Investigation 2 – Lab
This Investigation is designed to:
- contribute to your visual understanding of the phases of the Moon,
- illustrate the effect the rotation of the Earth has on the phases of the Moon,
- illustrate the effect of the revolution of the Moon on the phases of the Moon, and
- allow you to form a mental model of the position of the Sun in relation to the Earth and the Moon.
Student Preparation for the Investigation includes having students gather the following materials. This preparation takes place on lab day after student lab groups have settled at their assigned lab tables.
Note: The materials are listed in students’ SDRs. They are also listed below for your reference.
- (1) moon ball
- (1) student globe
- (1) meter stick
- (1) flashlight
- (5) pieces of tape, approximately 3 cm in length
Direct one student from each lab group to collect the materials listed in their SDRs.
- During this Investigation, you will create a model of the Earth, Sun, and Moon to determine why we observe different phases of the Moon and to determine whether our observations are related to the motion of the Moon, the Sun, or the planets.
- Reflect on the PreLab video as you move through the procedural steps.
- During the Experiment, every procedural step is important. If one step is skipped, data can become invalid. To help you keep on track, read each step thoroughly, complete the step, then check it off (Read it – Do it – Check it).
- Complete all of the procedural steps in your SDR.
Note: The procedural steps are listed below for your reference. “Notes” are inserted, as needed, to help you.
- In this investigation, the movement of the Moon’s phases will be modeled. One student in the group will represent the Earth, one will represent the Moon, and one will represent the Sun.
- Why can the different phases of the moon be observed from the Earth?
- The student representing the Moon should hold the moon ball directly in front of his/her torso, the student representing the Sun should hold the flashlight, and the student representing the Earth should hold the globe.
- Place a stool in the center of a small area in your classroom. The student representing the Earth should sit on the stool, holding the globe.
Note: Remember that although the Earth is located in the center of your model, the Sun is at the center of the solar system. If the model involved the complete movement of the Moon, Sun, and Earth, the Sun would be located in the center. Remember that the Earth rotates on its axis constantly and continuously revolves around the Sun.
- Place four pieces of tape on the floor, each approximately 0.5 m from the chair. Label the four pieces of tape, consecutively A, B, C, and D. Place the tape in a circle around the chair, counterclockwise, in order from A through D (see picture).
- The student representing the Moon should stand on the piece of tape labeled A, facing toward the Earth. The person representing the Sun will join later.
- Place the fifth piece of tape on the side of the moon ball facing the Earth. This marks the near side of the Moon.
Trial 1: Model the rotation of the Earth and the revolutions of the Moon
- The student representing the Earth should rotate on the stool seven times.
- As the Earth performs its seven rotations, the student representing the Moon should slowly move counterclockwise toward the tape B. The tape on the moon ball should always face toward the Earth.
- By the time the Earth finishes its seventh rotation, the Moon should be standing on the tape B, having completed one-quarter of a revolution.
- Repeat steps 7 through 9 until the student representing the Moon is standing on tape D.
- How much time passes as the Earth completes one full rotation in our solar system?
- How much time passes as the Moon completes one-quarter of a revolution around the Earth?
Trial 2: Model how the Sun affects the Moon’s appearance
- The student representing the Sun should move to stand directly behind the Moon and opposite the Earth, directing the flashlight toward the Moon.
- Observe how the light from the flashlight shines on the Moon and how the Moon would appear from the Earth. Repeat these steps at each Tape position.
Note: You will start in the position that models the New Moon, or the position in which no Moon is visible from Earth. In this position, the flashlight will shine on the back of the student representing the Moon, and the lit face of the Moon will not be visible to the student who represents Earth.
Note: The student representing the Earth may need to explain to the group what he/she observes.
Note: Record your observations in Table A of your Investigation Two Data Sheet. As you record your observations, you should color in the area of the moon with a pencil that represents the light from the Sun.
Be sure to clean up after the experiment.