Question

If you look at the sky in a particular direction through a polaroid and rotate the polaroid around that direction, what will you see?

Answer 1

The intensity of light from the sky will vary as the polaroid is rotated because scattered sunlight is partially polarized. It will be brightest when the transmission axis is parallel to the preferred direction of polarization and dimmest when it is perpendicular. Complete extinction generally does not occur because the scattered light is usually only partially polarized.