One of the easiest activities to teach moon phases using vanilla wafers and frosting is to make mini moon models. Starting with one round vanilla wafer as the base, have each student spread a layer of frosting over the entire cookie to represent the sunlight reflecting on the lunar surface. Have him take a bite out of his second cookie to represent a specific lunar phase, for example, biting a small piece off of the right side of a cookie to make a waxing crescent with its tiny sliver of reflected light showing. Place the cookie on top of the frosting and repeat for each lunar phase.
Explore the light and dark of the lunar phases with a multi-colored frosting activity. Use chocolate and vanilla flavors to represent the shadow and light that make up each moon phase. Start with a flat, circular vanilla wafer as the moon itself. Create each phase, cookie by cookie, by spreading the different colors onto the wafer's surface. Start with a new moon, completely covering the cookie with chocolate frosting. Move on to a waxing crescent, using mostly chocolate frosting with just a sliver of vanilla on the right side. Continue on to the remaining phases using the corresponding amounts of each color of frosting for the shaded and light areas.
Have students create miniature versions of the moon's phases by frosting individual cookies with white frosting. Instead of the subtractive activity of biting off parts of the moon, this additive project encourages students to create their own lunar phases by spreading or painting the correct amount of icing onto each wafer. Have students use a plastic spoon, wooden craft stick, new paint brush or even a clean finger to create each moon phase. For example, finger paint half of the cookie with white frosting to make a first quarter moon.
Although making a moon tracing may not be an edible activity, using food as a science material can be more interesting to students than more typical items. Ask each student to fold a piece of construction paper into eight sections. Label each section as one of the lunar phases. Place eight cookies onto the paper, one in each section. Trace the entire cookie for the new and full moon. For the remaining phases take a bite or cut the cookie to match the corresponding shape and trace each of the bitten cookies. Remove the cookies and fill in the shadow areas with a dark crayon and paint white frosting on the light sides.