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350
Aristotle
Aristotle created methods to help gather facts. He did not agree with Democritus' theory. Aristotle thought that all matter was made out of the four elements: fire, water, earth, and wind. -
400
Democritus
Democritus was a greek physical philospopher that discovered the atom. He then created the first atomic model. Democritus believed that atoms were invisible and indestuctible. His model was in the shape of a sphere. Democritus was unaware of the many parts of the atom. -
Antoine Lavoisier
Antoine proved that mass can not be created or destroyed. This would later be known as The Conservation of Mass. Antoine also explained the myteries of fire. -
John Dalton
John Dalton's theory was that all matter was made up of atoms, atoms of the same element were identical, and atoms of different elements have different properties and weights. He also thought that atoms make up compounds in simple ratios. -
Creation of dynamite
Alfred Nobel created the first dynamite. -
Henri Becquerel
Henri Becquerel was a french physicist that conducted an experiment that led to the discovery of natural radioactivity. -
J.J. Thomson
Thomson discovered that the charge to mass ratio depended on filling in the tube when he studied the positive rays in the cathode ray tube. The largest charge to mass ratio happened when hydrogen was the filling gas. This was later identified as the proton. -
Max Planck
Max Planck suggested the idea of quantization to explain how a hot, glowing object gave off light. -
Hantaro Nagaoka
Hantaro proposed an atomic model called the Saturnian Model to desribe the structure of an atom. -
Ernerst Rutherford
Rutherford proposed that an atom was mostly empty space with a concentrated nucleus in the middle and electrons orbiting around it in unfixed orbits. He proposed after conducting the gold foil experiment. -
Neils Bohr
Niels Bohr proposed an atomic structure theory that stated the outer orbit of an atom could hold more electrons than the inner orbit. -
Henry Moseley
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Louis de Broglie
Louis was a french quantum physicist that created the theory of particle-wave duality. This theory explained how atoms molecules, and protons behave. Louis' theory inspired Erwin Schrodinger in the formulation of wave mechanics. -
Erwin Schrodinger
Schrodinger furthered Bohr's model and stated that rather than electrons being distributed within an electron configuration of shells and energy levels, they are arranged in orbitals within electron clouds. -
James Chadwick
James Chadwick proved the existence of neutrons by bouncing alpha particles off of them and examining them. -
Bombing of Nagasaki
The United States had dropped an atomic bomb in Nagasaki, Japan. The bomb was named "fat man". The bomb killed 70,000 people. -
Chernobyl
The nuclear disaster exposed millions and millions of people to the radioactive isotopes.
