"See, how they work," the first said, "is the right lens is polarized vertically and--"

"Wait, what do you mean by 'polarized'?" said the second.

"A vertically polarized lets no horizontally polarized light in, and a horizontally polarized lens lets no vertically polarized light in," said the third. "If two perpendicularly polarized lenses are put together, no light is let through."

"So as I was saying, the right lens is polarized vertically, and the left horizontally, or vice versa, such that each eye sees a different picture."

The second had an idea. "So that means if I..." He closed his right eye, and smiled. "Yes, I can only see your right eye."

The fourth and final person (you, of course), sensed something wrong. First, you verified the second's observation. Then, you said...

Another factor is that reflected light is mostly (nearly all) polarized in the direction of the surface it is reflected off of.  That is why fisherman benefit from polarized sunglasses - the light is mostly horizontallly polarized off the horizontal water surface.

To "see" another person's face (eye), light must be reflected off it.  The face is approximately (much more so than horizontal) a vertical surface, therfore the light must reflect off with mostly vertical polarization.  To get there in the first place, the randomaly polarized outside light must go through the lens, become polarized in some direction by the lens, reflect off with vertical polarization, and go back through the lens.  Therefore the right lenses must have vertical polarization, or no one, even without the glasses, will see the eye very well, since the reflected light would not get past otherwise.

Since the mostly vertically polarized relfected light then goes throught a vertcally porlaized lens, it is "purely' vertically polarized.  This should be impossible to see through a horizontally polarized lens (filter), which is what a left eye would have (assuming all the glasses are the same), therefore the glasses are not all alike, and that what is "something wrong"

Edited on September 13, 2006, 9:43 pm

Edited on September 13, 2006, 9:44 pm

Posted by Kenny M on 2006-09-13 21:36:15