Temperature
Temperature is a physical property of matter that provides a measure of the average kinetic energy of molecular motion in an object or system. Temperature can be defined as a state of a body in which heat is transferred from one system to another. It is important to note that there is a difference between temperature and heat.
Temperature is a measure of the internal energy of a system, whereas heat is a measure of the transfer of energy from one system to another. Heat transfer occurs from a body at a higher temperature to one at a lower temperature. The two bodies are said to be in thermal equilibrium when they are at the same temperature and no heat is transferred between them. The increase in temperature of a body is due to a greater absorption of heat, which increases the movement of molecules within the body.
Temperature is an intense physical quantity, and this means that in order to define it conceptually, it must be evaluated in terms of the effects that its variations have on the behaviour of materials. In fact, the temperature is evaluated as a function of the average kinetic energy possessed by the atoms constituting the matter and describes the thermodynamic state of the systems in equilibrium.
Furthermore, once the unit of measurement has been defined, it is not possible to define a multiple or sub-multiple of it; since temperature is an intensive quantity, if two bodies of unitary temperature are brought into contact, the set made up of the two bodies still has a unitary value. It will therefore be necessary to define not only the unitary quantity, but also every multiple and sub-multiple of it, that is, to define a thermometric scale.