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Joseph John Thomson

( English physicist, Nobel Prize in Physics, 1906)

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Biography Joseph John Thomson
December 18, 1856, Mr.. - August 30, 1940
English physicist Joseph John Thomson was born in Chithem Hill, a suburb of Manchester, the son of Joseph James and Emma (nee Suindells) Thomson. As the father, the bookseller, wanted the boy to become an engineer, in the age of fourteen was sent to Owens College (now University of Manchester). But two years later his father died, leaving his son without the means. Nevertheless, he continued his education with the financial support of his mother and a scholarship fund.
. Owens College, played an important role in the career of TV, because there was a well-appointed faculty and unlike most colleges at that time gave courses of Experimental Physics
. Having at Owens in 1876, Mr.. the title of engineer, T. Trinitikolledzh enrolled at the University of Cambridge. Here he studied mathematics and its applications to problems of theoretical physics. Bachelor's Degree in mathematics, he received in 1880. The following year he was elected a member of the Academic Council Trinitikolledzha and began working at the Cavendish Laboratory in Cambridge.
In 1884, Mr.. Dzh.U. Stratton, successor Jamie Clerk Maxwell on the post of professor of experimental physics and director of the Cavendish Laboratory, retired. T. took this position, despite the fact that he was only twenty-seven years and he still has not made any significant progress in experimental physics. However, it is valued as a Mathematics and Physics, he is actively applied Maxwell's theory of electromagnetism that considered adequate for its recommendations on this post.
Upon assuming his new duties in the laboratory, T. decided that the main focus of his research should be the study of electrical conductivity of gases. He was particularly interested in the effects due to the passage of an electric discharge between electrodes placed at opposite ends of the glass tube from which nearly all the air is exhausted. Several researchers, among them the English physicist William Crookes, drew attention to a curious phenomenon occurring in the gas-discharge tubes. When the gas becomes sufficiently rarefied, . glass walls of the tube, . located at the end, . opposite to the cathode (negative electrode), . begin to fluoresce green light, . what, . likely, . occurred under the influence of radiation, . occurring at the cathode.,
. Cathode rays have caused in the scientific community an enormous interest and respect their nature the most divergent views were expressed
. British physics for the most part believed that these rays are a stream of charged particles. In contrast, German scientists have for the most part inclined to believe that they are the disturbances - perhaps oscillations or currents - in a kind of hypothetical weightless environment in which they felt affected by this radiation. From this perspective, the cathode rays are a kind of high-frequency electromagnetic waves, similar to ultraviolet light. The Germans referred to the experiments of Heinrich Hertz, who is said to have discovered that cathode rays, departing under the influence of the magnetic field, remain insensitive to the strong electric field. It was assumed that this refutes the opinion that the cathode rays - a stream of charged particles, because the electric field always has an impact on the trajectory of such particles. Even if it was true, nevertheless, experimental arguments German scientists were not entirely convincing.
Investigations of cathode rays and related phenomena came to life in connection with the discovery by Wilhelm Roentgen in 1895. ray. Incidentally, this form of radiation, which has not previously suspected, may also occur in gas-discharge tubes (but not at the cathode and the anode). Soon, TV, working with Ernest Rutherford discovered that irradiation of gases by X-rays greatly increases their electrical conductivity. X-rays ionize the gases, ie. They turned the gas atoms into ions, which in contrast to the atoms are charged and, therefore, serve as good carriers of current. T. showed that the resulting conductance is somewhat similar to the ionic conductivity of the electrolysis in the solution.
. After completing his students with a very fruitful study of conduction in gases, T., emboldened by success, Grechischev unresolved issue, which took him many years, namely the composition of the cathode rays
. Like others of his British colleagues, he was convinced of the corpuscular nature of cathode rays, believing that it could be fast ions or other electrified particles emitted from the cathode. Repeating the experiments of Hertz, T. showed that in fact the cathode rays are deflected by electric fields. (A negative result from Hertz was the fact that its gas-discharge tubes was too much residual gas.) T. noted later that 'the deviation of cathode rays by electric forces become quite distinct, and its direction indicated that the components of cathode ray particles carrying a negative charge. This result resolves the contradiction between the effects of electric and magnetic forces on the cathode particles. But he is much more important. Here there is a method of measuring the velocity of the particles v, as well as e / m, where m - particle mass, and e - of its electric charge '.
