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400 BCE
Democritus
Democritus was a Greek mathematician, astronomer, and also studies physics. He worked with Leucippus in a majority of his works. He was known to be very materialistic, and believed that everything was the result of natural law. He describes that matter is composed of tiny particles. They were known to be indivisable or uncuttable. Also said that atoms will always be in motion. -
John Dalton
John Dalton states that elements exist in packs of matter. He created the first chart for atomic weight and ratios. -
Eugene Goldstein
In 1886, Eugene found that there is a positive charge in matter. He found this using Cathode rays. -
JJ Thompson
Found that the mass of the cathode rays were 100x lighter than the smaleest known particle, this proposing that the rays were packed electrons. He also in 1904, proposed the plum pudding model which included electrons. -
Rutherford
Also known as the Father of Nuclear Physics, Rutherford developed the structure if the atom called scattering. He did an experiment with gold foil where he shot a positive charge at the foil. While some went right through the foil, some bounced of. This was the first sighting of an atomic nucleus. -
Bohr
Bohr created a model that showed Electrons are small and negatively charged particles that orbit around the nucleus, Protons are in the Nucleus, and that for certain elements light is absorbed or emitted.
