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Traveling
with the Atom
Allegheny College |
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(compiled by Dr.Glen
E. Rodgers)
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| A photograph of Thomson's cathode ray tube showing the embedded electric plates that he used to divert the ray that found was composed of a beam of negatively charged electrons |
© Science Museum/Science & Society Picture Library |
| Thomson, working at the Cavendish Laboratory of Physics in Cambridge, determined in 1897 that cathode rays were beams of electrons. He also determined the mass to charge ratio of an electron by balancing the effect of electric and magnetic fields on these cathode rays. He proposed the "plum-pudding" model of the atom in which thousands of electrons were embedded in a massless cloud of electricity. Later he argued that the number of electrons in an atom was approximately equal to the atomic weight of that element. He was awarded the 1906 Nobel Prize in Physics. |
| The Discovery of the Electron |
| Science Museum (London) |
| Nobel Prize Webpage on Thomson |
| Interactive animation of the e/m experiment (The Science Museum) |
| The
Thomson Experiment Atom: the Incredible World |
| Figure of Thomson and his tube showing that cathode rays cast a shadow | Adapted from Figure VII-1, Biography of Physics, George Gamow, p 212 |
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| Full biographical information on Sacks' book Uncle Tungsten | p 244; 288 |
| Full biographical information on Asimov's Biographical Encyclopedia of Science and Technology, 2nd Ed. | pp 561-563 |
| Thomson's 1897 paper on cathode rays | The Cavendish Laboratory, 1874-1974, J. G. Crowther, Science History Publications, New York (1974). (Sometimes out of print but perhaps available from Amazon.com) |
| Leadership and Creativity - A History of the Cavendish Laboratory, 1871-1919 (ARCHIMEDES Volume 5) New Studies in the History and Philosophy of Science, by Dong Won Kim (scheduled to be available March, 2002) |
| The Cavendish Laboratory of Physics. The "old Cavendish" was (on Free School Lane) but it now houses other departments (1,2,3) | Free School Lane (near King's College) in Cambridge, England. A plaque* explaining the electron was discovered here by Thomson is still available |
| The Museum at the Cavendish Laboratory. A small but wonderfully engaging museum on the first floor of the Bragg building has a number of exhibits including Thomson's original e/m tube and biographical information* (1,2,3) | The Cavendish Laboratory
Madingley Road Cambridge, England CB3 0HE (Need to make arrangements in advance to see the small museum.) |
Link to Dr. Rodgers' Scientific/Historical Site on the Cavendish Laboratory.
| Scientific Historical Traveling | Rodgers Home Page |
