When you go to the beach, you see tides in the water. Tides are caused by the gravitational pull of the moon at different parts of Earth. At one time, when there is one high tide, then on the opposite side of the Earth there is a low tide and vice versa. The high tide is where that part of the Earth is facing the moon. There are two types of tides: Spring tides and Neap Tides. Spring tides are formed from the combined force that produce a tide with great difference between consecutive low and high tided. They are produced when there is a full moon. A neap tide is when there is little difference between consecutive low and high tides and occur twice a month when the Earth is at a 90 degree position from the moon and the sun.