Back to Lesson 4: HYDROSPHERE

Why do the tides rise and fall?

Ocean tides rise (flood) and fall (ebb) about twice every 24 hours. Tides are causes by the gravitational pull of the Sun and Moon on the Earth. They pull the oceans towards them. The land is pull too but water moves more easily, making a giant wave. As the Earth spins, the wave travels around the Earth, causing tides.