Temperature is a measure of the average translational kinetic energy of the molecules of a system. Heat is commonly expressed in either of two units: the calorie , an older metric unit, and the British thermal unit (Btu), an English unit commonly used in the United States. Scientists express heat in terms of the joule , a unit used for all forms of energy.
As heat is added to a substance in the solid state, the molecules of the substance gain kinetic energy and the temperature of the substance rises.
