## Is entropy extensive?

There is a very general theme in modern physics instruction to the effect that the originators of statistical mechanics got the expressions for entropy wrong, in that they were not extensive. It’s often pointed out that Gibbs was among the first to correct Boltzmann’s original statistical expression for entropy, in order to make it extensive, as a consequence of noting what’s referred to as Gibb’s paradox. The Wikipedia article on Gibb’s paradox, just linked to, illustrates the issue by supposing two equal volumes of a similar ideal gas separated by a removable...

Read More## The origin of “entropy”

The concept of entropy arose historically in the development of thermodynamics. Clausius introduced the term entropy in 1865 while working on the theory behind the Carnot cycle. Sadi Carnot had begun the entire edifice of thermodynamics with his studies on the efficiency of steam engines. Carnot published his basic finding in an 1824 book, Reflections on the Motive Power of Fire and on Machines Fitted to Develop that Power. The brilliance of the Internet is such that you can find the volume in an English translation at Archive.org here. The translation also includes comments on...

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