, which presents the 2nd Law of Thermodynamics resulting from the Euler equations for a compressible gas subject to finite precision computation in the following integrated form, with the dot signifying time differentiation (see the previous post):

• $\dot K+\dot P = W-D$
• $\dot E = -W + D$,  

where $K$ is kinetic energy, $P$ potential energy, $W$ work, $E$ heat energy and $D\ge 0$ is turbulent dissipation with $W > 0$ under expansion and $W < 0$ under compression. The sign of $D$ sets the direction of time with always transfer of energy from $K+P$ to $E$ from turbulent dissipation.

Here turbulent dissipation is the same as entropy production or the other way around:

• Entropy production is the same as turbulent dissipation. 

This removes the mystery from entropy and you can now win any debate, by really knowing what entropy is! 

For application an application see the recent post on Basic Atmospheric Thermodynamics and the 2nd Law.