Saturday, June 5, 2010

SCIENTISTS

Willebrordus Snellius -

 Refraction of light ©



Willebrord Snel van Roijen (1580-1626) was a distinguished Dutch mathematician, physicist and astronomer. He used the latin name "Willebrordus Snellius" as his scientific alias. Snel (written with one l) is most famous for his discovery in 1621 of the law of refraction, generally referred to as "Snel's law".
Phenomena such as "the broken stick", focusing of light by a lens, imaging by a lens, prismatic colours and the rainbow are all based on the refraction of light when it passes from one medium to another, provided that the optical density of both media is different.
The downloadable slideseries (3.7 Mb) shows that the refractive index of various security features defines their optical behaviour. (slideseries expanded per 21 July 2007).
Download: Refraction.pps

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