Re: Another student question

[brian whatcott <inet@intellisys.net>]

At 15:47 11/13/97 -0700, you wrote:
> In optics, when a ray of light changes media its frequency is said to be
> unaffected, but its wavelength is changed to reflect the change in velocity 
> in the new medium and /nu = /lambda * f.
>
> Why is frequency unchanged and wavelength changed? ... I told my 
> students I would pose this question to my peers.  So here it is.
>
> Dan M
Not wishing to provoke any peer-pressure, I'll abjure that tag,
but get down and dirty with an irresistable metaphor drawing on the
corpuscular theory of light (very suitable from the lips of a crepuscular 
source like me....)

I throw an orange per second (frequency = 1Hz) through the air.
 I aim them at a tall glass jar full of oil.
Oil is lighter than water and orange pith so they sink 
( do they? Didn't check this...)

As they sink down the jar, I count the number of oranges passing a point.
There is still just one per second.
 But now, instead of a velocity of 5 m/s they sink at 1 m/s ( hypothetically)
and their wavelength has shrunk from 5 meters to one meter....

Sincerely

brian whatcott <inet@intellisys.net>
Altus OK