Wind and waves
In addition to causing currents, the wind creates waves as it blows across the surface of the ocean. The stronger the wind is, the bigger the waves are. You may remember the beach on a windy day or a calm day. On windy days, big waves crash onto the shore. On a calm, windless day, the surface of the water is flat.
Scientists measure waves from their highest point, the crest, to their lowest point, the trough. Most waves are neither very big nor dangerous. However, some waves, such as those in a violent storm, are large enough to damage ships and hurt people on the shore. Careful swimmers and surfers do not go into the ocean when the waves are too big, and ship captains often change direction to stay away from a storm. The power of the wind and the waves can be deadly.