You're right, the Moon's shape seems to change throughout the month! This is because of the way the Sun lights up the Moon as it orbits the Earth. Here's a breakdown:

* The Moon doesn't produce its own light. It reflects light from the Sun.

* The Moon orbits the Earth. As it orbits, the angle at which the Sun's light hits the Moon changes from our perspective on Earth.

* We only see the illuminated portion. We see different shapes of the Moon depending on how much of the illuminated half is facing us.

Here's a simple explanation of the Moon's phases:

1. New Moon: The Moon is between the Sun and Earth, so we can't see any of its illuminated side.

2. Waxing Crescent: A sliver of the Moon's illuminated side starts to become visible, growing larger each night.

3. First Quarter: We see half of the Moon's illuminated side, looking like a quarter of a circle.

4. Waxing Gibbous: The illuminated part of the Moon continues to grow, becoming more than half.

5. Full Moon: The Moon is opposite the Sun, so we see the entire illuminated side, making it appear round.

6. Waning Gibbous: The illuminated part of the Moon starts to shrink, becoming less than half.

7. Last Quarter: We again see half of the Moon's illuminated side, but now it's the other half.

8. Waning Crescent: The illuminated part of the Moon continues to shrink, until it disappears entirely.

The cycle then starts over again with a new moon.

It's fascinating, right? We get a new view of the Moon every night!