L is the heat of transition.
However, you have no doubt heard that entropy is a measure of the disorder or randomness of a system. The above thermodynamic definition of entropy seems far removed from entropy as randomness. Statistical mechanics is a deeper look into the thermal properties of a system than the look given by thermodynamics. We will give an example in class that will make sense of the statistical interpretation of entropy and introduce new terms such as microstate, macrostate, and probabilities. The course will now end with a discussion of the end of the world.