The moon's phase is a thin crescent or new moon when it is closer to the sun. The curved side of the moon points toward the sun. The phases of the moon are caused by the moon's position relative to the sun. Also, as the moon moves farther from the sun in the sky from night to night, the lighted portion increases from crescent to full phase. To demonstrate how the daily motions of the sun, the earth, and the moon affect the appearance of the moon.
Students use a model to explain the moon's monthly cycle of phases.
Students will demonstrate the revolution of the moon around the earth and how the reflection of the sun changes the shapes or phases of the moon. Schedule this activity to begin two or three days after the full moon during the morning hours. Ask for volunteers to draw the shape of the moon on the chalkboard. 1 two-inch polystyrene ball or any ball painted with white latex or other water based paint. Prepare headbands with a cut out model of the earth and explain to the students that their head is going to represent the earth.