A VERY BRIEF HISTORY OF TIME
By: Brian Williams

What are “things” made of?
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Aristotle- four elements
Earth, Water, Air, and Fire
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Atomic Theory- All things are made up of small, indivisible pieces of matter called atoms.
Proposed by John Dalton in the early 1800’s.

What makes “matter” move?
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Pre-Newton- Science was descriptive, based on observation
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Isaac Newton- Provided qualitative descriptions of motion, developed three laws of motion; the father of “Classical
Mechanics”

What is matter REALLY made of?
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Electron- Discovered in 1897 by J.J. Thomson, using cathode rays. Thomson was able to measure e/m, and thus deduce the mass of the electron.
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Nucleus- Discovered in 1910 by Ernest Rutherford while doing experiments with alpha particles.
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Bohr Model- negatively charged electrons orbit a small, positively charged nucleus, the atom consists of mostly empty space.

What’s the problem?
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The Bohr Model wasn’t consistent with classical mechanics.
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In fact, there was no way for classical mechanics to explain the atom, so a new theory was required!