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100
Thales of Miletus
585 B.C. Thales noticed that when you rub fabric together, it creates static electricity. This paved the way for future discoveries. -
100
Leucippus
500 B.C. Leucippus came up with the idea that everything is made up of something. -
100
Democritus
around 400 B.C. Democritus created the first atomic model. He was the first to think of the atom. -
100
Aristotle
Around 400 B.C. Aristotle opposed Democritus' theory. He said there were only four elements, earth, fire, air, and water. -
Isaac Newton
Newton discovered the 3 laws of motion which helped scientists make further discoveries. -
John Dalton
Dalton created "Dalton's Atomic Theory" which says,
1. All matter is made up of atoms (true). These atoms are indivisible (false).
2. All atoms of the same element are the same (false). Atoms of different elements are different (true).
3.Atoms combine to make compounds (true).
4. Atoms are rearranged - not created or destroyed - in a chemical reaction (true). -
J.J. Thompson
Thompson discovered the electron using the cathode ray after others thought there were particles that made up the atom. He created the plum pudding model. -
Ernest Rutherford
Rutherford discovered that atoms have positive charge in a small, but dense nucleus. He did this through the "gold foil" experiment. -
Niels Bohr
Bohr discovered electrons travel on rings (energy levels). The more rings, the higher the energy level. He also discovered electrons can move from ring to ring, but it takes energy. -
Erwin Schrodinger
Schrodinger described a cloud-like region around the nucleus of an atom where an electron is likey to be found. -
John Chadwick
Chadwick discovered the neutron and the difference it made in the mass of an atom.
