Basic theory - Temperature may be viewed as a measure of a quality of heat, as distinct from a quantity of heat.[1][2][3][4] The quality is called hotness by some writers.[5][6]
When two systems are at the same temperature, no heat transfer occurs spontanteously, by conduction or radiation, between them. When a temperature difference does exist, and there is a thermally conductive or radiative connection between them, heat transfers spontaneously from the warmer system to the colder system, until they are at mutual thermal equilibrium. This transfer occurs by heat conduction or by thermal radiation.[7][8][9][10][11][12][13][14]
Experimental physicists, for example Galileo and Newton[15], found that there are indefinitely many empirical temperature scales.
