J.J Thomson was a physicist who is credited for discovering the
electron. He used his research on cathode ray tube technology in this
discovery.
1. Nearly Empty tube (Air has been sucked out)
2. An electric charge is passed through the tube. Travels from cathode to
anode
3. The charge is invisible, so to see where it traveled a fluorescent screen is
placed at back of tube. Where the beam hits, a
dot will appear on the screen. You could also use a
fluorescent gas and the whole tube will light up.
4. This beam will always travel straight if not
interfered with.
5. The deflection coils each have a specific charge.
One is positive and the other is negative.
6. Thomson showed (as in the diagram above) that
the charge would deflect away from the negative
coil. He then stated that this charge was thus a
negative charge.