Thermodynamics is a branch of physics that deals with heat and temperature, and their relation to energy, work, radiation, and properties of matter. The behaviour of these quantities is governed by the four laws of thermodynamics. It applies to a wide range of fields in engineering, especially chemical engineering and mechanical engineering, and also in fields as complex as meteorology. Thermo-dynamics is the subject of the relation of heat to forces acting between contiguous parts of bodies, and the relation of heat to electrical agency.