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Old 11-01-2014, 08:57 AM   #5
NN5I
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Quote:
Originally Posted by wa8yxm View Post
Well, we could argue semantics all day but that dispersion is caused because the different frequencies are slowed at different rates. else they would all refract the same.
My apology, YXM. I meant no offense. I only meant to point out that dispersion and refraction are separate phenomena; neither implies the other. Refraction is almost always accompanied by at least some dispersion, as you imply; but dispersion often occurs without refraction. The dispersion that gives rise to rainbow colors on oil-filmed water, for example, is a result of diffraction, not refraction; and most of the iridescent colors on insect wings also are associated with diffraction and not with refraction.

The rainbow is not yet fully understood, despite centuries of scientific inquiry; fairly recent articles in Scientific American suggest that it may be caused by diffractive dispersion as well as by refractive dispersion.
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