The Changing Moon
1Look up at the night sky, and you may see the moon. The moon is a big ball of rock. It is much smaller than Earth. The moon travels around Earth in a path called an orbit.
2The moon does not make its own light. It shines because it reflects light from the sun. That means the sun's light bounces off the moon, a little like light bouncing off a mirror. The half of the moon that faces the sun is bright. The other half is dark.
3From Earth, the moon seems to change shape. One night it may look like a thin curve. A few nights later it may look like a half circle, and later still like a big, round ball. The moon is not really changing. We just see a different amount of its bright half as it moves around Earth.
4It takes about one month for the moon to go through all of its shapes. Then the shapes start all over again.