Thomson, Sir Joseph

Royalty-Free/Corbis. Reproduced by permission p. 209 Yen dell, Thomas, a Thalidomide baby, picks up a toy with his feet, photograph. AP/Wide World Photos. Reproduced by permission p. 215 Thallium heart scan, photograph by Peter Berndt, M.D. Custom Medical Stock Photo. Reproduced by permission p. 226 Thomson, Sir Joseph John, photograph. UPI/Corbis-Bettmann. 

Thomson, Sir Joseph John (1856-1940) British physicist, who became a professor at Cambridge University in 1884. He is best known for his work on cathode rays, which led to his discovery of the electron in 1897. He went on to study the conduction of electricity through gases, and it is for this work that he was awarded the Nobel Prize for physics in 1906. 

Sir Joseph Thomson (1856-1940 Nobel Prize for physics 1906) discovered the free electron in 1897 and researched its properties. On the basis... 

That eminent physicist, Sir Joseph Thomson, had entered the field of analytical chemistry, and had invented an absolutely new system of chemical analysis. There was also Prof. Strutt with his active nitrogen, whilst Prof. Rutherford, in his wonderful researches on radioactivity, had revealed the existence of a whole series of new elements. Those eminent physicists had discovered, what chemists had long known, that the science was the most exacting of mistresses, making more imperious demands on the time and patience of her votaries than any of her sisters. (Proceedings of the Chemical Society, 99)... 

British physicist Sir Joseph John Thomson (1856-1940) discovers the electron. 

By the early twentieth century, chemists and physicists recognized that the atoms of which chemical elements are composed are themselves made up of electrons and protons, of electrically negative and positive subatomic particles that were the universal constituents of all chemical elements. Sir Joseph Thomson had discovered the electron in 1897. Ernest Rutherford postulated the existence of a positive nucleus in atoms in 1911, and he used this in developing his planetary model of the atom, with a positive center and orbiting electrons. He discovered the proton in 1919, in experiments on the disintegration of atomic nuclei. Much later, in 1932, the British physicist James Chadwick (1891— 1974) discovered a third subatomic particle, the electrically neutral neutron. 

The relationships to electromagnetic waves postulated by the German physicist Heinrich Rudoph Hertz led to the work of the English physicist Sir Joseph John Thomson in 1897, which is often linked to the actual discovery of the electron [26]. The measurement of the e/m and m of the corpuscles called electrons by Thompson settled this controversy. Electrons were at least particles, but other studies suggested that they were also electromagnetic radiation. Thompson described his conclusions as follows ... 

Sir Joseph John Thomson, bom near Manchester, 1856. Professor, Cambridge. Nobel prize in physics 1906. Knighted 1908. Died Cambridge, 1940. 

English physicist Sir Joseph John Thomson, recipient of the 1906 Nobel Prize in physics, in recognition of the great merits of his theoretical and experimental investigations on the conduction of electricity by gases. ... 

In October 1817 Thomson was appointed Lecturer in Chemistry in the University of Glasgow on the recommendation of Sir Joseph Banks. At the instance of the Duke of Montrose a Regius Professorship of Chemistry was instituted by George III, and Thomson, as the first incumbent, took up the appointment on 17 March 1818, with an annual salary of ()5o. Thomson s devotion to pure research in the first ten years of his professorship is noteworthy in view of the salary and the opportunities he had of doing more remunerative work. He had no laboratory until the summer of 1818 it was a... 

The idea that there are electric particles in substances was proposed, as a hypothesis, by G. Johnstone Stoney, an English scientist. Stoney knew that substances can be decomposed by an electric current —for example, water can be decomposed into hydrogen and oxygen in this way. He also knew that Michael Faraday had found that a definite amount of electricity is needed to liberate a certain amount of an element from one of its compounds. (The experiment carried out by Faraday will be discussed in Chapter 11.) In 1874, after thinking about these facts, Stoney stated that they indicate that electricity e.xists in discrete units, and that these units are associated with atoms. In 1891 he suggested the name electron for his postulated unit of electricity. The discovery of the electron by experiment was made in 1897 by Sir Joseph John Thomson (1856-1940), in Cambridge University, England. ... 

English physicist Sir Joseph John Thomson introduces the concept of electromagnetic mass. 

FIGURE 9.7 Sir Joseph John Thomson (1856 1940). Thomson is usually credited as the discoverer of the electron, although many people contributed to its identification as a basic building block of matter. Seven of his research assistants, who were also heavily involved in understanding the structure of matter, would eventually win Nobel Prizes. 

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