Temperature is a physical quantity that indicates the degree of heat or cold of an object, and microscopically speaking, it is the degree of intensity of heat movement of molecules of an object. Temperature can only be indirectly measured by some of the characteristics of the object with the temperature change, and used to measure the value of the object temperature scale called temperature scale. It specifies the starting point of temperature reading (zero point) and the basic unit of temperature measurement. International units for thermodynamic temperature scale (K). At present, the international use of other temperature scale is more Fahrenheit temperature scale (° F), Celsius temperature scale (° C) and the international practical temperature scale. From the viewpoint of molecular kinematics, temperature is the sign of the average kinetic energy of the molecular motion of an object. Temperature is the collective expression of the thermal motion of a large number of molecules and contains statistical significance. For individual molecules, temperature is meaningless. The degree of heat or cold measured according to one of several arbitrary scales based on an observable phenomenon (e.g., the expansion of a column of mercury).