Interesting Physics - Photographs

Chladni patterns

Chladni patterns occur on a vibrating plate sprinkled e.g. with semolina. The powder gathers at the points of the plate that do not move (nodal curves) and in this way visualize the plate oscillations. Some of the patterns are very beautiful. Up to now there is no known general analytic solution for the modes of a square plate, so one can rely only on numerical computations. The plate can be brought to vibration by a violin bow but we used a speaker or a coil and a magnet. The coil or the speaker is connected to an amplifier and a computer sound card that is used as a tunable source of sine oscillations. In this Interesting Physics lecture we also made a huge speaker out of a coil, magnet and a basin as one can see in the last picture.