The History of Temperature Scales

Temperature is thermodynamic property of objects. It is an “indirect measure of the kinetic energy of the particles that make up matter” (Lerner 2008). Temperature determines the direction of the flow of energy between two objects. When they are put in contact with each other, the faster-moving molecules of higher temperature object will collide and increase moving speed of slower-moving molecules of the lower temperature object. This process stops when both objects have the same average molecular kinetic energies, or in other words, they are in thermal equilibrium with each other. Temperature is one of the most commonly measured parameters. Thermometer is a device that has an established temperature scale, based on its expansion property at different temperatures. When the thermometer is in thermal equilibrium with other objects, it indicates the degrees of objects’ temperatures. Temperature is measured against four temperature scales: Fahrenheit (F), Celsius (C), Kelvin (K), and Rankine (R) temperature scales, which names are based on the names of scientists who originated the temperature scales.

The Fahrenheit scale, denoted by letter F, is a non-metric temperature scale, developed in early 18th century by a German physicist, Daniel Gabriel Fahrenheit (1686-1736). On this scale, the normal freezing point (or ice point) of water is at 32 oF, and normal boiling point (or steam point) of water is at 212 oF. Originally, Fahrenheit chose 0oF for the coldest temperature he could made in his lab (by mixing ice and salt water) and 96oF a “convenient number with many factors for subdivision” for human body temperature (Tipler 565).

The Celsius scale, denoted by letter C, is a metric temperature scale, developed in 1742 by a Swedish astr...

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