Principle

Square and round metal plates are brought to vibrate through acoustic stimulations by a loudspeaker. When the driving frequency corresponds to a given Eigen-frequency (natural vibration mode) of the plate, the nodal lines are made visible with sand. The sand is expelled from the vibrating regions of the plate and gathers in the lines because these are the only places where the amplitude of vibrations is close to zero.

Benefits


Experiment set-up particularly suitable to visualize resonance

Many experiment variations possible

Use digital function generator for quick frequency-tuning in other experiments


Tasks


Determine the frequencies at which resonance occurs and drive the plate specifically at these frequencies.


What you can learn about


Wave length

Stationary waves

Acoustic vibrations

Two-dimensional standing waves

Eigen-modes