Cymatics (from the Greek kyma, meaning "wave" and ta kymatica, meaning "matters pertaining to waves"), is the study of wave phenomena, pioneered by Swiss medical doctor and natural scientist Hans Jenny (1904-1972). Over the course of more than ten years, Jenny conducted landmark experiments pumping acoustic energy into, and animating, otherwise inert powders and liquids into life-like, flowing forms that mimic patterns found throughout nature, art and architecture. All of these patterns are a direct physical manifestation of pure tone vibration: dynamic form induced by material vibration.
His work is documented in a remarkable book, Cymatics: A Study of Wave Phenomena & Vibration. A few videos are available as well: (1) Cymatics: The Healing Nature Of Sound, and (2) Cymatic Soundscapes.
Jenny's work builds upon much earlier work by Ernst Chladni who, in 1787, published "Discoveries Concerning the Theory of Music." This work introduced the basic physics of acoustics (the science of "sound"). One of Chladni's many practical (and aesthetic) discoveries was a way to make sound waves visible . By using a violin bow, stretched perpendicularly across the edge of flat plates covered with sand, he produced the patterns and shapes that today go by the term Chladni figures.
Jenny's work also overlaps a bit with the work of mathematician Nathaniel Bowditch, who was among the first to study the patterns generated by parametric sinusoidal waves called Bowditch curves, but are more often called Lissajous figures.
Apart from the incredible innate beauty of Jenny's patterns, there lies perhaps an even deeper, and deeply mysterious, "beauty" that has to do with the underlying patterns of nature. As Cathie E. Guzetta puts it so eloquently in "Music Therapy: Nursing the Music of the Soul"..."The forms of snowflakes and faces of flowers may take on their shape because they are responding to some sound in nature. Likewise, it is possible that crystals, plants, and human beings may be, in some way, music that has taken on visible form." You can read more in the article Cymatics: The Science of the Future.
More recently, work on oscillons has revealed many of the same mysterious features, including that of effective atomic and crytaline structures. The physics of "small" granular media (sand, powder, BBs from a toy shotgun,...) that sit between the microscopic (atomic) and macroscopic (and cosmic) is in its infancy. Two more articles on oscillons: (1) From waves to particles: the oscillon, and (2) "Localized and Cellular Patterns in a Vibrated Granular Layer" (Tsimring & Aranson, Phys. Review Letters, Vol. 79, No. 2, July 1997).