Look at the map we have here. This line in the center of the earth is the equator. Winds that blow AWAY from the equator move from east to west. These winds push the water as they go and cause the currents. Scientists are still studying the effects of currents on the earth.
Wind also causes waves.
The wind pushes against the surface of the water causing waves. When the crest of a wave tumbles into foam, a breaker forms. Breakers carry sand away from the beach. After many years, the force of waves can change the shape of a shoreline. Put about an inch of water in the other end of the pan.