What is this sorcery!?
Apparently. It's simple. The hose is attached to a speaker which, as we all know, works by vibrating at certain frequencies. It pumps the air at those frequencies and that's how our ears picks up the information that our brains interprets as sound. Imagine that instead of a continuous stream of water, it's actually made up of droplets, shot out of the hose 240 times per second. That means every time the hose makes a little circle, it shoots out 10 drops. They come out in order, one after another, each at a slightly different angle around the circle from the one before it. If you connect the droplets you'd get a spiral pattern. The water itself is moving straight away from the hose, but the spiral pattern is what we see as we mentally connect the dots.
Who would've thought that you can actually create this cool effect with just a water hose and a speaker! You just gotta love science!
Physics has been a continuous revelation of the vastness of our human limitations. But you've actually seen this trick before! On TV and in movies, sometimes it looks like car or bicycle wheels are spinning backwards. It's the same principle; the camera rate is mismatched a bit from the rate the wheel is spinning. In one frame you see a spoke that's vertical, but in the next frame it's come almost-but not quite-all the way around. It does that every time, and on the video it looks like the wheel is spinning backwards. It's not a trick, not really. It's physics.
Watch the video as it shows how sound affects the movement of water! It's mindblowing!
From YouTube User brusspup