Heat is defined as energy in process of transfer between a system and its surroundings as a result of temperature differences. The term is also used to refer to the energy contained in a sample of matter. Temperature is a measure of whether two systems are relatively hot or cold with respect to one another. A thermometer, using a temperature scale established with respect to an arbitrary zero, is required to establish the relative temperatures of two systems (Chambers 1988,420&889).
The Maynooth Heat Collection consists mainly of thermometers of different scales and designs, together with teaching instruments used for class demonstration or experimental purposes. Some other instruments in the collection incorporate a thermometer, but the listing under heat describes only those whose main function is to measure heat.

The collection can be broken down into expansion, friction, and thermometers, and then various other instruments.

Expansion