Content Understanding Page

            Observing the moon and documented my observations in drawings, pictures, and commentary has helped me to gain a better understanding of the monthly lunar phase. Now, I find myself looking for the moon each time I go outside after dark. I also look at and analyze the moon to see where it is in the lunar cycle. In order to explain the phases of the moon it is important to note that at any given time only half of the moon is illuminated by the sun while the other half remains dark. The phases of the moon change as the moon orbits the Earth. Therefore, the changing, relative positions of the sun, moon, and Earth give us the different phases of the moon.

            As the moon progressed through the lunar cycle I noticed that the rise and set time of the moon changed day to day. The changing rise and set time of the moon was noticeably different around the first quarter moon when the moon is around ninety degrees to the left of the sun and lags behind six hours. So, during the first quarter of the lunar phase the moon rises in the middle of the day, high in the south at sunset, and sets in the middle of the horizon at night. Essentially, the two main motions involved, rotation of the Earth and orbit of the moon cause the moon rise and set time to vary from day to day. 

            In order to help students learn why the moon grows (waxes) and shrinks (wanes) I would use a hands-on demonstration to make phases of the moon seem “real” and meaningful. The demonstration would involve whole-group learning time. The instructions for the demonstration used are as follows:

1.     Place small mark on one side of tennis balls (enough for the class) to represent the side of the moon that faces the Earth. Then, give each student a tennis ball.

2.     Turn on a lamp or any light source available in the center of the room to represent the sun and turn off all other lights. Place children in a wide circle around the “sun” facing it. Have each student hold tennis balls at arms lengths at or below the level of the light. Ask them how much of the light is on their side of the tennis ball. The answer should be, “none” representing the new moon.

3.     Instruct the students to turn their bodies slightly to the left, keeping the ball in front of them, until they can see a small crescent shape on the left side of the ball. This represents the new crescent phase.

4.     Have the students make another slight turn to the left until half of the ball reflects the lamplight. This represents the first quarter moon.

5.     Continue this process (turning) until all students have their backs to the lamp. The light will reflect across the entire front of the ball, representing the full moon.

6.     Make two more left hand turns – representing the last quarter last crescent phases – until the children are back in their original positions at the new moon phase.

I think a demonstration would really help the students to visualize the phases of the moon and how it “grows” (waxes) and “shrinks” (wanes). For younger students, kindergarten-aged, I would use the cream filling in Oreos to demonstrate the lunar cycle for the students. Using Oreos would put the lunar cycle into a context kindergarten students could understand.

 

Note: The idea for the demonstration using tennis ball came from an in-class demonstration by Dr. Burns in the UAB SOE.