A colorful sunset fills the sky over the Pacific Ocean. This was taken at Crystal Cove State Park in California during low tide. Many of the tide pools were exposed and hermit crabs, anemones and other sea creatures could be seen. Both low and high tide usually occur twice a day approximately 6 hours apart. During a quarter moon, when the moon is at a right angle with the earth and the sun there is less variation between high and low tides. This is called a neap tide. But when there is a full moon or a new moon the tides are especially high and low. The gravitational force of the sun and the moon combine to generate more of a pull on earth's oceans. This is called a spring tide.