I had another thought about polarization on reflection at a dielectric
interface. Consider an air-glass (or vacuum-glass) interface with a
beam of light polarized in the plane of incidence, incident at Brewster's
angle. The incident beam causes oscillation of electric dipoles in the
glass. Both refracted and reflected waves are radiated by these dipoles.
The reflected waves would come off at an angle that would require them
to leave the *ends* of the dipoles; in fact that is a nice way to derive
Brewster's angle. Since the amplitude of radiation from the ends of a
dipole is zero, we can understand why no radiation is reflected in this
circumstance. That's a bit of a handwave, but I would use it (suitably
fleshed out) to explain it to high school students, and I would further
demonstrate it with the directionality of an AM portable radio which
shows related nulls in its reception pattern. (Yes, I know it is a
ferrite antenna, etc.)
Whewn I teach interference I often call attention to the fact that the
reception of FM in a car is often affected by interference. The minima
can be found by moving the car slowly (as at a traffic light) where the
signal strength is low enough that the AGC in the radio can't catch up.
Once one recognizes this pattern it is really quit neat!
A similar "aha orgasm" attends the realization that sometimes one can
see the stress pattern in an automobile rear window by chance without
wearing polarized glasses. I'll let you in on the circumstances that
make that possible later.