Here's how it works:

* The moon doesn't produce its own light. It reflects sunlight.

* The moon orbits the Earth. As it orbits, the angle at which sunlight hits the moon changes.

* We see different phases of the moon because of this changing angle. When half of the moon is illuminated by the sun, we see a half-moon (also called a quarter moon).

* The illuminated half always faces the sun. This means that the side of the moon that's facing us during a half-moon is the half that's receiving sunlight.

Think of it like a giant ball. If you hold a flashlight to the side of the ball, only one half of the ball will be lit up. The same principle applies to the moon!