🚀 go-pugleaf

On Sun, 16 Oct 1994, Judy Ng wrote:

> Each year in the light and optics unit, there is at least one
> student asked how the speed of light 3* 10^8 m/s is measured or
> obtained.  For three years I tried to show the class, but ONLY
> VERY FEW students can follow the presentation.  It became a
> lost cause and a waste of time.  Does any one has any easy,
> simpler way or method (less mathematical and easier to
> understand)  to answer this question.
>
> judy Ng
> -- jng@pen.k12.va.us
>
The 7th edition of PSSC Physics addresses students' difficulty in
following the rotating mirror method of determining the speed of light
(if this is the method you are referring to!) by preceeding it with a lab
dealing with the determination of the speed of sound using echoes from a
distant wall.  This gives students the idea that they can find speed by
taking twice the distance to the wall divided by the time interval
between the original sound and the echo.  This idea then carries over to
the mirror reflection method used by Michelson.  Hope this helps!

Bob Stair
AAPT Physics Teaching Resource Agent (PTRA-PLUS)
Evergreen High School
Evergreen, CO 80439
303-674-3341
bobstair@csn.org