Cymatics

Cymatics is the study of visible sound and vibration, typically on the surface of a plate, diaphragm or membrane. Directly visualizing vibrations involves using sound to excite media often in the form of particles, pastes and liquids.
The generic term for this field of science is the study of 'modal phenomena,’ named 'Cymatics' by Hans Jenny, a Swiss medical doctor and a pioneer in this field. The word 'Cymatics' derives from the Greek 'kuma' meaning 'billow' or 'wave,' to describe the periodic effects that sound and vibration has on matter.
The apparatus employed can be simple, such as a Chladni Plate (a flat brass plate excited by a violin bow) or advanced such as the CymaScope, a laboratory instrument that makes visible the inherent geometries within sound and music.