Self-Induced Vibration of a Water Drop Placed on an Oscillating Plate

Vibration of a water drop placed on a vertically oscillating plate was observed, and the amplitudes and frequencies of the plate were measured with which the drop showed large amplitude vibrations. A special cloth was used so that the drop did not wet the plate. The results are compared with a simple theoretical prediction based on the Mathieu equation. The experimental data are shown to lie within the unstable growing region derived from the theory.