Entropy (order and Disorder) - Difficulties With The Term "disorder"

Difficulties With The Term "disorder"

In recent years the long-standing use of term "disorder" to discuss entropy has met with some criticism.

Whilst when considered at a microscopic level the term disorder may quite correctly suggest an increased range of accessible possibilities, confusion may be caused because at the macroscopic level of everyday perception a higher entropy state may appear more homogenous, more even or more smoothly mixed—apparently in diametric opposition to its description as being "more disordered". Thus for example there may be dissonance at equilibrium being equated with "perfect internal disorder"; or the mixing of milk in coffee from apparent chaos to uniformity being described as a transition from an ordered state into a disordered state.

It has to be stressed, therefore, that "disorder", as used in a thermodynamic sense, relates to a full microscopic description of the system, rather than its apparent macroscopic properties. Many popular chemistry textbooks in recent editions increasingly have tended to instead present entropy through the idea of energy dispersal, which is a dominant contribution to entropy in most everyday situations.