Cymatic History

A bit of a historical background check into cymatics for a better understanding, its a bit lengthy but 

On July 8th 1680 Hooke formed the experiment of glass vibrating. This was done by putting flour on a glass plate, and bowing on the edge of glass. Hooke observed that the motion of the glass vibrated perpendicular to the surface of the glass, and that the circular figure of the flour changed into an oval one way, and the reciprocation of it changed it into an oval the other way. 

This phenomenon was rediscovered by Chladni in the eighteenth century, and given his name "Chladni figures". Chladni took thin metal plates and covered them with sand and vibrated them. The sand collected in nodal lines producing symmetrical patterns similar to Hookes flour on the glass plate. It is also important to note that this influenced Faraday in thinking about lines of force in magnetic in his electrical experiments. - Source