Video: You know you're old as hell when the only way to find out what young people are doing is to have other old people explain to you what the youths of today are doing, because you don't actually know anyone young any more. That's basically water bottle flipping. If you've done it, you're young (or pretending to be young). If you've never done it, you're old. If you've done it with mercury instead of water, well, you're... a nerd. A cool nerd, but still.
Mercury is nearly 14 times as dense as water so you only need a little bit of it to match the water in weight. It gets interesting when the Backyard Scientist matches the mercury with the water in volume, because he basically starts flipping heavy bottles of fluid over and over again. Watch it below: