Entropy, Order and Disorder

Entropy is one of the few physical properties of a system that cannot be measured directly, but must be deduced or calculated from other properties. It is also a property that has been defined in a rather abstract sense and has not been connected to another observable property or physical variable. Since its formulation as a thermodynamic property, entropy has been linked to the concepts of order, disorder and chaos in ways that are often confusing and scientifically misleading. From the point of view of engineering systems and the subject of Classical Thermodynamics, there is no obvious or even tentative connection between entropy and the “order” or “disorder” of the thermodynamic systems. This short paper gives several examples that demonstrate the disconnection between entropy and disorder in thermodynamic systems.