A Brief History of Light ( by Efthymios Kallos) (edited by Mrs. John & Mr. Lefebvre)
| The struggle to understand light
The main issue of the early theories of light was to resolve whether it was a wave or a particle, and this proved to be a difficult task. It started as a particle from the ancient Greeks, then it became a wave with Huygens, then Newton suggested a particle theory again, then Fresnel and others suggested a wave theory again, then Einstein suggested a particle theory once more, until finally Quantum Mechanics settled it down: it is both a wave and a particle! Now everyone is happy except for the fact that no one understands what that really means...Huygens vs. NewtonChristian Huygens was born in 1629, while Isaac Newton was born in 1643. Huygens was the first to build a mechanical clock, making use of Galileo's realization that a swinging pendulum kept a regular rhythm. He built the first of this type of clock at the age of 28, and a year later his design was used in all of the major churches in Holland. At 45 he built the first watch, winning the race from Hooke, Newton's great rival. At 1690, when he was 61, he fully published his wave theory of light, suggesting that it propagates as a disturbance (spherical pressure wave) in the air. One of the most important predictions of his theory was that light should propagate slower in a denser medium, something that was not experimentally confirmed until the next century.Newton was working on his particle theory of light at the same time as Huygens. Due to the enormous power of his theory of gravity, he was already considered a grandmaster of science. Therefore his particle theory of light won the battle with Huygens' theory of waves and was widely accepted in the scientific community. He assumed that light consisted of particles, which he called corpuscles. In 1669, in a series of lectures he delivered in Cambridge, he explained his theory of colors and specifically how a prism alters the...
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