Moon Phases

The Giant Mirror

When you look at the Moon at night, it looks very bright. But the Moon does not make its own light. The Moon is a dark, rocky ball. It acts like a giant mirror — it reflects the bright light of the Sun back down to Earth.

Moving in a Circle

The Moon travels around Earth in a large circle called an orbit. It takes about 29 days to finish one full circle. As the Moon travels, the Sun's light hits it from different angles.

Because the Moon is always moving, we see different amounts of its lit side from Earth. Sometimes we see a full circle of light. Sometimes we see only a thin curve. These changing shapes are called the Phases of the Moon.

The 8 Phases

The Moon has 8 main phases during its 29-day journey. It starts as a New Moon — completely dark. Then light slowly grows on the right side through the Crescent, Quarter, and Gibbous phases.

At day 14 it becomes a Full Moon — a complete bright circle. Then the light shrinks on the left side back through Gibbous, Quarter, and Crescent, until it returns to darkness.