Thermodynamics of frost heaving: A thermodynamic proposition for dynamic phenomena

A phenomenon of up-heaving during the freezing of water in porous materials is reviewed. A unique feature relevant to the phenomenon is that when water and ice are partitioned by a microporous material and are kept in a supercooled state, water moves from below to the ice bottom against a force of gravity, and gravitational potential energy is spontaneously produced. This phenomenon, which is unable to be explained by Newton's laws of dynamics, is found to be consistent with the second law of thermodynamics. It is suggested that matter in a system kept in a thermodynamically nonequilibrium state can move in a direction opposite to a force applied on the matter if the movement produces an increment of entropy in a whole system consisting of the system and local surroundings that interact with the system. The result is generalized and a simple thermodynamic proposition is proposed so as to account for emergence of dynamic motions in nonequilibrium systems. Some of the examples are discussed from this thermodynamic viewpoint.