The intent of this article is to clarify the meaning of entropy and, while doing so, point out how a deeper analysis of entropy in classical statistical mechanics gives us some hints at an underlying quantum description of physical systems.
Thermodynamics and Entropy
The term entropy was coined by 19th century French physicist Sadi Carnot from his scientific study of steam engines. Carnot discovered the mechanical equivalent of heat. A demonstration of which is often given in high school and college physics labs where a falling weight stirs an insulated container of water and the rise in temperature compared to the amount of work done by the falling mass. With that discovery he to some extend and later Rudolf Clausius were able to quantify the extent to which energetic processes were recoverable and how much heat energy could be recovered as useful work.
Clausius’ formula below expresses how this quantity, entropy, changes when a body absorbs or emits heat energy...