Wind creates the most common waves. These waves begin in the open ocean where the energy of the wind is transferred to the water.
Energy, not water, is the driving force behind waves. Picture a ball floating on the water at the beach. When a wave reaches it, the ball rides to the top of the wave and then down the wave’s back side, ending up almost exactly where it began.
Meanwhile, the wave continues on toward the shore. If water rather than energy were on the move, the ball would be carried ashore on the wave. Instead, we see energy passing through the water in the form of the wave.
Oceanologists—people who study oceans—have not yet completely figured out how this transfer of energy from the wind to the water takes place. They do know, however, that wind blowing over the ocean surface is deflected, or turned away, by the water.
Air deflected by an object rises, drawing the object upward. This upward movement is called lift. Not only water, but bird and airplane wings respond to lift. Under stormy conditions, the wind pushes down on the water like a hand. Both of these actions cause waves.
While the wind’s energy travels through the water, the water does not stay still. Particles in the water show how the water moves. Under a wave, energy sets the particles moving in circular patterns.
As the energy decreases in deeper water, particles move in smaller circles until it becomes a gentle rocking motion at great depths. The motion disappears around 325 feet (100 meters) down.
Wind blowing over water creates waves. Individual water particles do not move along with the wave. They move in a circle, as indicated in this drawing.
Waves break at the shore because the water particles at the bottom of the wave are slowed down by the rising ocean floor, while the water particles at the top of the wave continue to move.