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Pioneers of Sound


Ernst Florens Friedrich Chladni


30-11-1756 to 4-4-1827

Born in Wittenburg, Germany, Chladni's Father demanded that he study Law not science. He obtained his law degree in 1782 from Leipzig. After the death of his Farther he abandoned law for the study of physics and mathematics, especially the science of sound. Chladni achieved recognition for his pioneering work in the mathematical analysis of acoustics. This research was built on the early experiments of Robert Hooke at Oxford University.

On July 8th 1680 Hooke conducted the experiment of glass vibrating 6.4.8. places. This was done by sprinkling flour on a glass plate, and bowing on the edge of glass. Hooke observed that the motion of the glass was to vibrate perpendicular to the surface of the glass, thus producing circular patterns in the flour. This phenomenon was rediscovered by Chladni in the eighteenth century, and given his name "Chladni figures". Chladni modified the experiment by taking thin metal plates and covering them with sand and causing them to vibrate by the bow of a violin. The sand collected in nodal lines that produced symmetrical patterns similar to Hooke's flour on the glass plate. These findings influenced Faraday's thinking about lines of force in his electrical and magnetic experiments.

Chladni produced two musical instruments the Clavicylinder and the euphonium. The Clavicylinder was a redesign of Hooke's "musical cylinder" or string phone. In July 1664 Hooke conduced an experiment to show the number of vibrations of a taught string, made in a certain time, gave a certain tone or note. It was found that "a wire making two hundred seventy two vibrations in one second of time sounded G Sol Re Vt. in the Scale of all Musick". Hooke had noted that middle C had 272 beats a second.

Chladni was one of the first in the scientific community to state publicly that meteorites feel from the sky. He was ridiculed for this belief until Jean Baptist Biot confirmed it to be the correct in 1803.

Chladni wrote a number of treatises on the theory of sound and acoustics. He died in Breslau in 1827.

References:

The New Universal Encyclopedia, Vol 3.
National Encyclopedia, Collier, Vol 3.
Oxford Dictionary of Scientists- Oxford University Press- 1999
"An Early History of the Telephone 1664-1865"
The Internet



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