History of thermodynamics

The word ‘thermodynamics' is derived from the Greek therm, or heat and dynamis, or force.

The term originally referred only to the study of heat, but its scope expanded as scientist learned more about the nature of both heat and work. Thermodynamics as a branch of science was established in the 19th century by pioneers as Sadi Carnot, Robert Mayer, Hermann Helmholtz, William Thompson and Rudolf Clausius.

In about 500 BC Heraclitus regarded fire as an element, which with water earth and gas were four independent elements in nature.

In about 300 BC Zhou Yan of Warring States in ancient China proposed a hypothesis of five elements that metal, wood, water, fire and earth composed the physical universe.

The invention of the steam engine in the 18th century triggered the issue of the relation between heat and work among engineers and physicists.

In 1798, Count Rumford observed that the heat generated during boring of cannons was approximately proportional to the work done.

In 1824 Sadi Carnot, French Army engineer, proposed Carnot theorem. The theorem made a foundation for a new discipline of thermodynamics, which was entirely different from Newton mechanics. He realized that a heat engine could perform work only by taking heat from one reservoir and transferring it to another at a lower temperature.

He published a masterly memoir on the subject ‘Reflection on the Motive Power of Heat’.

Robert Mayer (1814-1878) was the first who formulated the law of energy conservation. In 1842 he published his paper in Liebig’s Annalen is clearly expressing the equivalence of work and heat.

In 1840, Joules’ experiments provided confirmation and led to the concept of Mechanical Equivalent of Heat. It was later generalized into Law of Conservation of Energy, which states that ‘energy can neither be created or destroyed; it can be only transformed from one form into another.’

On July 23, 1847 Hermann Helmholtz reported to ‘Berliner Physikalische Gesellschaft’ about his research on the principle of conservation of energy.
 History of thermodynamics