Moon Phase Simulator
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ust as Earth revolves around the Sun, the Moon revolves around
Earth. The seasons occur at different points in Earth’s orbit
around the Sun. The phases of the Moon occur at different points
in the Moon’s orbit around Earth.
Just as half of Earth is always lighted by the Sun and half is in darkness, half of the Moon is always lighted by the Sun and half is in darkness. In the last activity, you used a model to observe how the revolution of the Moon around Earth causes you to see different portions of
the lighted half of the Moon. In this activity, you will use a computer
simulation that provides a different model for understanding the
phases of the Moon.
CHALLENGE
How does the Moon’s revolution around Earth cause the Moon’s
phases?
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Moon Phase Simulator • Activity 81
MATERIALS
For each pair of students
1
computer with access to the Moon Phase Simulation
For each student
1
Student Sheet 71.1b, “My Ideas About the Day, Year,
Seasons, and Moon Phases: After”
PROCEDURE
Part A: Exploring the Simulation
1. Open the Moon Phase Simulation on your computer.
2. Make sure your
that it is.
POINT OF VIEW
is
TOP VIEW.
If it isn’t, change it so
3. Identify the Sun, Earth, and Moon.
4. Click on ANIMATE and describe any changes that occur. Click on
STOP to pause the motion.
Part B: Observing the Phases
5. Change the POINT OF VIEW to BOTH VIEWS. Make sure your MOON
PHASE is 0.0. If it isn’t, change it by highlighting the number, typing in 0.0. , and pressing RETURN.
6. Look carefully at the objects in the black box. Make a labeled
sketch of them in your science notebook. Title your sketch with a)
the moon phase number and b) the name of the phase.
7. Change the moon phase number to 0.25 , and press the RETURN key.
Make a titled and labeled sketch as you did in Step 6.
8. Repeat Step 7 until you have made sketches for the phase numbers
0.5 , 0.75 , and 1.0 .
9. Click on ANIMATE, and describe what happens. Click on
pause the motion.
STOP
to
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Activity 81 • Moon Phase Simulator
ANALYSIS
1. In the simulation, what do the dark and light halves of Earth and
the Moon represent?
2. Why are the lighter colored halves of the Moon and Earth always
shown facing the Sun?
3. Compare your Part B sketches for MOON PHASE 0.0 and MOON PHASE
1.0 . Explain why these phases have different numbers but look the
same.
4. Compare this computer model to the physical model your teacher
showed you in Activity 80.
a. What are the advantages and disadvantages of using the ball
and light to represent the Moon and Sun?
b. What are the advantages and disadvantages of the computer
model?
5. Write a description and draw pictures that you could use to explain
the reason for the phases of the Moon to a friend.
6. Reflection: How have your ideas about the reason for the phases
of the Moon changed since you began this unit?
EXTENSION
Visit the Issues and Earth Science page of the SEPUP website for links to
information about eclipses of the Sun and Moon.
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