Wb-5 Chladni Figures (Acoustically driven)

Aim

To demonstrate the modes of vibration of a plate.

Apparatus

  • Signal Generator
  • Public Address Amplifier
  • 50 Watt Horn Loudspeaker
  • Chladni Plates
  • Stand as Shown
  • Bell Jar
  • TV Camera and Monitor
  • Salt

Chladni Plate

Chladni Plate Setup.

Description

A plate supported at its centre is mounted a few millimetres above a horn loudspeaker driven by a signal generator and public address amplifier. Salt is spread across the surface and accumulates along nodal lines upon excitation. The apparatus is enclosed within a bell jar to reduce the sound level to acceptable levels. Modes of vibration are quite easily observed. Listed below are some frequencies that produce useful results. It will be observed that finer particles congregate at the antinodes. This is explained by the fact that these particles are predominately under the influence of the air motion caused by the vibrating plate.

Video

Chldani Plate Patterns

  • Triangle Plates

    Chladni Figure 1Chaldni Figure 2

    406Hz                                                                 1.342KHZ

  • Circular Plate

    Chladni Figure 5Chaldni Figure 6Chaldni Figure 7

    633Hz                                                    1.433KHz                                                1.724KHz

    Chladni Figure 8Chladni Figure 9Chladni Figure 10

    1.996KHz                                                 2.342KHz                                               3.042KHZ

  • Hexanganol Plate

    Chladni Figure 11Chladni Figure 12Chladni Figure 13

    402Hz                                         1.013KHz                                  1.314KHz

    Chladni Figure 14Chladni Figure 15Chladni Figurre 16

    1.364KHz                                   1.622KHz                                   1.959KHz

  • Square Plate

    Chaldni Figure 17Chaldni Figure 18Chladni Figure 19

    697Hz                                          1.295KHz                                   1.409KHz

    Chladni Figure 20Chladni Figure 21Chladni Figure 22

    1.538KHz                                    1.737KHz                                    1.824KHz

    Chladni Figure 23Chladni Figure 24Chladni Figure 25

    1.999KHz                                   2.366KHz                                    4.254KHz