less than 1 minute read


Entropy Is Additive

If two systems with entropy S1 and S2, respectively, are brought into contact with each other, their combined entropy equals S1 + S2. This is assured by the logarithmic relationship between S and Pmax, as follows: If the number of microstates corresponding to the most likely distribution of the first system is Pmax1 and that of the second system is Pmax2, then the number of possible microstates of the most likely distribution of the combined system is simply Pmax1Pmax2. It is a fundamental properties of logarithms that ln(ab) = ln(a) + ln(b), so if S1+2 is the entropy of the combined system, then

Additional topics

Science EncyclopediaScience & Philosophy: Electrophoresis (cataphoresis) to EphemeralEntropy - Entropy Is A Probabilistic Property, Entropy Is Additive, Entropy Is Not Conserved - Entropy measures disorder