Abstract
A silicon oil droplet with a diameter of about 2mm dropped on a silicon oil pool was sustained for a long time period. The petri dish containing the liquid was vertically oscillated at 50Hz. The droplet kept its horizontal position on the surface of the liquid. When another vertical vibration of 500Hz is superimposed on the previous one, the droplet moved to another position and stayed there. Then, if the superimposed vibration was stopped, the droplet moved back to the original position. The droplet repeatedly moved between the two positions according to the state whether the 500Hz vibration was on or off. The two positions sensitively depended on the setup of the petri dish and the vibrator. The surface wave profile of the surface of the liquid pool was measured by a laser displacement meter. The time averaged surface profile slightly deformed from a flat plane. Several depressions were observed on the surface. However, the relations between the droplet's position and the depression's position were not obvious.
