In thermodynamics, absolute temperature is a temperature scale, such as one in degrees kelvin or rankine, not related to the physical properties of any particular substance and measured with reference to absolute zero. [1]

The the early Reaumur, Fahrenheit, and centigrade scales were an “arbitrary series of numbered points on a scale”, according to Irish-born Scottish physicist William Thomson, who reasoned instead that each interval of degrees on a “absolute” scale would need to measure or represent the same exact amount of work, using Carnot’s notion that a given amount of heat passing between two temperatures can produce only a particular amount of work. Thomson adopted the absolute zero number of Victor Regnault who had determined -272.75 ˚C, by four different methods. [3]

Thomson published his “absolute” temperature scale in 1848. [2] Irish physicist William Rankine also proposed a similar scale in the following years.

1. Perrot, Pierre. (1998). A to Z of Thermodynamics (absolute temperature, pg. 2). Oxford University Press.
2. Thomson, William. (1848). “On an Absolute Thermometric Scale Founded on Carnot’s Theory of the Motive Power of Heat” (pgs. 100-06), Cambridge Philosophical Society Proceedings for June 5; and Phil. Mag., Oct. 1848.
3. Shachtman, Tom. (1999). Absolute Zero and the Quest for Absolute Cold (pg. 98). Mariner Books.

External links
Absolute temperature – Eric Weisstein’s World of Physics.
Absolute temperature scale – Encyclopedia Britannica.

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