Joseph John Thomson (J. J. Thomson, 1856 - 1940) is widely recognized as the discoverer of the electron. Thomson was a Professor of Experimental Physics at Cambridge University, and Director of its Cavendish Laboratory, from 1884 until 1919. It is here where his most well-known, varied and comprehensive work, in the field of conduction of electricity within gases, was undertaken. In 1897 Thompson made an announcement stating that cathode rays were negatively charged particles which he referred to as 'corpuscles', and pronounced that they had a mass some 1,000 times less than a hydrogen atom. Thompson proposed that corpuscles were the items from which atoms were constructed, and concluded that cathode rays possessed a new state by merit of their ability to carry further than the ordinary gaseous state. This was proposed as a state in which all matter is derived from different sources, such as hydrogen or oxygen. This implied that the original discovery was different to the one Thompson now proposed, that the particles were a fundamental element of all matter.
Thompson’s experiment used a pair of plates as electrodes in a glass tube, between which a high voltage potential was applied. When the pressure of the gas in the tube became very low (less than 0.1 atmospheres), an electric discharge took place. This was referred to as vacuum discharge. When the gas pressure in the tube was further reduce...
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...ituation. We would lack an understanding of the anatomy of atoms, and how they are made up of a nucleus with surrounding electrons, and the influence they have on the world around us, and how it works. The importance of electrons would not be appreciated, nor their relevance to experiments on the theory of matter.
1) Anthony Carpi, Ph.D. "Atomic Theory I: The Early Days," Visionlearning Vol. CHE-1 (2), 2003.
2) J.J. Thomson (1897), Cathode rays, Philosophical Magazine, 44, 293 — The classic measurement of the electron mass and charge
3) Thomson, George Paget. (1964) J.J. Thomson: Discoverer of the Electron. Great Britain: Thomas Nelson & Sons, Ltd.
4) Navarro, Jaume, 2005, "Thomson on the Nature of Matter: Corpuscles and the Continuum," Centaurus 47(4): 259-82.
5) Nobel Lectures, Chemistry 1901-1921, Elsevier Publishing Company, Amsterdam, 1966
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