This activity follows the demonstration in the lunar phases science story. Children explore the dynamics of lunar phases to develop an understanding of the relative positions of our Moon, Earth, and Sun that cause the phases of the Moon as viewed from Earth. The idea that the Moon does not produce its own light, but simply reflects the light of the Sun, is reinforced.
Invite the children to revisit the science story accompanying “The Girl Who Married the Moon.” Share with the children that they will conduct the same experiment, but with a melon or grapefruit instead of an orange,so that the lunar phases will be easier to see.
Choose a child to hold the fruit representing the Moon. The child's head will represent our Earth. Choose another child to stand with a large flashlight in the corner of the room (or use a lamp); the lamp will represent the Sun. Before turning on the “Sun,” ask the children to observe the fruit.
Turn the light on and direct it toward the fruit. Invite the children to observe the bright side of the fruit that is reflecting the light, just like our Moon does.
Ask the children why we do not always see a full Moon, illuminated by the Sun, from Earth.
Have the child holding the fruit position it at arm's length, pointing at the light. Invite the other children to stand behind Earth.
Invite the children to move around the Moon to observe the side that is illuminated. Invite them to stand behind the Sun and discuss what they see.
Ask the child holding the “Moon” to slowly turn 180 degrees, or a half-circle in the direction that our Moon orbits Earth, keeping the Moon at arm's length and slightly higher than his or her head. Invite the other children to share their ideas of the Moon's direction of revolution ( counterclockwise if viewed from above in the northern hemisphere; or to the left ).
Make sure that all the children observe the change in illumination; they will have to move so they are observing the Moon from the same direction as the child holding the Moon.
Once the children are comfortable observing the changing illumination of the Moon, repeat the exercise so that each Moon phase is revealed. Start with the new Moon and have the child holding the fruit rotate in steps of 45 degrees, pausing at each of the eight phases to invite the children to make observations about the illumination and to identify the phase.
The children may wonder about Earth's rotation and the movement of the Moon. Remind them that Earth is spinning once on its axis each day, while our Moon is orbiting Earth approximately once each month. To illustrate this, pause the activity periodically and have another child hold the Moon wherever it is in its cycle. Have the child representing Earth spin slowly counterclockwise. Invite the other children to make observations about Earth's day and night cycle relative to the illumination of the Moon.
Invite the children to continue their exploration, having them exchange roles. Ask them to recount the patterns of changing illumination they observe. Use randomly selected cards of the Moon's shape to challenge them to explain the positions of the Sun, Earth, and Moon during that stage of illumination.
As an extension, share the Phases for Phrases song with the children and use the plates to identify and learn the names of the phases.
Connections to the National Science Standard(s)
Standard A (grades K–4): Model the phases of the Moon to understand lunar phases. Understand the pattern of movement of the Moon across the sky, as well as the observable cycle of changes in the Moon's shape within a month.Standard A (grades 5–8): Model the phases of the Moon to understand lunar phases. Understand the scientific explanation of how objects in the solar system have regular and predictable motion that explains such phenomena as phases of the Moon and eclipses.