Democritus was an Ancient Greek philosopher. He is primarily known today for his formulation of the atomic theory. Democritus reffend to atoms as "that which cannot be cut".
Aristotle refuted Democritus and believed very strongly that the world was made up of four elements: Earth, Air, Water, Fire. This "theory" led to 2000 years of nonsense science exploration.
Robert Boyle discovered the functions of gases and their behaviors. This shed light on the differences between volume and pressure.
In 1733, Joseph Priestley came up with th thought that idea that air was an indivisible element. After testing this theory, he discovered instead that air is combination of gases when he isolated oxygen. He went on to discover seven other discreet gases.
Anton is referred to as the Father of Modern Chemistry. He mainly depended on quantitative observations to make the conclusions he discovered. Voisier also disproved the Phlogiston theory when having proven that oxygen causes combustion. He also discovered the Law of Conservation of Mass.
Benjamin Franklin discovered positive and negative charges in electricity. From this discovery, he became aware that like charges repel and opposite charges attract.
Joseph Louis Proust discovered the Law of Definite Proportions. This law was able to conclude that a chemical compound always contains the same amount of element to mass.
John Dalton came up with the Atomic Theory of Matter. This theory stated that atoms are indestructible and indivisible. Also, all atoms are identical, though they may have different weights and properties.
Ernest Rutherford classified the levels of radium. Alpha was the slowest level. Beta was a level up, making it fast. The last level is gamma. It is very fast.
William Crookes formed the Cathode Ray Tube (CRT). A CRT is a glass tube that contains no matter. Its main purpose is to identify radiation steaming from the battery using neon paint. Crookes then put a wheel in the CRT. The wheel spun, indicating the Ray had mass.
Thomson later continued discoveries with the CRT. After many explorations, he deducted that the Ray was made of negative particles. He proceeded to name them electrons.
Becquerel discovered radioactivity in Uraium Oar. It allowed scientist to safely observe Uranian.
Marie and Pierre discovered polonium and radium from uranium ores. They isolated it because of the radioactivity. This gave scientist the idea that something inside the atom gave it it's own identity.
Millikan calculated the mass and charge of an electron. The experiments to deduct this took place from 1908 to 1917. It was called the Millikan Oil Drop.
Chadwick proved that other subatomic particles had no charge. He named them neutrons, to display that they are neutral.