Want to see water flow zig-zag without benefit of creek banks to channel it? Check out this story here about what taping a water hose to a speaker can make the water flowing through the hose do.
The reason for the strange flow is that the sound vibrates a specific rate, which makes the hose vibrate as well. When the camera speed is synced to the frequency of the sound being broadcast through the speaker, then it can "see" the flow as a zig-zag stream in mid-air. Other frequencies, synced with the camera, make it look as though the water flows up towards the hose even though we know it is flowing down.
I have no doubt my high school science teacher would have loved to have tried an experiment like this, but I imagine she wouldn't have been allowed to have the speaker inside the room turned up loud enough to make it work. Wouldn't want to disturb the place with any learnin' or nothin', you know.