The gravitational pull of the Sun and Moon cause the Earth to experience a phenomenon known as tides. Tides change about every 6 hours and there are 4 a day. The tides change from high to low high to low. At high tide the water swells and comes up the shore to a higher point. During low tide, water recedes back towards the ocean. When the Moon is in its first and last quarters, the moon is located above the earth at a right angle. At this time the Suns gravitational force partially offsets the Moons gravitational force causing lower than normal tides called neap tides. When the Moon, Earth, and Sun are aligned, the Sun and Moon are pulling at the earth’s water with greater force causing an unusually high tide. These tides are called spring tides.