Waves,Thoughts and Light

photo & video by marguerita

In the 1660s, Robert Hooke published a wave theory of light. Christiaan Huygens worked out his own wave theory of light in 1678, and published it in his Treatise on light in 1690. He proposed that light was emitted in all directions as a series of waves in a medium called the Luminiferous ether. As waves are not affected by gravity, it was assumed that they slowed down upon entering a denser medium.

Thomas Young's sketch of the two-slit experiment showing the diffraction of light. Young's experiments supported the theory that light consists of waves.

The wave theory predicted that light waves could interfere with each other like sound waves (as noted around 1800 by Thomas Young), and that light could be polarized, if it were a transverse wave. Young showed by means of a diffraction experiment that light behaved as waves. He also proposed that different colors were caused by different wavelengths of light, and explained color vision in terms of three-colored receptors in the eye.

Another supporter of the wave theory was Leonhard Euler. He argued in Nova theoria lucis et colorum (1746) that diffraction could more easily be explained by a wave theory.

Later, Augustin-Jean Fresnel independently worked out his own wave theory of light, and presented it to the Académie des Sciences in 1817. Simeon Denis Poisson added to Fresnel's mathematical work to produce a convincing argument in favour of the wave theory, helping to overturn Newton's corpuscular theory.

The weakness of the wave theory was that light waves, like sound waves, would need a medium for transmission.

A hypothetical substance called the luminiferous aether was proposed, but its existence was cast into strong doubt in the late nineteenth century by the Michelson-Morley experiment.

Newton's corpuscular theory implied that light would travel faster in a denser medium, while the wave theory of Huygens and others implied the opposite. At that time, the speed of light could not be measured accurately enough to decide which theory was correct. The first to make a sufficiently accurate measurement was Léon Foucault, in 1850.^[12] His result supported the wave theory, and the classical particle theory was finally abandoned.

Smithsonian News: Dashead and Acess/ Acquisitions

collage by marguerita
If a new study is any guide, the color red can make people’s work more accurate, but blue can make people more creative.“If you’re talking about wanting enhanced memory for something like proofreading skills, then a red color should be used,” said Juliet Zhu, an assistant professor of marketing at the university’s business school, who conducted the studies with Ravi Mehta, a doctoral student. For “a brainstorming session for a new product or coming up with a new solution to fight.Color Study Looks at Effects of Red and Blue - NYTimes.com

Unlike W. and Dick Cheney, who heroically resisted acknowledging their historically boneheaded mistakes, President Obama summoned a conga line of Anderson, Katie, Brian, Chris and Charlie to the Oval Office to do penance, over and over.

“I think I messed up. I screwed up,” he confessed to Couric.

He told the anchors that the man who helped make him president, Tom Daschle, had made “a serious mistake” by not paying taxes on a car and driver. (It should have been a harbinger of doom when Daschle began sporting those determined-to-be-hip round red glasses.)Op-Ed Columnist - Well, That Certainly Didn't Take Long - NYTimes.com

Noted.