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500
Aristotle
Aristotle thought that all matter was made of earth,air,water,and fire. This created the platform for future scientists and philosophers. -
500
Democritus
Gave the idea that atoms are invisible -
Period: 500 to
Timespan
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John Daltons
John Dalton proposed five ideas to the world of science. 1, All matter is made of invisible particals,2.All atoms of the same element are the same,3 Atoms of different elements are different,4 Elements combine together insmall whole number ratios,5 Atoms are small hard spheres -
Henri Becquerel
discoverd that rays emitted by uranium differ from an x-ray. They also could not be detected by electro magnetic fields. -
J.J Thomson
He discovered the electron. He discoverd the electron by using the plum pudding model. -
Ernest Rutherford
Rutherford used a gold foil experiment. He shot a positively charged beam of particals through a gold foil sheet. If the particals were soft it would conclude J.J Thompsons plum pudding model was true. -
Robert Millikan
Found the charge and mass of the electron. Millikan used his oil drop experiment. -
Niels Bohr
Bohr proposed the idea that electrons travel around the nucleous in a definite path. -
James Chadwick
James Chadwick discoverd the neutron. -
Marie & Pierre Curie
Discovered radioactivity and the elements Polonium and Radium. -
Quantum Model
The current day model of an atom is based on the quantum theory.
