On a clear night, the moon shines brightly overhead. You might think that the moon gives off light, but it does not. Light from the sun reflects off the moon‘s surface. Sometimes the moon looks like a large ball in the sky. Other times it looks like a tiny sliver.

　Myths, or legends, were made up by early people to explain why the moon changes shape. The early people of Greenland which is an island in North America thought the sun goddess was chasing her brother, the moon god, across the sky. The moon god ran so much that he forgot to eat, so as days passed, he became thinner. Finally, the moon god had to stop and eat. He got bigger, and the chase began all over again. 

　Today people understand why the shape of the moon changes. The changes in the shape of the moon are caused by the way the moon moves in space. The moon moves in two ways. It rotates, or spins around like a top. It takes the moon about twenty-nine days to rotate once. It also travels in a path around the earth called an orbit. The different shapes of the moon are called phases. This is what the phases of the moon look like:full, waxing gibbous, half moon, waning, waxing. The phases of the moon in order are: full, waning gibbous, half moon, crescent, new moon, waxing crescent, half moon, waxing gibbous, and full.