@587bmay27: I explained this to a different student, but am happy to repeat. I have four fun facts!
1. The moon gets its light from the sun.
2. The moon orbits around the earth in about 28 days.
3. The earth rotates on its own axis in 24 hrs, and
4. The earth moves around the sun in about 365 days.
Since we are not moving at the same speed with the universe around us, these movements change the appearance of the size ad shape of the moon. In reality, the size and shape of the moon doesn’t change at all.