In 1787 Ernst Cladni, a German physicist and musician, published a technique that show different modes of vibration of a rigid surface. When running a violin bow over a sheet of metal or a membrane that is covered with sand or flour, the metal or membrane divides into regions that will vibrate in opposite directions.
Cladni’s technique was an expansion of the pioneering experiments of English natural philosopher, architect and polymath Robert Hooke. On 8 July 1680, Hooke observed wave patterns when running a bow over a plate of glass.
In the video above science enthusiast Steve Mould shows what the couscous does when a Cladni plate vibrates. The results are called Chladni figures. These are the patterns formed when the couscous settles in the areas with the least movement.
Video credit: Steve Mould