Chladni Plates
Chladni Plates were developed by Ernst F. F. Chladni (1756-1827) as part of his study of the vibration of plates clamped at one or more points. Fine sand, sprinkled uniformly over the plate, moved toward the nodal regions when a violin bow was drawn over the edge of the plate. This work drew the attention of other physicists, and the figures were discussed and analyzed by well-known scientific figures such as Weber, Kirchhoff, Young, Wheatstone, Savart, Biot, Poisson and Faraday.
The set of plates below is in the Garland Collection of Classic Physics Apparatus at Vanderbilt University, and was bought from Koenig about 1875. The 1889 catalogue of James. W. Queen & Co. of Philadelphia lists this apparatus as "Bench, with Screw Supports for Six Plates of Brass, three round and three square. Two plates of each shape are of the same size, but one double the thickness of the other. Each pair is accompanied by a third plate of the same thickness as the first, but of half the diameter... $25.00"