Editing Cymatics (section)

==History==
On July 8, 1680, [[Robert Hooke]] was able to see the nodal patterns associated with the modes of vibration of glass plates. Hooke ran a [[Bow (music)|bow]] along the edge of a glass plate covered with flour, and saw the nodal patterns emerge.<ref name="ODS">[https://web.archive.org/web/20130408234655/http://www.ilt.columbia.edu/projects/bluetelephone/html/chladni.html Ernst Florens Friedrich Chladni], ''Oxford Dictionary of Scientists,'' Oxford Univ. Press, 1999, p. 101 (archive.org link). Accessed 24 August 2015.</ref>

The German musician and physicist [[Ernst Chladni]] noticed in the eighteenth century that the modes of vibration of a membrane or a plate can be observed by sprinkling the vibrating surface with a fine dust (e.g., [[lycopodium powder]], flour or fine sand). The powder moves due to the vibration and accumulates progressively in points of the surface corresponding to the sound vibration. The points form a pattern of lines, known as "nodal lines of the vibration mode". The normal modes of vibration, and the pattern of nodal lines associated with each of these, are completely determined, for a surface with homogeneous mechanical characteristics, from the geometric shape of the surface and by the way in which the surface is constrained.<ref name="ODS"/>

Experiments of this kind, similar to those carried out earlier by [[Galileo Galilei]]<ref name="amsci">J. McLaughlin, "[http://www.americanscientist.org/my_amsci/restricted.aspx?act=pdf&id=3057428159866 Good Vibrations]" in ''American Scientist'', July–August 1998.</ref> around 1630 and by Robert Hooke in 1680, were later perfected by Chladni, who introduced them systematically in 1787 in his book ''Entdeckungen über die Theorie des Klanges'' (Discoveries on the theory of sound). This provided an important contribution to the understanding of acoustic phenomena and the functioning of musical instruments. The figures thus obtained (with the aid of a violin bow that rubbed perpendicularly along the edge of smooth plates covered with fine sand) are still designated by the name of "Chladni figures".

[[Michael Faraday]] discovered that liquids in a bowl produce regular patterns when the bowl is vibrated, so-called [[Faraday waves]].