This YouTube video demonstrates a physics trick right out of high-school science -- how to take a glass of water and a glass of whiskey and swap their contents, without using a third glass. It relies on the principle that whiskey is lighter than water and will float on top of it. The funny part is not the video, which is fairly straightforward, but rather the comments left by YouTube viewers, many of whom seem to think the video must have been faked. I guess they weren't paying attention in high-school science. I had a bottle of cheap whiskey on hand (Rebel Yell), so I tried the experiment myself, and I can attest that it definitely works. You just have to make sure not to allow the whiskey and water to mix too quickly, otherwise they'll combine together and you'll end up with two glasses of watered-down whiskey.