Ernst Chladni

Ernst Florens Friedrich Chladni (, , ; 30 November 1756 – 3 April 1827) was a German physicist and musician. His most important work, for which he is sometimes labeled the father of acoustics, included research on vibrating plates and the calculation of the speed of sound for different gases.

Chladni's technique, first published in 1787 in his book Entdeckungen über die Theorie des Klanges ("Discoveries in the Theory of Sound"), consisted of drawing a bow over a piece of metal whose surface was lightly covered with sand. The plate was bowed until it reached resonance, when the vibration causes the sand to move and concentrate along the nodal lines where the surface is still, outlining the nodal lines. The patterns formed by these lines are what are now called Chladni figures. Similar nodal patterns can also be found by assembling microscale materials on Faraday waves.

Works

First page of a 1787 copy of "Entdeckungen über die Theorie des Klanges"Entdeckungen über die Theorie des Klanges, Leipzig 1787. Die Akustik, Leipzig 1802. French translation: Traité d'acoustique, Paris 1809. Also in Neue Beiträge zur Akustik, Leipzig 1817. Beiträge zur praktischen Akustik und zur Lehre vom Instrumentbau, Leipzig 1821 . , Leipzig/Riga 1794. Über Feuermeteore, Vienna 1820. Über die Hervorbringung der menschlichen Sprachlaute, Leipzig 1824. Kurze Übersicht der Schall und Klanglehre, nebst einem Anhange die Entwickelung und Anordnung der Tonverhältnisse betreffend, Mainz 1827.

Gallery

+ Chladni plates