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.

Further reading

  • Jackson, Myles W. (2006) Harmonious Triads: Physicists, Musicians, and Instrument Makers in Nineteenth-Century Germany (MIT Press).
  • Rossing T. D. (1982) Chladni's Law for Vibrating Plates, American Journal of Physics 50, 271–274
  • Short biography, bibliography, and links on digitized sources in the Virtual Laboratory of the Max Planck Institute for the History of Science
  • Die Akustik, 1802 by Ernst Chladni at Universities of Strasbourg
  • (Accessed 5/31/08)
  • (Accessed 5/18/14)
  • Examples with round, square, stadium plates and violin shapes
  • Chladni plates
  • Electromagnetically driven Chladni plate
  • Use of Chladni patterns in the construction of violins
  • Chladni patterns for guitar plates
  • An explanation on how to construct a Chladni plate for the classroom
  • Other pictures of Chladni can be viewed at this site and at the Science and Society Picture Library.
  • Ernst Chladni at Monoskop.org