NMSAT :: Networked Music & SoundArt Timeline

1680 __ Cymatics — sound vibrations
Robert Hooke (1635-1703)
Comment : On July 8, 1680, Mr Robert Hooke (1635-1702) had been able to see the nodal patterns associated with the modes of vibration of glass plates. Hooke ran a bow along the edge of a glass plate covered with flour, and saw the nodal patterns emerge. Hooke had observed that the motion of the glass was vibrate 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". What Chladni did was to take thin metal plates and cover them with sand and caused them to vibrate. The sand collected in nodal lines producing symmetrical patterns similar to Hooke’s 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.Cymatics is the study of wave phenomena. It is typically associated with the physical patterns produced through the interaction of sound waves in a medium. A simple experiment demonstrating the visualisation of cymatics can be done by sprinkling sand on a metal plate and vibrating the plate, for example by drawing a violin bow along the edge, the sand will then form itself into standing wave patterns such as simple concentric circles. The higher the frequency, the more complex the shapes produced, with certain shapes having similarities to traditional mandala designs. The study of the patterns produced by vibrating bodies has a venerable history. One of the earliest to notice that an oscillating body displayed regular patterns was Galileo Galilei, who described it in his 1638 book, "Discorsi e Dimostrazioni Matematiche, intorno a due nuove scienze". (Hans Jenny)
French comment : L'art de la cymatique est un procédé qui rend les ondes sonores visibles. En 1632, Galilée est le premier à étudier le comportement des corps en vibrations, avant Robert Hooke en 1680, qui observe alors le comportement des nœuds associés aux vibrations. C’est en 1787, qu’Ernst Chladni donne réellement naissance à ce domaine en réalisant un travail considérable. De nos jours, les figures obtenues par la vibration de différents supports sont d’ailleurs appelées « images de Chladni ». Il établit une expérience simple afin de les retrouver : faire entrer en vibration une plaque métallique à l’aide d’une source sonore tout en disposant du sable sur celle-ci. Le principe est également très simple : le sable se déplace, grâce à la déformation du support provoquée par les ondes sonores, jusqu’à atteindre une « ligne nodale », c’est-à-dire une ligne dans laquelle il n’y a pas de vibration. En 1808, Chladni fait part de cette découverte à Napoléon, qui promet un kilo d’or à celui qui trouverait l’explication du phénomène. C’est Marie-Sophie Germain (1776–1831), mathématicienne française, qui remporta ce prix. Le nom « cymatique » est seulement apparu avec le scientifique Hans Jenny (1904-1972). Il est aujourd’hui considéré comme le « père » de ce domaine. En s’inspirant des expériences de Chladni, il fait de nouvelles expériences avec d’autres matériaux tels que les matériels piézo-électriques, les amplificateurs…. (Compiled from various sources)
Source : Jenny, Hans (1967). “Kymatic / Cymatics: The Study of Wave Phenomena”, Basilius Press, Basel.
Source : McVeigh, Daniel P. (2000), “An Early History of the Telephone 1664-1865”, electronic publication, with the help of Jean Gagnon, Daniel Langlois Foundation, and Don Foresta, MARCEL, 2000.
Urls : http://www.rexresearch.com/cymatics/cymatics.htm (last visited ) http://www.ilt.columbia.edu/projects/bluetelephone/html/chladni.html (last visited ) http://www.cymaticsource.com/ (last visited ) http://www.ted.com/talks/lang/fre_fr/evan_grant_cymatics.html (last visited ) http://www.youtube.com/watch?v=2wsVQntRLy8 (last visited )

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