Editing Cathode ray (section)

===Discovery of the electron===
[[File:JJThomsonGasDischargeTubeElectronCavendishLab2013-08-29-17-11-41.jpg|thumb|upright=1.3|J. J, Thomson's electric deflection tube, in which he showed that a beam of cathode rays was bent by an electric field like matter particles. The cathode is on R. The electron beam is accelerated passing through the cylindrical high voltage anode (''center''), bent by a voltage on the deflection plates (''center L''), and strikes the back wall of the tube causing a luminous glow.]]   
At this time, atoms were the smallest particles known, and were believed to be indivisible. What carried electric currents was a mystery. During the last quarter of the 19th century, many historic experiments were done with Crookes tubes to determine what cathode rays were. There were two theories. Crookes and [[Arthur Schuster]] believed they were particles of "radiant matter," that is, electrically charged atoms. German scientists Eilhard Wiedemann, [[Heinrich Hertz]] and Goldstein believed they were "aether waves", some new form of [[electromagnetic radiation]], and were separate from what carried the electric current through the tube.

The debate was resolved in 1897 when [[J. J. Thomson]] measured the mass of cathode rays, showing they were made of particles, but were around 1800 times lighter than the lightest atom, [[hydrogen]]. Therefore, they were not atoms, but a new particle, the first ''[[subatomic particle|subatomic]]'' particle to be discovered, which he originally called "''corpuscle''" but was later named ''electron'', after particles postulated by [[George Johnstone Stoney]] in 1874. He also showed they were identical with particles given off by [[Photoelectric effect|photoelectric]] and radioactive materials.<ref name="Thomson1">{{cite journal
  | last = Thomson
  | first = J. J.
  | title = On bodies smaller than atoms
  | journal = The Popular Science Monthly
  | pages = 323–335
  | publisher = Bonnier Corp.
  |date=August 1901| url = https://books.google.com/books?id=3CMDAAAAMBAJ&pg=PA323
  | access-date = 2009-06-21}}</ref> It was quickly recognized that they are the particles that carry electric currents in metal wires, and carry the negative electric charge of the atom.

Thomson was given the 1906 [[Nobel Prize in Physics]] for this work. [[Philipp Lenard]] also contributed a great deal to cathode-ray theory, winning the Nobel Prize in 1905 for his research on cathode rays and their properties.