Replacement p. 46-50, Lab D, Moon
B. Getting oriented in the sky
1. Set up your Sun-Earth-Moon system as follows, referring to the picture as necessary.
- Clamp the Sun to the lab table, if needed.
- Rotate the large ELONGATION wheel so that the Sun is at 0 .
- Place the Earth on the small HOUR ANGLE wheel,
with Minnesota facing 0 (= South).
- Rotate the Hour Angle wheel so that the Sun is directly opposite South,
as seen from MN.
- Place the Moon at 180 on the ELONGATION wheel.
2. Refer back to the Moon Project description in the lab book, and write down a
description of where the Meridian is on your apparatus. (picture yourself on the Earth)
IGNORE THE ELONGATION WHEEL AT THIS POINT
Rotate the Hour Angle wheel 90 degrees counterclockwise. Now describe where the
Meridian is on your apparatus.
Your TA may want to check your description of the Meridian before going on.
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Replacement p. 46-50, Lab D, Moon
For the rest of the lab, assume that the Sun crosses the Meridian at noon.
3 Rotate the Hour Angle wheel so that the Sun is again directly opposite South.
What is the Hour Angle of the Sun, as seen from MN? ____________
What time is it in MN? ___________________
Rotate the Hour Angle wheel forward in time until the Sun rises in Minnesota..
Viewed from above, did the Earth rotate Clockwise ______ or Counter Clockwise_____
What is the Hour Angle of the Sun now? _____________
What time is it in MN now? _____________
Rotate the Hour Angle wheel further CCW until the Sun sets in Minnesota.
What is the Hour Angle of the Sun now? _____________
What time is it in MN now? _____________
4. Use the numbers above for change in Hour Angle and change in time, to calculate
how many degrees the Earth rotates every hour ___________
Since we know the Earth rotates 360 degrees every 24 hours, how many degrees
should the Earth have rotated every hour? __________
C. Bring on the Moon
1. Make sure that the Moon is in the 180d position in the Elongation Wheel. The
Elongation wheel tells you how far apart the Sun and Moon are in the sky.
2. Rotate the Earth forward in time by 6 hours.
What is the Elongation angle of the Moon now? ___________
How did the Elongation change? Why? __________________________________
______________________________________________________________________________________
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Replacement p. 46-50, Lab D, Moon
3. Rotate the Earth CCW until the Moon just becomes visible in MN.
What is the Hour Angle of the Moon ? _______________
NOTE - THIS IS WHAT YOU WILL MEASURE WITH YOUR FIST!
EACH PERSON SHOULD PICTURE THEMSELF ON EARTH,
AND MAKING THE MEASUREMENT. IT WILL HELP A GREAT DEAL!
What is the Hour Angle of the Sun ? ________________
The Elongation of the Moon is how far apart the Sun and Moon are in the sky. It can be
calculated as follows:
Elongation = Hour Angle of Sun – Hour Angle of Moon
Using this formula, what is the Elongation __________
(If Elongation is negative, add 360o. If Elongation is greater than 360o, subtract 360o)
How does it compare to the value on the Elongation wheel? ________________
4. The Moon rotates around the Earth counterclockwise in approximately 28 days.
Move the Moon to where it will be approximately 1 week from its present position.
Rotate the Earth so that the Moon is directly South as seen from MN.
What is the Hour Angle of the Moon ? _______________
NOTE - THIS IS WHAT YOU WILL MEASURE WITH YOUR FIST!
What is the Hour Angle of the Sun ? _______________
Calculate the Elongation using the formula above ______________ and
compare it to the Elongation wheel value. Do they agree?
D. MOON PHASES
Note: everyone in the group must look at the Moon’s phase for each of the
experiments below. To observe the Moon’s phase, you must physically move so
that the Earth is directly between you and the Moon. This simulates what you
would see if you were viewing the Moon from the Earth.
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Replacement p. 46-50, Lab D, Moon
When you sketch the Moon for this lab, and for the Moon Project, color in the
dark region of the Moon dark, and leave the light side of the Moon light.
PHASE NUMBER
1. Place the Moon at 180 degrees Elongation. Rotate the Hour Angle wheel so the
Moon is directly South.
Standing with the Earth between you and the Moon (each person), and using the phase
number diagram above, what is the Moon’s phase number? __________
What name do we use for this phase ____________
Rotate the Hour Angle wheel so that the Moon is at 45 degrees as seen from MN.
What is the phase number now? _____________
How does the phase of the Moon change with the time of day in MN?
________________________________________________________
2. Place the Moon at 0 degrees Elongation. Stand with Earth between you and Moon.
What is the phase number ? _____________
What is the phase name? ______________
E. PUTTING IT ALL TOGETHER
Use the apparatus to set up each of the experiments on the following page.
Start by moving the Moon to the correct elongation.
Then rotate the Earth’s Hour Angle wheel so that the Moon is visible from MN.
Vary the Hour Angle of the Moon for each experiment.
Rotate the Earth as needed to determine the Rise and Set Time of the Moon.
When the chart is complete, print names on first line, signatures on 2nd line.
________________ __________________ ________________ _____________
________________ __________________ ________________ ____________
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Replacement p. 46-50, Lab D, Moon
ELONGATION
Drawing
view from Earth
Phase
Name
Sun Hour
Angle
Moon
Hour
Angle
Calculated
Elongation
Rise
Time
Set
Time
180 degrees
215 degrees
270 degrees
315 degrees
0 degrees
45 degrees
90 degrees
135 degrees
WHEN COMPLETE, PUT AN ASTERISK IN THE ELONGATION COLUMN IF THE MOON IS VISIBLE BETWEEN Noon-6pm
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