The moon's gravitational pull causes ocean tides. Gravity is one main force that causes ocean tides.
Ocean tides results from the gravitational attraction of the moon and the sun on the oceans on the earth's surface.
Gravitational attraction of the sun and the moon causes the water in the oceans to bulge, and thus resulting to a continuous change between high and low tide. Spring tides for instance are created at new moon and full moon when the gravitational force of moon and that of the sun act together.
