Tide is the vertical level of water in a particular location, and is caused by the interaction of gravitational and centrifugal forces between the earth, the sun and the moon. These forces cause the water on the earth’s surface to flow toward areas that are closest to, and those farthest from, the sun. These areas experience what are called “high” tides. The areas on the earth’s surface where this water flows from experience what are called “low” tides. At any given time, two areas of the earth are experiencing high tides and two are experiencing low tides, depending on their ever-changing proximity to the sun and the moon as the earth rotates on its axis.