re: #125 ggt

For any angle, some of the incident light of one polarization is refracted into the water. There is a special angle (Brewster’s angle, which has some dependence on material properties) for which “some” means 100% —all the light of that polarization gets refracted into the water, with 0% reflected. Therefore, at that special angle, any relected light is completely polarized the other way. (horizontal, I think).

Hope that helps.