Ernst Florens Friedrich Chladni

Born Nov. 30, 1756, in Wittenberg; died Apr. 3, 1827, in Breslau, now Wrocław, Poland. German scientist in experimental acoustics and meteoritics.

In accordance with the wishes of his father, a prominent jurist, Chladni studied law in Wittenberg and in Leipzig. He was the first to undertake experimental studies of various acoustic phenomena, many of which were theoretically explained much later. He discovered longitudinal vibrations in strings and rods and studied the vibrational modes of rods, tuning forks, bells, and plates. He observed torsional vibrations in rods.

Chladni was the first to determine with reasonable accuracy the speed of sound in various gases. He also measured the ratios of the speeds of sound in various materials to the speed of sound in air. He explained echoes and established the upper threshold of audibility. In 1787 he described the figures that are formed in sand sprinkled on the surface of a vibrating elastic plate; such figures are called Chladni figures.

In 1794, Chladni explained correctly for the first time the origin of pallasites. He also developed the theory that meteorites originate in space and burn up when they enter the earth’s atmosphere.

Chladni invented peculiar musical instruments which he called the clavicylinder and the euphonium. He became a corresponding member of the St. Petersburg Academy of Sciences and Arts in 1794.