Whats up with tides? How do they work?

Tides are caused by the gravitational pull of the Sun and Moon on the Earth's surface. While most people associate tides specifically with the ocean, the entire planet is subject to tidal forces, as is the atmosphere, and in fact all celestial bodies are influenced by tidal forces. The large volume of water on the Earth has made the actions of the tides particularly notable and interesting. Discussions of the movements of the tides can be found in the most ancient writings of the world, suggesting that people have always been intrigued by the once seemingly mysterious rise and fall of water along the shoreline.

As the Earth rotates, it is tugged at by the Moon and Sun. Because the Moon is much closer, the pull of the Moon is approximately twice as strong as the pull of the Sun, which explains why the tides are so closely linked with the lunar day. As the Moon moves around the Earth, it creates a bulge of water on the Earth's surface which follows its movements, creating a tide. A corresponding bulge appears on the opposite side of the Earth, thanks to the centrifugal forces generated by the Earth's rotation.