Measurement The entropy of a substance can be measured, although in an indirect way. The measurement, known as entropymetry, is done on a closed system with constant number of particles and constant volume , and it uses the definition of temperature in terms of entropy, while limiting energy exchange to heat :The resulting relation describes how entropy changes when a small amount of energy is introduced into the system at a certain temperature .
measurement the entropy of a substance can be measured although in an indirect way the measurement known as entropymetry is done on a closed system with constant number of particles and constant volume  and it uses the definition of temperature in terms of entropy while limiting energy exchange to heat the resulting relation describes how entropy changes when a small amount of energy is introduced into the system at a certain temperature 