19th century in science Carnot captured some of the ideas of thermodynamics in his discussion of the efficiency of an idealized engine. Sadi Carnot's work provided a basis for the formulation of the first law of thermodynamics—a restatement of the law of conservation of energy—which was stated around 1850 by William Thomson, later known as Lord Kelvin, and Rudolf Clausius. Lord Kelvin, who had extended the concept of absolute zero from gases to all substances in 1848, drew upon the engineering theory of Lazare Carnot, Sadi Carnot, and Émile Clapeyron–as well as the experimentation of James Prescott Joule on the interchangeability of mechanical, chemical,
Laws of thermodynamics third law of thermodynamics is sometimes stated as follows: At zero temperature the system must be in a state with the minimum thermal energy. This statement holds true if the perfect crystal has only one state with minimum energy. Entropy is related to the number of possible microstates according to: Where "S" is the entropy of the system, "k" Boltzmann's constant, and "Ω" the number of microstates (e.g. possible configurations of atoms). At absolute zero there is only 1 microstate possible ("Ω"=1 as all the atoms are identical for a pure substance and as a result all orders are identical