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430
Leucippus
B.C.E. He was the first person to develop the theory of atomism, "the idea that everything is composed entirely of various imperishable, indivisible elements called atoms" -
460
Democritus
B.C.E. Expanded on Leucippus' theory of the atom. His discoveries are still used today. -
Dalton
Dalton found the atomic theory of matter, adding to it the idea that different elements had different characteristic atomic weights. Also in his work is the earliest depictions of the molecular structure, in which the atoms in a molecule are arranged in space in a specific fashion. -
Revolutionary War begins
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U.S. Civil War begins
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Thomson
Discovered the electron, and theorized the design of an atom; the protons in the center with the electrons flying around a great distance from them. -
Planck
He originated quantum theory. -
Period: to
Scientific Timeline
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Millikan
He determined the unit charge of an electron. This allowed for the calculation of electrons, and positively charged atoms. -
Rutherford
Described the atom as having orbiting electrons around a cluster of protons. He said that most of the mass is in the conter, and the rest of the atom is mostly empty space. -
Bohr
Applied quantum theory to previous theorys about the setup of am atom. His assiumptions led to calculations of energy levels in electron orbits. -
Schrodinger
Determined the wave/particle duality of nature. -
Louis de Broglie
Broglie discovered the wave nature of electrons. -
Heisenberg
Came up with the "Heisenberg Uncertainty principle," which states that no experiment canmeasure the momentum and the position of a particle at the same time. -
Chadwick
Proved the existence of the neutron. -
Hawaii became the 50th state
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Korean War begins
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Chernobyl
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Empedocles
B.C.E. Discovered air as a seperate substance. -
Plato
B.C.E. Plato said that the atoms that make up everything are made of right triengles. -
Aristotle
B.C.E. Theorized that all things were made up of a potential, their matter, and their reality (or form).
