What does polarization have to do with sunglasses?
A lot. For example, fishermen often wear polarizing sunglasses to try to
reduce reflected glare off of the surface of the water. You've probably
noticed this before when you've been at the beach. Try an experiment and see
for yourself, but remember to check that you really have a pair of polarizing
sunglasses. Most sunglasses are not polarized.
Click and drag on the lens to turn it.
Click outside the lens to move it.
That seems weird. If the lens is vertical, all of the sunlight reflected off
of the water comes through. If the lens is horizontal, none of the reflected
light comes through. Why does it matter which way I hold the lens?