The equations are named after the American physicist Percy Williams Bridgman.
The four most common thermodynamic potentials are: The first derivatives of the internal energy with respect to its (extensive) natural variables S and V yields the intensive parameters of the system - The pressure P and the temperature T .
For a simple system in which the particle numbers are constant, the second derivatives of the thermodynamic potentials can all be expressed in terms of only three material properties Bridgman's equations are a series of relationships between all of the above quantities.
Many thermodynamic equations are expressed in terms of partial derivatives.
For example from the equations below we have: and Dividing, we recover the proper expression for CP.