Sir Joseph John Thomson, a British physicist and Nobel Laureate in Physics, credited with the discovery of the electron, the first subatomic particle that was discovered. Thomson showed that cathode rays were composed of previously unknown negatively charged particles (now called electrons), which he calculated must have bodies much smaller than atoms and a very large charge-to-mass ratio. Joseph John Thomson was born on 18 December 1856 in Cheetham Hill, Manchester, Lancashire, England.
Education
His early education was in small private schools where he demonstrated outstanding talent and interest in science. In 1870, he was admitted to Owens College in Manchester (now University of Manchester) at the unusually young age of 14 and came under the influence of Balfour Stewart, Professor of Physics, who initiated Thomson into physical research. Thomson began experimenting with contact electrification and soon published his first scientific paper. His parents planned to enrol him as an apprentice engineer to Sharp, Stewart & Co. a locomotive manufacturer, but these plans were cut short when his father died in 1873.
Trinity College, Cambridge
He moved on to Trinity College, Cambridge, in 1876. In 1880, he obtained his Bachelor of Arts degree in mathematics (Second Wrangler in the Tripos and 2nd Smith's Prize). He applied for and became a Fellow of Trinity College in 1881. Thomson received his Master of Arts degree (with Adams Prize) in 1883.
Discovery of the electron
Thomson’s most important line of work, interrupted only for lectures at Princeton University in 1896, was that which led him in 1897 to the conclusion that all matter, whatever its source, contains particles of the same kind that are much less massive than the atoms of which they form a part.
They are now called electrons, although he originally called them corpuscles. His discovery was the result of an attempt to solve a long-standing controversy regarding the nature of cathode rays, which occur when an electric current is driven through a vessel from which most of the air or other gas has been pumped out.
Nearly all German physicists of the time held that these visible rays were produced by occurrence in the ether—a weightless substance then thought to pervade all space—but that they were neither ordinary light nor the recently discovered X-rays.
Nobel Prize
He was awarded a Nobel Prize in 1906, "in recognition of the great merits of his theoretical and experimental investigations on the conduction of electricity by gases."
He was knighted in 1908 and appointed to the Order of Merit in 1912. In 1914, he gave the Romanes Lecture in Oxford on "The atomic theory". In 1918, he became Master of Trinity College, Cambridge, where he remained until his death.
Thomson died on 30 August 1940; his ashes rest in Westminster Abbey, near the graves of Sir Isaac Newton and his former student, Ernest Rutherford.
