Re: REFRACTION - REFLECTION

["Dewey Dykstra, Jr." <dykstrad@bsumail.idbsu.edu>]

> Refraction is fundamentally a *wave* behavior and, as such, any analogy using
> particle-type models such as lawn mowers, tricycles, etc. have nothing to do
> with the effect.  If the messy details of the wave nature of the phenomenon
> are to be suppressed because they are too advanced for a lower level class
> then an appeal to Fermat's principle can be made.  This is because any
> wave propagation phenomena obeys Fermat's principle in the short wavelength
> limit and then the analysis can be done entirely in terms of rays.  In this
> case refraction is an automatic result of changing the speed of the rays
> in going from one fixed place to another fixed place while minimizing the
> time of travel for those rays.
>
> David Bowman
> dbowman@gtc.georgetown.ky.us

Actually, until one can measure the speed of light in different media
Newton had a pretty good particle base explanation of refraction.  Once we
could measure the speed of light in different media, we found that the
relative sizes of the speeds in Newton's model were backwards.

Dewey

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Dewey I. Dykstra, Jr.                   Phone: (208)385-3105
Professor of Physics                    Dept:  (208)385-3775
Department of Physics/MCF421/418        Fax: (208)385-4330
Boise State University                  dykstrad@bsumail.idbsu.edu
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Boise, ID 83725-1570                       novice piper

"Physical concepts are the free creations of the human mind and
are not, however it may seem, uniquely determined by the external
world."--A. Einstein in The Evolution of Physics with L. Infeld,
1938.
"Every [person's] world picture is and always remains a construct
of [their] mind and cannot be proved to have any other existence."
--E. Schrodinger in Mind and Matter, 1958.
"Don't mistake your watermelon for the universe."  --K. Amdahl in
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