Target Age Group
Elementary

Ojbective
Students will understand why the Moon appears to be a different shape on different nights.

You will need
5 sandwich cookies, paper plate, orange, apple, an adult, milk optional

What to do
1. Wash your hands. Ask an adult for 5 sandwich cookies. Say “please” and make sure you have just eaten a healthy meal before you ask. If the answer is something like “That’s an awful lot of cookies,” explain that it is for an important science project and invite him or her to join in.

2. Study the “Phases of the Moon” drawing on this page. If you take the tops off the cookies, can you duplicate those shapes?

3. Now ask the adult for an orange and an apple. (This will probably be easier than asking for the cookies.) Make an arrangement on the table with the orange as the Sun and
the apple as the Earth. The orange and the apple represent the positions of the Sun and Earth, but not their relative sizes; they are not to scale. One at a time, position the Moon
cookies between the Earth and the Sun to show the phases.

4. Where does the Sun need to be for you to see a full Moon on Earth?

5. When you are done with your activity, enjoy cookies and milk while reading Moon Cake by Frank Asch or If You Decide to Go to the Moon by Faith McNulty.

What's Going On?
As the Moon orbits the Earth, sunlight is reflected off different parts of the Moon. The part of the Moon where the sunlight is reflected is the part we can see. So, for a full Moon, your cookie would need to be positioned so that the Sun (orange) can shine on it and it can be fully seen from the Earth (apple). The orange and the apple represent the positions of the Sun and Earth, but not their relative sizes; they are not to scale. For a more advanced Moon Phases activity, use a Styrofoam ball to represent the Moon, sticking a pencil in it to make it easy to hold. Form a circle of friends around a floor lamp with a bright bulb and no shade – the Sun. Move the Moon ball around you and observe how the light falls on the ball in different patterns depending on your – the Earth’s – position.

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