Kelvin , William Thomson

Kelvin , William Thomson, Baron Kelvin of Largs

(1824–1907) British theoretical and experimental physicist

Born in Belfast, Northern Ireland, William Thomson was an extremely precocious child intellectually and matriculated at Glasgow University at the astonishingly early age of 10. He went on to Cambridge, after which he returned to Glasgow to become professor of natural philosophy. He was to occupy this chair for 53 years. It was in Glasgow that he organized and ran one of Britain's first adequately equipped physical laboratories. In 1892 in recognition of his contributions to science he was raised to the British peerage as Baron Kelvin of Largs. He was also a devout member of the Scottish Free Church.

Kelvin's work on electromagnetism was also important. Together with Faraday he was responsible for the introduction of the concept of an electromagnetic field. Kelvin was of a much more mathematical turn of mind than Faraday, but it was left to Maxwell to weld the ideas of Faraday and Kelvin together into a powerful, elegant, and succinct mathematical theory. But Maxwell's work would have been greatly hampered without some of the penetrating suggestions made by Kelvin. Particularly important is a fundamental paper of 1847 in which Kelvin drew an analogy between an electrostatic field and an incompressible elastic solid. Kelvin made many other innovations including the introduction of the use of vectors to represent magnetic induction and magnetic force. He also put his knowledge of electromagnetism to use in many practical inventions of which the transatlantic electric telegraph cable and the mirror galvanometer were among the most important.

Kelvin's other great area of work was thermodynamics. He was one of the first to understand and appreciate the importance of James Joule's seminal work in the field. In his 1852 paper on theDissipation of Mechanical Energy Kelvin set out the fundamentally important law of conservation of energy that was to be so important in the physics of the second half of the 19th century. In his work on thermodynamics Kelvin assimilated and developed the work of the great pioneers of the subject, Nicolas Carnot and James Joule. He also collaborated with Joule in experimental work. One of the important results of Kelvin's work was his introduction of the concept of absolute zero and his recognition of the theoretical importance of the absolute scale of temperature, which is named in his honor. Kelvin was able to calculate the value of absolute zero from theoretical considerations. One of the first formulations of the second law of thermodynamics was given by Kelvin. With Joule he first demonstrated the Joule–Kelvin effect. He also made important contributions to the theory of elasticity and some basic contributions to hydrodynamics in which he collaborated with George Stokes. The unit of thermodynamic temperature, thekelvin, is named after him.