Temperature is a thermodynamic value for a body that is a measure of the mean kinetic energy of the disordered motion of the particles that make up the body. The SI unit of temperature is the Kelvin; the Celsius and Fahrenheit scales are also in use. Temperature is an intensive physical quantity – when you divide a body, both parts have the same original temperature.
When two bodies of different temperature are brought into contact with one another, heat energy is transferred from the higher-temperature body to the lower-temperature body until thermal equilibrium is established, that is, the temperatures become equal.
Temperature affects numerous processes in physics and chemistry and therefore has great importance for many technical processes. The temperature measurement is therefore an indispensable measurement technique in many technical applications. It can be done with and without contact.