ABSTRACT
This chapter addresses one of the most profound of phenomena in Thermodynamics as well as Statistical Mechanics, namely, Critical Phenomena. In plain terms, this is a study of the occurrence of the so called critical points and their properties. The vdW equation is easily the simplest equation of state for a system that displays liquefaction of gases. In the vdW system, the critical point appears as a point of termination of the phase coexistence curve. This is a feature that is experimentally observed in many systems. In fact critical exponents can be introduced for any approach along a given path so that there is only one dependent variable, and study how some physical quantity like latent heat and surface tension behaves as one approaches the critical point. The advantage of an explicitly analytic model like vdW theory is that one can study the behaviour of any physical quantity one is interested in any region of the space of thermodynamic variables.
