isothermal compressibility

Isothermal compressibility is a measure of how much a substance's volume changes when pressure is applied, while its temperature remains constant. It is the inverse of the bulk modulus, which quantifies a material's resistance to uniform compression.12

Specifically, isothermal compressibility (\u03b2_T) is defined as the relative decrease in volume per unit increase in pressure under isothermal conditions. This property is crucial in fluid mechanics, especially when heat transfer can occur during compression. For gases, isothermal compressibility is related to pressure and density, while for liquids, it is generally much smaller. A substance that is difficult to compress has a large bulk modulus and low compressibility.312