Throughout the 1960s, up until his death in 1972, Swiss medical doctor and Anthroposophist, Hans Jenny took a methodological and exhaustive approach to documenting Cymatic phenomena. He coined the term “Cymatics” in his 1967 book, Kymatik (translated Cymatics).
The study is of visible sound and vibration, a subset of modal phenomena. Typically the surface of a plate, diaphragm, or membrane is vibrated, and regions of maximum and minimum displacement are made visible in a thin coating of particles, paste, or liquid. Different patterns emerge in the excitatory medium depending on the geometry of the plate and the driving frequency