Ernst Florens Friedrich Chladni
Born 1756 Died 1827
Born in Wittenburg in 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 vigorously pursued
his career in science. 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 formed the experiment of glass vibrating
6.4.8. places. This was done by putting flour on a glass plate,
and bowing on the edge of glass. Hooke had observed that the motion
of the glass was vibrate perpendicular to the surface of the glass,
and that the circular figure of the flour changed into an oval
one way, and the reciprocation of it changed it into an oval the
other way. This phenomenon was rediscovered by Chladni in the
eighteenth century, and given his name "Chladni figures". What
Chladni did was to take thin metal plates and cover them with
sand and caused them to vibrate. The sand collected in nodal lines
producing symmetrical patterns similar to Hookes flour on the
glass plate. It is also important to note that this influenced
Faraday in thinking about lines of force in magnetic in his electrical
experiments.
Chladni also produced two musical instruments the euphonium and
the Clavicylinder. The Clavicylinder was a redesign of Hookes
"musical cylinder" or string phone. In July 1664 Hooke produced
and experiment to show the number of vibrations of an extended
String, made in a determinate time, requested to give a certain
Tone or Note, by which 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 found that middle C
had 272 beats a second, and on 1st September 1672 Hooke noted
the he had invented an easy way for "a musical cylinder with pewter
tips pinched between cylindrick rings".
Chladni was one of the firsts in the scientific community to state
publicly that meteorites feel from the sky. He was ridiculed for
this until Jean Baptist Biot confirmed it to be the correct in
1803. Its importance is that it influenced Faraday in thinking
about lines of force in magnetic and electrical experiments.
Pg 101 Oxford Dictionary of Scientists- Oxford University Press-
1999