Hans Jenny (cymatics)
- For the soil scientist, see Hans Jenny (pedologist).
Life and career 
In 1967, Jenny published the first volume of Cymatics: The Study of Wave Phenomena. The second volume came out in 1972, the year he died. This book was a written and photographic documentation of the effects of sound vibrations on fluids, powders, and liquid paste. He concluded, "This is not an unregulated chaos; it is a dynamic but ordered pattern."
Jenny made use of crystal oscillators and an invention of his own by the name of the tonoscope to set plates and membranes vibrating. With the tonoscope, quartz sand is spread onto a black drum membrane which is 60 cm in diameter. The membrane is set into vibrations by singing rather loudly through a cardboard pipe. The sand now produces complex symmetrical forms, known as Chladni patterns named after Ernst Chladni who discovered this phenomenon in 1787. Low tones result in rather simple and clear pictures, while higher tones form more complex structures.
Jenny's work influenced Alvin Lucier and, along with cymatics work by Ernst Chladni, helped lead to his composition Queen of the South. Jenny's work was also followed up by Center for Advanced Visual Study (CAVS) founder György Kepes at MIT.  His work in this area included an acoustically vibrated piece of sheet metal in which small holes had been drilled in a grid. Small flames of gas burned through these holes and thermodynamic patterns were made visible by this setup. Also, the DVD special edition of The Hafler Trio's work Exactly As I Say includes a DVD containing material "based on and extended from techniques suggested by Prof. Hans Jenny".
Based on Jenny's work, photographer Alexander Lauterwasser captures imagery of water surfaces set into motion by sound sources ranging from pure sine waves to music by Ludwig van Beethoven, Karlheinz Stockhausen, and even overtone singing.
- 1954: Der Typus (The Type) a study in morphology
- 1962: Das Gesetz der Wiederholung (The laws of Repetition)
- 1967: Kymatic (Cymatics) Volume 1
- 1972: Kymatic (Cymatics) Volume 2
- Deschin, Jacob (April 28, 1968). Science Vibrates To Make Pictures. New York Times