Describe what causes the phases of the Moon to change each month.Hint: Think about how much of the sunlit side of the Moon we can see during the Moon's orbit.

The phases of the moon change each month due to the moon's orbit around the earth and the position of the moon, earth, and sun. Here are the steps that explain this process:

1. New Moon: The moon is positioned between the earth and the sun. The side of the moon that is lit by the sun is facing away from us, so we can't see it. The moon is in the sky during the day, but it's not visible. This is the start of the lunar cycle.

2. Waxing Crescent: As the moon moves in its orbit, a thin sliver of the moon becomes visible from earth. This is the sunlit side of the moon. Each day, more of the moon is lit by the sun, so the moon appears to grow or "wax."

3. First Quarter: The moon is now a quarter of the way through its orbit. Half of the moon is lit by the sun and visible from earth.

4. Waxing Gibbous: More than half of the moon is now visible. Each day, more of the moon is lit by the sun, so the moon continues to wax.

5. Full Moon: The moon is now on the opposite side of the earth from the sun. The entire side of the moon that faces the earth is lit by the sun, so we see a full moon.

6. Waning Gibbous: As the moon continues in its orbit, less of the moon is lit by the sun each day, so the moon appears to shrink or "wane."

7. Last Quarter: The moon is now three-quarters of the way through its orbit. Half of the moon is lit by the sun and visible from earth.

8. Waning Crescent: Only a thin sliver of the moon is now visible. Each day, less of the moon is lit by the sun, so the moon continues to wane.

9. New Moon: The moon is now back to its original position between the earth and the sun. The cycle starts again.

This entire process takes about 29.5 days, which is roughly one month.