A violin bow is dragged sideways across a thin metal plate, until a high pitched tone is audible. The plate is mounted on a tripod around its central point, and is able to rotate freely. Sand is scattered across the surface of the plate, and forms symmetrical lines of various forms, depending on the pitch of the sound produced.
How does it work?
The violin bow can stimulate the plate to vibrate in various patterns, which match a certain pitch. These specific frequencies match natural oscillations in the metal. This causes two adjacent surfaces to move up and down, with the sand caught in between, showing us indirectly which areas are vibrating.
