Did you know that humans can detect the polarization of light? There is a phenomenon called "Haidinger's brush". I just found out about this recently, and I was intrigued. Try it. An LCD screen is a good source of polarized light. Go to a white screen, such as a blank Firefox tab. Look at the screen, and tilt your head from side to side. You should see a yellowish hourglass shape in the center of your visual field. There is actually a blue hourglass that runs perpendicular to it, but it's very faint, at least for me. The yellow hourglass is very easy to see for me. It's a dirty yellow-brown color. I'm surprised I never noticed this before. If I'm not mistaken, the direction of polarization is along this blue portion, perpendicular to the yellow. If I had a polarizing filter I could test this. http://en.wikipedia.org/wiki/Haidinger's_brush
an old non functioning LCD type calculator or game has at least one polarizing filter in the display. most of these can be taken apart and the filter salvaged.
