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100
Thales of Miletus
624-547 B.C. Thales was a Greek man who claimed that Water is the basic substance of our world. -
101
Anaxagoras and Empedocles
500-428 B.C., 484-424 B.C. Anaxagoras believed that changes in matter are due to different orders of "invisible" particles. Empedocles simplified those invisible particles into four seperate categories; Earth, Air, Fire, Water. -
102
Democritus
460 - 370 B.C. Democritus was the first greek to come up with the idea of the Atom. His belief is that the universe is made up of an almost infinite number of particles that differ from each other in almost every way possible. He called those particles "Atoms". -
Issac Newton
Issac Newton suggested that Atoms are held together by forces. He also said that "matter is formed of solid, massy impenetrable particles”. -
John Dalton
Dalton proposed that all matter is made up of atoms that can't be created or destroyed. He believes that there are 3 types of atoms; Simple (elements), Compound (simple molecules), and complex (complex molecules). -
George Johnstone Stoney
Georgeintroduced the idea of electrons and estimated the charge of a hydrogen atom. -
J.J. Thomson and Lord Kelvin
Joseph John Thomson and Kelvin created the first model for an atom. -
Robert Andrews Millikan
Millikan managed to measure the charge of an electron using a drop of oil. -
Ernest Rutherford
Ernest was the first man to split an atom. -
Henry Moseley
By measuring the wavelengths from x-rays of certain metals, Moseley was able to figure out how many positive charges there are in an atom. -
Neils Bohr
Neils published a book on his theory. His belief is that electrons orbit around the center of an atom. -
James Chadwick
James discovered the neutral charge of the atom which was previously unknown of.