August Beer (] ; 31 July 1825 – 18 November 1863) was a German physicist, chemist, and mathematician.
 Beer was born in Trier, where he studied mathematics and natural sciences. Beer was educated at the technical school and gymnasium of his native town until 1845, when he went to Bonn to study mathematics and the sciences under the mathematician and physicist Julius Plücker, whose assistant he became later.
 In 1848 he won the prize for his essay, "De Situ Axium Opticorum in Crystallis Biaxibus," and obtained the degree of Ph.D.
 Two years later he was appointed lecturer at the University of Bonn.
The vapour pressure of water is the pressure at which water vapour is in thermodynamic equilibrium with its condensed state.
 At higher pressures water would condense.
 The water vapour pressure is the partial pressure of water vapour in any gas mixture in equilibrium with solid or liquid water.
 As for other substances, water vapour pressure is a function of temperature and can be determined with the Clausius–Clapeyron relation.
The Antoine equation is a class of semi-empirical correlations describing the relation between vapor pressure and temperature for pure components.
 The Antoine equation is derived from the Clausius–Clapeyron relation.
 The equation was presented in 1888 by the French engineer (1825–1897).
Charlotte Riefenstahl (24 May 1899 in Bielefeld, Germany – 6 January 1993 in Northfield, Minnesota, United States ) was a German physicist.
 She has no relation to Leni Riefenstahl, the notable German filmmaker.
Ehrenfest equations (named after Paul Ehrenfest) are equations which describe changes in specific heat capacity and derivatives of specific volume in second-order phase transitions.
 The Clausius–Clapeyron relation does not make sense for second-order phase transitions, as both specific entropy and specific volume do not change in second-order phase transitions.
Rudolf Julius Emanuel Clausius (2 January 1822 – 24 August 1888) was a German physicist and mathematician and is considered one of the central founders of the science of thermodynamics.
 By his restatement of Sadi Carnot's principle known as the Carnot cycle, he gave the theory of heat a truer and sounder basis.
 His most important paper, "On the Moving Force of Heat", published in 1850, first stated the basic ideas of the second law of thermodynamics.
 In 1865 he introduced the concept of entropy.
 In 1870 he introduced the virial theorem which applied to heat.
Benoît Paul Émile Clapeyron (] ; 26 February 1799 – 28 January 1864) was a French engineer and physicist, one of the founders of thermodynamics.
Louis Semple Clarke, or Simpson Clarke or simply LS, was a pioneering businessman and engineer in the American automotive industry.
 One of the central founders of The Autocar Company, Clarke was also an inventor who made numerous contributions to the development of modern motor vehicles, including innovations in the use of the drive shaft, circulating motor oil, sparkplugs, and the American convention of placing a vehicle's steering wheel on the left.
Hermann Julius Oberth (] ; 25 June 1894 – 28 December 1989) was an Austro-Hungarian-born German physicist and engineer.
 He is considered one of the founding fathers of rocketry and astronautics, along with the French Robert Esnault-Pelterie, the Russian Konstantin Tsiolkovsky and the American Robert Goddard.
The Clausius–Clapeyron relation, named after Rudolf Clausius and Benoît Paul Émile Clapeyron, is a way of characterizing a discontinuous phase transition between two phases of matter of a single constituent.
 On a pressure–temperature (P–T) diagram, the line separating the two phases is known as the coexistence curve.
 The Clausius–Clapeyron relation gives the slope of the tangents to this curve.
 Mathematically,

Question: The Clausius–Clapeyron relation was named after a German physicist and mathematician who is considered one of the central founders of what area of science?
Answer: the science of thermodynamics