Build a lesson on how the Earth rotates around the sun and introduce the concept of night as well as the reason why the moon is so bright in the sky. Explain to them that the moon is bright because the sun is shining on it at that time. Use a triangular approach and a mirror as well as a flashlight as the sun in your demonstration. Show them that the sun is shining from an angle onto the moon while it is daytime on the other side of the Earth. This demonstration will work best with very young students.
Demonstrate how the phases of the moon work using your classroom projector. Start off on the left side facing the students, the projector casting your shadow, so that they can understand that this is the first quarter moon. Move so that you are facing the students directly, which is the full moon. Continue to move in an orbit-like fashion explaining each phase of the moon. Remember to explain to younger students that although a portion of the moon may be dark, it is still present in the shadows.
Many students cannot understand the size of the moon and a demonstration on its relative size can educate them greatly. Use your class globe as the Earth, which is roughly the size of a beach ball. Explain to them that the moon would be the size of a softball in comparison. They may question that but in order to understand why it looks so small, explain or show them that it would be 40 feet away from the globe. Also note that a space shuttle would orbit less than a half-inch above the globe, which demonstrates just how big of a gap there is between the Earth and the moon. This lesson would be good combined with a lesson on depth perception.
Ask your students if they are aware of the differences between lunar and solar eclipses. They may have some idea, but you can demonstrate the difference using Earth, moon and Sun models. Have one student be the sun, another the moon and a third the Earth. Have the moon orbit around the earth and explain what happens when they reach the points where eclipses would occur. Show them pictures of both types of eclipses and caution them not to look directly at the sun, but that lunar eclipses are visible in a safe manner.