Thermodynamics

The theory of heat and temperature, encompassing both the macroscopic behavior of bodies, and the statistical description of the submicroscopic world of particle motions.

Laws of Thermodynamics:

1. First Law: A statement of the conservation of energy: The change of the energy of a system is equal to the heat added plus the work done on the system.
2. Second Law: The Entropy of an isolated system can only increase with time. Also can be stated: heat never flows spontaneously from a cooler to a hotter body. (Perpetual motion is impossible.) See Also: Arrow of Time.
3. Third Law: Absolute Zero can never be attained, only approached arbitrarily closely.