One of the YT comments: "In reality the sound (inaudible) being produced by the speaker causes the water stream to be periodically stopped. To the naked eye it would looks like a continuous stream of water drops. If you shoot the stream of water drops with a camera that has it's frame rate synced with the water drops the drops will appear to stay still as each frame shows the water in the exact same formation it was in in the previous frame.
Its same effect that makes helicopter blades and car wheels look weird on film"
