INVESTIGATING NEW RAYS
- Dalton, in 1808 proposed that matter is made of atoms. All substances were either made of single atoms or combinations of atoms (molecules).
- He thought that atoms were indivisible.
- In the 19th century, experiments showed that atoms were divisible. As a result, new particles and forces were found.
CATHODE RAYS
- Geissler in the 19th century, Invented a new vacuum pump.
- He produced discharges of electricity in evacuated tubes of varying shape. He also produced difference colors of discharge by placing different gases in the tubes.
GAS DISCHARGE TUBE - A tube that allows an electric current to pass through a gas at low pressure.
ELECTRODES - Metal plates sealed in the ends of a gas discharge tube. (+ is the anode and - is the cathode.)
- When air is pumped out of the tube, the discharge across an induction coil stops, and the electrodes in the tube are connected by one or more violet streamers.