discovered that atoms must exist based on the relationship between pressure and temperature.
Discovered that oxygen is present in the air
discovered the law of conservation
discovered the law of constant
created the atomic theory that we still use today
used cathode ray tubes to help discover the electron
Invented the Crookes tube in 1875 which showed evidence of electron streams
Used cathode ray tubes to help discover electrons in 1897
discovered the elements radium and polonium in 1898
Helped discover the atomic nucleus in 1908
Confirmed that all matter was comprised of atoms
discovered the charge of an electron in 1908
overturned Thomson's model of the atom in 1911 with the gold foil experiment.
discovered the neutron in 1932.