Ernst Chladni
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Ernst Chladni |
Ernest Florenz Friedrich Chladni (
November 30,
1756â€"
April 3,
1827) was a
German physicist.
Chladni was born in
Wittenberg. Because of his work on
vibrating plates and the calculation of the
speed of sound for different gases, some people have dubbed him the "founder of
acoustics".
Chladni Plates
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Chladni modes of a guitar plate |
One of Chladni's most well known achievements was inventing a technique to show the various
modes of vibration in a mechanical surface.
Chladni's technique, first published in 1787 his book,
Entdeckungen ueber die Theorie des Klanges, consists of drawing a
bow over a piece of metal whose surface is lightly covered with sand. The plate is bowed until it reaches resonance and the sand forms a pattern showing the nodal regions . Since the 20th century it has become more common to place a loudspeaker driven by an electronic
signal generator over or under the plate to achieve a more accurate adjustible frequency.
Variations of this technique are commonly used in the design and construction of acoustic instruments such as
violins,
guitars, and
cellos.
Other Works
He invented a musical instrument called Chladni's euphonium, consisting of glass rods of different pitches, which should not be confused with a brass
euphonium. He also discovered
Chladni's law.
In 1794, Chladni published, in
German,
Über den Ursprung der von Pallas gefundenen und anderer ihr ähnlicher Eisenmassen und über einige damit in Verbindung stehende Naturerscheinungen, (
On the Origin of the Pallas Iron and Others Similar to it, and on Some Associated Natural Phenomena), in which he proposed that
meteorites have their origins in outer space. This was a very controversial statement at the time, and with this book Chladni also became one of the founders of modern meteorite research.
* Rossing T.D. (1982)
Chladni's Law for Vibrating Plates, American Journal of Physics 50, 271-274
* Marvin U.B. (1996)
Ernst Florenz Friedrich Chladni (1756-1827) and the origins of modern meteorite research, Meteoritics & Planetary Science 31, 545-588
*
Examples with round, square, stadium plates and violin shapes*
Chladni plates*
Chladni Plate Mathematics by Paul Bourke
*
3-dimensional Chladni surfaces by Paul Bourke
*
Electromagnetically driven Chladni plate*
Use of Chladni patterns in the construction of violins*
Chladni patterns for guitar plates*
Modal Analysis of Percussion Instruments Using Vibrational Holography --
Vibrational holograpy uses coherent light instead of sand
*
Patterns on YouTube An example of Chladni patterns in rice
