Thermodynamics is the branch of physics that deals with heat, work, and temperature, and their relation to energy, radiation, and physical properties of matter. The behavior of these quantities is governed by the four laws of thermodynamics, which convey a quantitative description using measurable macroscopic physical quantities, but may be explained in terms of microscopic constituents by statistical mechanics.
The development of thermodynamics as a scientific discipline began in the 17th century with the invention of the first vacuum pump and the development of the first steam engines. The first and second laws of thermodynamics were formulated in the 19th century by scientists such as Sadi Carnot, Rudolf Clausius, and Lord Kelvin.
Thermodynamics is a fundamental subject in physics and engineering, with applications in a wide range of fields, including power generation, refrigeration, and materials science. It is also essential for understanding many natural phenomena, from the weather to the functioning of living organisms.