Demonstrating the Phases of the Moon

Demonstrating the Phases of the Moon Goals: Learn about the phases of the moon by using a model to “act out” the movement of the moon around the Earth, as the Earth circles the sun and how our view of the lighted areas of the moon (the phases as such) changes. Materials: • styrofoam spheres (3 inches or larger) – one per student • pencil – one per student • light with a 100 watt bulb (or more) with no shade, so it can shine in all directions. It should be at head level with students, so may have to sit up on a table. Procedures: 1. Clear floor space and put the lamp in the middle of the room. It represents the sun. 2. Each student will need to carefully spear the styrofoam ball with their pencil in the center until it is secure on the pencil. This “styrofoam lollipop” represents the moon. Each student represents the Earth. 3. Turn out the lights and cover the windows. This activity works best in full darkness. 4. Each student should hold the moon (by the pencil) in one hand. Students should spread out in a circle around the light giving themselves enough room to rotate 360° without bumping into other students. They will be rotating (as Earth does) and the moon with them. As the moon changes position in relation to the sun (the lamp), they will see different amounts of the styrofoam ball (moon) just like the phases of the moon. Here goes. New Moon 5. Start facing the light with your “moon” held out in front of you (between you and the light). How much of the moon is visible in this position? This is the “new moon” position and the side facing the Earth (you) should be dark. 6. Next, keeping your arm extended, rotate to the left (counterclockwise) 45° watching your moon. Notice that you can now see some of the white showing on your moon. You are in the waxing crescent moon phase. Waxing Crescent 7. Rotate again to the 90° position from the light (your side will be facing the light). Notice there is now more of your moon in light (about half). This is the first quarter moon phase. First Quarter Waxing Gibbous 8. Another rotation to brings you to a 3/4 moon or waxing gibbous moon. Full Moon 9. With your back to the light you should see all of your moon now. This is a full moon. 10. If you keep rotating in the same direction with will next see the waning gibbous phase. 11. Then the last quarter phase. Waning Gibbous 12. Then the waning crescent phase. 13. With your next turn you should be facing the light again with a new moon. Last Quarter Now you have demonstrated a full month of moon phases. Can you see how the moon always gets the same amount of sun? Can you see how we see it from different throughout each month? Now look at the diagram below. This is a view of the moon phases from above. This should help you further see how the moon is always lit on one side. This never changes. But the position of the moon as it circles the Earth changes, so we see the lit side from different angles throughout the month. Waning Crescent 1. 2. 3. 4. Waning Gibbous Full Moon Waxing Gibbous First Quarter Last Quarter Waning Crescent New Moon Waxing Crescent SUN Study the diagram below to understand why we see the different phases of the moon throughout each month. Note that: The moon always gets the same amount of sunlight - on just one side. When the moon is between the Earth and sun, we face the dark side, so cannot see the moon - This is the New Moon. When the Earth is between the moon and the sun, we only see the light side - Full Moon. In all the other phases we are seeing the moon’s lit side at an angle, as shown, so only see a portion of the lit side. Note that the waning side looks upsidedown. That is because you would be seeing the moon from the Earth’s surface (not from out in space the way the diagram is shown). Phases of the Moon - A Visual Model