Hello all, i'm new to the board here. I have been scratching my head over an example in one of the books I was reading so I looked it up on google. I found an explanation differing from what i'd read, so I thought I would pose the question to this community and see what you think. I have no real physics experience beyond highschool, but i've been reading books for interest sake. The book I was reading that prompted this question is "The God Effect" by Brian Clegg, First Edition. On page 60 there is a description and diagram of what happens when light passes through a series of polarized filters. If unpolarized light passes through a horizontal filter and then meets a vertical filter, no light passes through the vertical filter. However, if a 45 degree polarized filter is placed between the horizontal and vertical filters, there is some light that makes it through all three filters. The book states that light that passes through the first (horizontal) filter becomes horizontally polarized. Thus this light cannot pass through the vertical filter. However, the act of placing the 45 degree filter in line causes photons of the light to be changed so as to have a 50:50 chance of being vertically or horizontally polarized. Thus, 50% of the light to pass through the 45 degree filter will make it through the final vertical filter. I then found a website claiming that the filters actually change the direction of the wavelengths of light, reducing their magnitude more and more the further away from the degree of polarization the initial light is. Thus light gets squished into 0 degrees, then cannot pass through a 90 degree filter. But when you place the 45 degree filter in, the 0 degree light gets squished to 45 degrees, then that light gets squished further to 90 degrees. Link to second explanation website. It seemed to me that the first explanation had to do with the probability of a photon being polarized in any direction. That the first filter removes all the non-horizontally polarized photons, and that then the 45 degree filter somehow effects the photons so that they now have a probability of being either vertically or horizontally polarized; allowing the vertical ones to pass though the final filter. But I can't see how this works, honestly.. it doesn't sit well with me. The website explanation seems better. Am I just missing something fundamental? Are these two explanations really saying the same thing? What is the correct explanation? Sorry for being a physics nub :P at least i'm interested!