-
340
Aristotle
Note- Date is BC
Aristotle, Greece - provided the method of gathering scientific facts, which proved as the basis for all scientific work. -
440
Democritus
Note- date is in BC
Greece - stated that all matter is made up of atoms. He also stated that atoms are eternal and invisible and so small that they can’t be divided, and they entirely fill up the space they’re in. -
Robert Boyle
He measured relationships between volume and pressure of gasses. From his expiraments he concluded that gasses are made up of tiny particles that group together to make different substances. -
Antoine-Laurent Lavoisier
Lavoisier (1777), France - provided the formula for the conservation of matter in chemical reactions, and also distinguished between an element and a compound. -
John Dalton
John Dalton (1803), England - formed the atomic theory, which states that all matter is composed of tiny, indestructible particles called atoms that are all alike and have the same atomic weight. -
J.J Thomson
J.J Thomson (1898), England - discovered the electron and developed the plum-pudding model of the atom. -
The Curies
The Curies (1898), France - discovered radium and polonium when they started to investigate radioactive substances -
Hantaro Nagaoka
In 1904, Hantaro Nagaoka developed an early but incorrect planetary model of the atom. He based his model of the atom around the rings of the planet saturn. however his model was not created properly. He explained that the rings are held there due to its massive orbit. although this model was wrong it still allowed for the discovery of the atoms rings. -
Robert Millikan
Robert Millikan (1908), USA - found out the electric charge of the electron -
Ernest Rutherford
Ernest Rutherford (1909), England - used the results of his gold-foil experiment to state that all the mass of an atom were in a small positively-charged ball at the center of the atom. -
James Chadwick
James Chadwick (1931), England - discovered the neutrally-charged neutron.
