The index of refraction is not completely independent of
Light of higher frequency is
bent (or refracted) more than a lower frequency.
The raindrop and the light ray
Finally, when light hits a surface with a different index
of refraction, some light is reflected.
2 points of refraction, 1 point of reflection.
Light comes in from the left.
At the first boundary, different colors head off in slightly
At the back surface (right), some light is reflected.
Now when it comes out the front surface (left), the different
colors are refracted again. (Since this surface is
not parallel to the input surface, the two light rays shown come out at
slightly different angles. This difference in angles gives rise to the
rainbows we see.)
So here you are. You look up at one angle and see blue and another at
angle and you see red. Now, if you've got some algebra background you can
go to the next page