Tides are waves that form in the ocean because of the gravitational pull of the moon. The water moves with crests and troughs frequently, and the rise and fall of water are called the tides. The motion of the earth maintains water levels of the ocean at a continuous pace rising up and down.
This motion is due to the gravity of the planet and the centrifugal force. The gravitational pull of the moon is what causes the water to rise; however, the gravitational pull of the sun also creates tides. The surface water makes the currents in the water and the winds from currents in the oceans.
Water near the poles is cold, while near the equator it is warm. The temperature difference between the two waters is also responsible for the development of currents in the water.