Phases of the Moon (Adapted from LHS GEMS teacher guide: :”Earth, Moon and Stars” Modified for visually impaired students) Preparation: Ask students • What does the Moon look like? (They heard about crescent Moon,

full moon, conclude it seems to change shape).

• What is the Moon made of? (Rock)

• How does a chunk of rock change shape? (It does not)

• How does a chunk of rock shine so brightly that we can see it? (The Sun shines on the Moon, making it look bright in the sky. Remind them how, when Sun shines on Earth, it is light (daytime) on half of Earth, and dark on the other half. So it is on the Moon, the Sun can only make one half shine, the other is dark.)

• We know the Earth orbits the Sun, what about the Moon? (It orbits the Earth and goes with the Earth around the Sun).

• What does it say about the positions of the bodies? (Changes as time goes by, so what we see of them also changes, thus we see lunar phases)

Three dimensional demonstration

Designate on wall of the classroom to be the (direction) to the Sun. Have each kid take a Styrofoam Moon ball in one extended hand.

• Question: What plays the role of the Earth? (Their head)

Now ask them to point the round side of the handle toward the “Sun”. Ask them to feel the ball with the other hand. (They should feel only one structure, and see only one color). Ask them what side of the Moon do they feel/see the dark or the lit side?

Instruct them to slowly turn counterclockwise some amount (toward their right shoulder) while keeping the flat side pointing to the “Sun”. (Some students might need help with the correct pointing). Now ask them to feel the surface of the ball with their other hand, and to describe what they feel. Repeat at different positions until they are back facing the Sun.

Students should notice that they feel different amounts of the different textures (or see different amount of different colors). Since the different textures correspond to dark or bright areas, the observable proportion of those areas changes as the Moon goes around.

Repeat the activity but now identify the phases with their names, new moon, First quarter, full moon etc.

• Question: Why is the first quarter a quarter when it is half bright, half dark? (It is one quarter of the way along its orbit)

To reinforce the concept go through the phases using the attached illustration enlarged and copied to swell paper. It shows that does not matter where the Moon is on its orbit, it is always the left side what’s illuminated. How much of it we see depends on where is it on the orbit, that is what is the angle between the Sun, the Earth and the Moon. The teacher can help the student by holding a piece of paper tangential to the orbit. Now the student can feel only the parts facing the earth, and realize the changing proportions. Extension: Discuss what it means for an object to rise or set (being visible in the East or West), and what is noon ( the Sun is directly South). How far apart those direction are in angles? Ask students about what time the full Moon rises. To figure out remind them the graph, look for the angle between the Moon-Earth-Sun (180°). Sun is 180° from East, so we are at Sunset. Repeat for other phases, and try with Moon setting instead of rising.

Instructions for making one tactile Moon ball 4 inch Styrofoam ball Small packet of 8 mm sequins Small-headed pins Wooden trim with one flat and one round side Draw the line dividing the ball in halves. Pin the sequins on the ball starting along this line. When done continue toward the pole slightly overlapping the sequins. You probably have to put extra pins around some edges. Make sure the pin goes in perpendicularly, and that it is pushed in completely. Use dark colors for white ball, light for dark. Decide ahead of time which one represents the bright side. Push in the handle so the round side marks the bright side. (Experience show it is easier to hold through the activity this way. Judit Gyorgyey Ries

Judit Györgyey Ries UT Austin/Astronomy Department McDonald Observatory moon@astro.as.utexas.edu