The study of heat processes is called thermodynamics. The processes studied include the effects of heat on various states of matter, and the ways in which heat is related to other forms of energy. (See in this article the subtitles How Substances Are Changed by Heat and Energy Changes and Heat.) All heat processes conform to the fundamental laws of thermodynamics.

states that energy is neither created nor destroyed in the conversion of heat to or from other forms of energy.

states that a transfer of heat from one body to another proceeds naturally and continuously from the warmer to the cooler body.