Underwater Dunes
Create submarine dunes
Spin the glass ball and watch the sand moving in water. The most frequent movements of seawater are tides, waves and ocean currents. The term tides denotes the regularly repeated rising/incoming (ebb tide) or receding/outgoing (flow tide) of sea level. It is caused by the gravitational force of the Moon and the Sun. Waves on the sea surface are produced mainly by wind, and less often by submarine slides, volcanic activity or an earthquake. Ocean currents transport huge quantities of water over great distances. Moving water shapes the sandy sea bottom just as the wind shifts sand in the desert.
