Polarization A
When we first discussed waves, you learned that in transverse waves the vibration was perpendicular to the direction of propagation. Well, if you stop and think about it, you should realize that there are an infinite number of directions that are perpendicular to any given direction of propagation. As a quick example, consider a light ray that is traveling out of your computer screen towards you. It could be wiggling in any direction, so long as it's parallel to the plane of the screen. The particular direction in which it is actually vibrating is called the polarization.
to do as you read
Normal light is composed of many individual light rays, each of which can be polarized in a different, random direction. We call such light randomly polarized. It is possible to make special filters, called polarizers, which will let through only the component of vibration in a particular direction. You'll get a chance to play with polarizers in class.
Here's a video demonstration, and a challenge question for you to answer at the end. (Click to play.)
