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Cymatics, from (ギリシア語:κῦμα), meaning "wave", is a subset of modal vibrational phenomena. The term was coined by Hans Jenny (1904-1972), a Swiss follower of the philosophical school known as anthroposophy. 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. The apparatus employed can be simple, such as the old Chinese singing bowl, in which copper handles are rubbed and cause the copper bottom elements to vibrate. Other examples include the Chladni Plate〔(【引用サイトリンク】url= http://www.physics.ucla.edu/demoweb/demomanual/acoustics/effects_of_sound/chladni_plate.html )〕 and the so-called cymascope. ==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 along the edge of a glass plate covered with flour, and saw the nodal patterns emerge.〔(Ernst Florens Friedrich Chladni ), ''Oxford Dictionary of Scientists,'' Oxford Univ. Press, 1999, p. 101 (archive.org link). Accessed 24 August 2015.〕 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.〔 Experiments of this kind, similar to those carried out earlier by Galileo Galilei〔J. McLaughlin, "(Good Vibrations )" in ''American Scientist'', July–August 1998.〕 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". 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「cymatics」の詳細全文を読む スポンサード リンク
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