The Moon's Phases

Have you noticed that the Moon changes shape? Sometimes it looks round and sometimes it looks like a sliver. These shapes are called phases. The Moon goes through a full cycle every month. It does not actually change size.

Why the Moon Changes

The Moon does not make its own light. It reflects sunlight from the Sun. As the Moon orbits Earth, we see different parts lit up. When it is between Earth and the Sun, we see its dark side. When Earth is between them, we see the whole bright side.

The Main Phases

There are eight main Moon phases. They go from new moon to full moon and back. A new moon is invisible because the lit side faces away from us. A full moon is bright and round. Half-moons are called first quarter and last quarter.

Fun Facts

• The Moon takes about 29.5 days to go through all its phases.
• A crescent moon looks like a curved sliver.
• We always see the same side of the Moon from Earth.

Did You Know?

Some calendars, like the Chinese and Islamic ones, use the Moon's phases to count months.