Is entropy extensive?

Posted by on Dec 28, 2012 in Science | 0 comments

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...

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Action, energy, entropy

Posted by on Dec 19, 2012 in Science | 0 comments

Among of the most truly singular developments of classical mechanics are Lagrangian and Hamiltonian mechanics. This observation has been made many times by folks much more well known than yours truly, and so my humble voice is but a whisper in a chorus of lions, as it were. Still, the observation is true. Up to the formulation of Lagrangian and Hamiltonian mechanics, the equations of physics were presented as differential equations. This implies that the motion of a particle is given as a highly local interaction of forces acting instantaneously. The trajectory of a particle is solved...

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