Ernst Chladni
Ernst Florens Friedrich Chladni (IPA ['ɛʀnst 'floːʀɛns 'fʀiːdʀɪç 'kladnɪ] November 30,
1756–April 3, 1827) was a
German physicist.
Chladni was born in Wittenberg. His important works include research on vibrating plates and the calculation of the speed of sound for
different gases.
Chladni Plates
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 über 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 adjustable 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.
See also
Further reading
- 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
External links
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