Here's a neat little demo that you can use to wow your non-photographic friends, or your favorite photo novice. Thirty-five seconds into the polarizing filter intro above, Christopher Frost captures a series of shots with and without a polarizer, and the difference is striking.

The video itself is several years old, offering a basic overview of circular polarizers, how they work, and why they're 'so neat.' It's useful for beginners, but the part we enjoyed most was the demo—where Frost laps a polarizer onto his camera, shoots video of some reflective surface, and turns it while the video runs.

The surface of a river, a storefront window, stacks of books, even some reflective leaves later on in the video, all of them take on a totally different character when you remove the reflections by using a polarizer:

Check out the video up top to see all of the examples (the video will automatically start at the 35 second mark). And on the off chance you don't know what a polarizer is or how it works, you'll get a basic photography lesson while you're at it.