This video showing water misbehaving for the camera makes my brain hurt in a good way. One of the Youtube commenters writes underneath that it’s like they’ve found a glitch in the matrix. Maybe they have? No, not really of course, it’s just science, but it certainly looks strange and unexpected. It’s a dead simple set up really: some chap ran a rubber hose down next to a speaker so that when the speaker produces sound it vibrates the hose.
The camera is set to 24 fps. The tone generating software is set to 24hz. Turn on the tap. Let the magic begin. If you want the water to look like it’s moving backward set the frequency to 23hz. If you want it to look like it’s moving forward in slow motion set it to 25hz.
It’s quite, quite strange. I had to rub my eyes and blink a lot before I believed what I was seeing. Unfortunately you wouldn’t actually see this happening with your bare eyes, it’s the fact that the shutter and the sound wave are synced that gives you this rather pleasing optical illusion….