Got a Sound Wave Question for you thinkers

[DaMastaofFisix]

Hey everyone, I got a question for you. I was working after school one day with my Physics professor and we came across a question that said more or less; which of the following wave phenomena can be demonstrated only by light and not by sound? The choices were polarization, interference, refraction, diffraction, reflection and frequency. At first (and even to this point) my professor and I were 100 percent sure that everything could be demonstrated by a sound wave, but the answer was polarization. Apparently sound can't be polarized. But if that's the case, then how in the world does sound-proof glass work?....Interesting to say the least
Anyone brave enough to try and tackles this one? :rofl:

[Physics Monkey]

Basically, soundproof glass works by damping out the sound waves as they travel through it. See here for a more detailed description: http://www.madsci.org/posts/archives/dec96/850265675.Ot.r.html