jan 1, 1920 - Albert A. Michelson's Measurements
Description:
Michelson placed two mirrors on top of two mountains (in California) and measured the distance between the two mirrors (35.4 km). He sent a light beam from one mirror to the other. Using accurate timing devices, he carefully calculated the speed of light in the Earth's atmosphere which is 299 798 km/s.
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Gr. 8 Science Unit C Section 1.0 Timeline
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