Physics 150 Fall 2003
Lect. 12.
Summary of Classical Physics
Start the Revolutions of Modern Physics
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Summary
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Classical physics : completed by 1880
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Paradigm for understanding nature
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Primitive quantities
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Time - the same for everyone, measured in units set by standard clocks
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Space - three dimensions - the same for everyone, measured in units set by by standard meters
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Mass - three dimensions - the same for everyone, measured in units set by by standard kilogram
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Motion of bodies described by Newton's laws
electromagnetism descrbed by Maxwell's laws
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Is Physics dead? Nothing left to do? What does a scientist do?
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Test the laws. Nothing is ever taken as a final truth.
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Design the key experiment that makes the test
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Michelson, Morley experiment
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Done in Cleveland, Ohio in 1887
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Does the earth move with respect to the "ether"?
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Used interference of light to make a very sensitive experiment
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Result: Light appears to have the same speed in all directions,
independent of the motion of the earth
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A fundamental failure of classical physics
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What does this mean? -- Next Time
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Next Time: Special Theory of Relativity: Einstein
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Read for Next Time: Lightman, Chapt. 3, March, Chapt. 9