Purpose:Show two-dimensional standing waves in a metal plate
Description:The Chladni plate is a system for creating and illustrating two-dimensional standing waves in a surface. A variety of flat plates can be mounted on the oscillator (including square, circular, and violin-shaped plates). As the plate vibrates, fine white sand is shaken about and traces out the nodal lines of the vibrations of the plate.
The system operates by means of magnetostriction. A thin-walled annealed nickel tube is used to drive various Chladni plates. The nickel tube is threaded into the center of the plate, and inserted through a coil under the plate, which rests on a thick felt surface. An oscillator in the 10-30 kHz frequency range drives a 20-Watt audio amplifier to provide the current creating the magnetic field. The field is biased by a small horseshoe magnet to avoid frequency doubling in the tube. A mirror allows larger groups to view the plate easily.