The German physicist Max Planck used Walther Nernst's heat theorem to define the third law of thermodynamics in terms of entropy and absolute zero. The third law of thermodynamics allows us to find the absolute value of entropy, which cannot be done within classical thermodynamics. In other words: it is impossible to reduce the absolute entropy of a system to its absolute zero value in a finite number of operations. Nernst TheoremĪ chemical reaction between pure crystalline phases that occurs at absolute zero does not produce any change in entropy. The most essential theorems and statements related to the third law of thermodynamics are: 1. Theorems and Statements of the Third Law of Thermodynamics As they are not perfect crystals, the information necessary to describe the existing defects will increase the entropy of the crystal. Consequently, they will have defects that will not be removed by cooling to absolute zero. However, this observation does not consider that real crystals have to be formed at temperatures above zero. Nernst's theorem states that the entropy of a perfect crystal of any element at absolute zero temperature is zero. It is because, at absolute zero temperature, a system is in a ground state, and entropy increases are achieved by degeneracy from this ground state. This principle states that the entropy of a system at absolute zero temperature is a well-defined constant. The third law of thermodynamics, sometimes called Nernst's theorem or Nernst's Postulate, relates to the entropy and temperature of a physical system. When we are reaching absolute zero, the entropy reaches a minimum and constant value.

The third law of thermodynamics can also be defined as that when reaching absolute zero - 0 degrees kelvin - any process of a physical system stops. The third law of thermodynamics states that absolute zero cannot be reached in a finite number of steps.

Absolute third law entropy