If two bodies that have different temperatures come together, a transfer of energy takes place in the form of heat (from the hot body to the cold one), until finally the temperatures of both bodies become equal.
In physics, it is defined as a magnitude of internal energy of a thermodynamic system. There are many substances that change depending on the temperature at which they are , such as their volume, solubility, electrical conductivity or state (solid, liquid or gas).
The temperature can be measured with a thermometer, the most common is that of liquid enclosed in glass. The unit of temperature par excellence is the kelvin (K) , according to the International System of Units, to which the Kelvin scale corresponds. Outside of the scientific field, the Celsius scale is usually used, also called Centigrade; in the United States, -and to a lesser extent-, Fahrenheit is used.
