J.J.+Thomson

J.J. Thomson ( **Joseph John Thomson)**

Biography: This is an image of a modern day version of J.J. Thomson's device that helped him prove his theory that an atom's matter was made up of cathode rays which where made up of corpuscle's (electrons). the device was made up of a glass tube, electrical wiring, and an energy source.
 * Joseph John Thomson **  (above) discovered a method for separating different kinds of atoms and molecules by the use of positive rays an idea developed by Aston, Dempster and others towards the discovery of many isotopes.
 * Born in Cheetham Hill on December 18, 1856.
 * Enrolled at Owens College, Manchester, in 1870
 * 1876 entered Trinity College
 * Became a Fellow of Trinity College in 1880
 * He married Miss Rose Paget on January 22,1890
 * Thomson remained a member of the College for the rest of his life
 * He worked with Professor J. H. Poynting on a four-volume textbook of physics
 * The textsbooks were called, //Properties of Matter// and in 1895 he produced //Elements of the Mathematical Theory of Electricity and Magnetism,// the 5th edition of which appeared in 1921.
 * 1896, Thomson visited America to give a course of four lectures,
 * The lectures talked about his current researches, at Princeton
 * The lectures were then called //Discharge of Electricity through Gases//
 * On his way back from America he discovered an original study of cathode rays,  which led to the discovery of the electron
 * Thomson returned to America in 1904 to deliver six lectures on electricity and matter at Yale University
 * The lectures talked about the structure of the atom.
 * He discovered a method for separating different kinds of atoms and molecules by the use of positive rays
 * J.J. Thomson ended up being a recipient of the Order of Merit and was knighted in 1908
 * He was elected Fellow of the Royal Society in 1884 and was President during 1916-1920
 * Thomson received the Royal and Hughes Medals in 1894 and 1902, and the Copley Medal in 1914
 * Thomson was awarded the Hodgkins Medal (Smithsonian Institute, Washington) in 1902; the Franklin Medal and Scott Medal (Philadelphia, 1923; the Franklin Medal and Scott Medal (Philadelphia), 1923; the Mascart Medal (Paris), 1927; the Dalton Medal (Manchester), 1931; and the Faraday Medal (Institute of Civil Engineers) in 1938
 * He was President of the British Association in 1909 (and of Section A in 1896 and 1931) and he held honorary doctorate degrees from the Universities of Oxford, Dublin, London, Victoria, Columbia, Cambridge, Durham, Birmingham, Göttingen, Leeds, Oslo, Sorbonne, Edinburgh, Reading, Princeton, Glasgow, Johns Hopkins, Aberdeen, Athens, Cracow and Philadelphia.
 * **He explained emission lines by saying electrons were trapped in a continuous blob of positive charge, like negative plums in a positive pudding.**
 * **He explained emission lines by saying electrons were trapped in a continuous blob of positive charge, like negative plums in a positive pudding.**

Evidence J.J. Thomson proved his theory that atoms were divisible by conducting three tests.

Test one: he investigated if the negatively charged rays could be separated from the rays by magnetizing them. he made a cathode ray tubes with slits on each side. these slits where connected to an electrometer. he then found out by magnetizing the rays and making then bend the electronic rays could not pass through the slits. because of this the electrometer registered little charge. Thomson then concluded that the negative charges were inseparable.

Test two: this test was to see if the rays could be deflected by an electric field. Thomson made a cathode ray tube that was vacuum sealed. this experiment showed that when under the influence of an electrifield the rays did bend. This showed that there are negative charges.

Test three: in this test Thomson measured the mass to charge ratio of the rays by measuring by how much they were deflected my a magnetic field and how much energy they carried with them. through this experament he found out that the rays were over one thousand times lower than a hydrogen ion. this showed that the particales were very light or they had a really high charge. this also suggested that the particales were a smaller part of the cathode ray.

his conclusion was that the cathode rays were made up of what he called corpuscles (A.K.A. electrons which were later thought up of). So if corpuscles make up a cathode ray and a cathode ray is part of the atom and if you can take a way the corpuscles from the ray then that means that the atom is divisible.

some cathode ray technology is still used today televisions by companies like Sony.