What causes tides in the ocean?

Tides are caused by the gravitational pull of the Moon and the Sun on Earth’s oceans. The Moon’s gravity pulls the water toward it, creating a bulge, and a second bulge occurs on the opposite side of Earth due to centrifugal forces as the Earth and Moon orbit their common center of mass. The Sun also exerts a gravitational pull, but it is less powerful than the Moon’s. The alignment of the Earth, Moon, and Sun during new or full moons causes spring tides, with higher than normal high tides.