how does sun glasses work?

Question

moongazer · Answer

Please answer clearly and explain the solution clearly and easy to understand. Thanks!
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anonymous · Answer

Depends.  Ordinary sun glasses simply absorb electromagnetic energy in the visible spectrum, and convert it to electromagnetic energy in the nonvisible infrared.  That is, they convert light to heat.  Your eyes can't see heat, so they relieve the stress on your eyes.  Of course, they get hot while doing so.  Their temperature rises until it is enough above ambient temperature (e.g. the temperature of the air around the sunglasses) so that the heat flow (which is driven by th temperature difference) is enough to get rid of the visible energy absorbed.

Polarized sunglasses work a similar way, but they preferentially absorb visible light with a horizontal polarization.  (That is, with the electric vector pointing horizontally.)  This is because when light is reflected from horizontal surfaces, e.g. the surface of flat roads, water, car hoods, et cetera, it tends to become partially horizontally polarized.  Polarized sunglasses thus preferentially block light reflected from flat surfaces -- which of course is the most annoying kind of light to be hitting your eye.