What You Need:
- Styrofoam balls (baseball size)
- Black spray paint
- Glow-in-the-dark spray paint
- Card stock paper
- Light source with bright light bulb
What Do You Do?
- Ahead of time, prepare the styrofoam balls by spray painting them so that one half is black, and the other half is glow-in-the-dark.
- Fold the card stock paper to create a stand for the pencil.
- Stick the pencil into the styrofoam “moon ball”, exactly on the line between the two colors.
- Stand the moon ball in the stand with the pencil so that is can rotate well without falling down.
- Use the bright light in the room to act as the sun, and see the different moon phases as you rotate the moon ball.
The moon circles the Earth every 29 days. The Earth’s gravity pulls on it so that the same side of the moon is always facing us. Nonetheless, we see a different view, or phase, of the moon each night of the month. Just like the Earth, half of the moon is always in sunlight, and half in shadow. When the moon is between us and the sun, the lighted part is pointed away from us, so we don’t see it — this is the new moon. As the moon orbits the Earth, each night we see a greater part of the lighted side, until the whole sunlit side faces us (full moon). As the orbit continues, we then see less of the lighted side until the whole cycle is completed and starts again.