Here's how it works:

* The sun is the source of light: The sun emits its own light, which is what we see as sunlight.

* The moon is a reflector: The moon itself doesn't produce any light. It's a large, rocky body that reflects the sunlight that falls on it.

* The Earth's rotation: As the Earth rotates, we face different directions in space. During the night, the side of the Earth facing away from the sun is in darkness. But because the moon is reflecting sunlight, we can see it even though the sun isn't directly illuminating the Earth.

Why we see different phases of the moon:

The different phases of the moon (new moon, crescent, full moon, etc.) are due to the changing angle at which we see the sunlit portion of the moon as it orbits the Earth.