The method proposed by the TA, was very simple. First, a beam of cathode rays deflected by means of an electric field, and then using a magnetic field it rejected an equal amount in the opposite direction, so that in the end beam once again straighten up. Using this experimental technique has become possible to derive simple equations, of which, knowing the intensity of the two fields, easily defined as v, and e / m.
. Thus found value of e / m for cathode 'corpuscles' (as they are called TA) was 1000 times greater than the corresponding values for hydrogen ion (we now know that the actual ratio is close to 1800:1)
. Hydrogen among all the elements have the highest charge to mass ratio. If, as assumed, T. corpuscles carrying the same charge as the hydrogen ion ( 'unit' electric charge), he opened a new entity that is 1000 times lighter than the simplest atom.
This suspicion was confirmed when T. with an instrument invented CH.T. R. Wilson, managed to measure the value of e and show that it really is the corresponding value for the hydrogen ion. He found further that the ratio of charge to mass ratio for the corpuscles of the cathode rays do not depend on what gas is in a discharge tube and the material from which the electrodes are made. Moreover, the particles with the same ratio of e / m could be separated from coal during heating and from metals exposed to ultraviolet rays. Hence, he concluded that 'the atom - not the last limit of divisibility of matter, we can move forward - to the corpuscles, and the corpuscular phase is the same, regardless of the source of its origin ... It is likely, is an integral part of all varieties of matter at very different circumstances, so it seems quite natural to consider corpuscle as one of the blocks, of which built the atom '.
T. went further and proposed a model of the atom, consistent with its opening. At the beginning of XX century. He hypothesized that the atom is a fuzzy area, carrying a positive electric charge, which distributed negatively charged electrons (as in the end it became known as corpuscles). This model, although it was soon superseded by the nuclear model of the atom proposed by Rutherford, a number of features of value to scholars of that time and to encourage their quest.
T. received in 1906. Nobel Prize in Physics "in recognition of his outstanding contributions in the field of theoretical and experimental studies of the conduction of electricity in gases'. At the presentation ceremony winner JP. Klason, a member of the Royal Swedish Academy of Sciences, congratulated the T. the fact that he 'gave the world several major works, allowing natural philosophers of our time to undertake new research in new directions'. Showed that the atom is not the most recent indivisible particle of matter, as long believed, T. in fact opened the door to a new era of physical science.
Between 1906 and 1914. the T. started the second and last great period of experimental activity. He studied the channel beams, which move toward the cathode in a discharge tube. Although Wilhelm Wien had already shown that the channel rays are a stream of positively charged particles, T. colleagues have shed light on their characteristics, identified different types of atoms and atomic groups in these rays. In their experiments T. demonstrated a completely new way of separation of atoms, showing that some atomic
groups such as CH, CH2 and CH3, may exist, although under normal conditions of their existence is unstable. Of great importance is the fact that he was able to find that the samples contain an inert gas of neon atoms with two different atomic weights. The opening of these isotopes has played an important role in understanding the nature of heavy radioactive elements such as radium and uranium.
During the First World War T. worked in the Office of Research and Inventions, and was an adviser to the government. In 1918, Mr.. he led Trinitikolledzh. A year later, Rutherford succeeded him as professor of experimental physics and director of the Cavendish Laboratory.
After 1919. activity T. reduced duties as head of Trinity College, additional research in the Cavendish Laboratory and the best value for money. He liked to work in the garden, and he frequently make long trips in search of unusual plants.
Thomson married Rose Paget in 1890, they had a son and daughter. His son, JP. Thomson won the Nobel Prize in Physics for 1937. T. died August 30, 1940, Mr.. and was buried in Westminster Abbey in London.
T. had an impact on physics, not only the results of his brilliant experimental studies, but also as an excellent teacher and a wonderful leader of the Cavendish Laboratory. Attracted to these qualities, hundreds of the most talented young physicists from around the world chose the place of learning Cambridge. Of those who worked in the Cavendish led T., seven were in their time Nobel Peace Prize.
In addition to the Nobel Prize T. received many other awards, among which you can specify the coin: the Crown (1894), Hughes (1902) and Copley (1914), awarded the Royal Society. He was president of the Royal Society of London in 1915. and he was ennobled in 1908


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