Re: [Phys-l] light clock relativity experiment

["Richard Tarara" <rbtarara@sprynet.com>]

----- Original Message ----- 
From: "Fink Trevor M" <tmfink@ilstu.edu>

Subject: Re: [Phys-l] light clock relativity experiment


The reason for my inquiry is that I was taught to believe that nothing
changes the velocity of light other than reflection, refraction, and change
in medium.  None of the previous s
> eem to apply to this train (other than being reflected to travel at 180
> degrees from its former vector as it reaches the top and bottom of the
> train)

JD has problems with "time dilation" (I don't) but MY pet peeve is with the
notion that light moves at different velocities in different media.  The
EFFECTIVE speed is different, but (as I understand it), light itself always
moves at what we call the speed of light.  Through the process of being
absorbed, reradiated, absorbed, reradiated, the transit time through
different materials varies, but from one radiation to the next absorption
the speed is 3x10^8 m/s.  Many intro texts don't really emphasize this
(Hecht's does--but now seems to be going out of print).

Rick

Richard W. Tarara
Professor of Physics
Department of Chemistry & Physics
Saint Mary's College
Notre Dame, IN 46556