Tune in to the Moon
The
Moon Journal -- Activities
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Workshop
2 -- Measuring
the Moon's Diameter
When
making your Moon observations, take a ruler with you. Hold the ruler
at arm's length from your body and measure the diameter of the Moon
in centimeters. Record your finding and try it again the following night.
Does the diameter of the Moon change every night? Can the diameter of
the Moon really be measured in centimeters with a ruler?
For
more accuracy, you can measure the Moon's diameter using a Cross Staff.
Here's how.
Building
a Cross Staff
Materials:
Cross Staff template, Paste or glue, Cardstock, Meter stick, Scissors
Instructions
- Adhere the Cross Staff template to a piece of cardstock and cut
along the solid lines. Be sure to cut out the notch at the top of
the template and the rectangular slot in the center.
- Push a meter
stick through the rectangular slot and make sure that the card can
move freely up and down the length of the meter stick.
Using
a Cross Staff
- On a night when the Moon is at or near full, hold the meter stick
with the zero end touching your cheek and the meter stick pointing
towards the Moon.
- Slide the
card along the meter stick until the Moon just fills the notch.
(It may be helpful to close one eye while looking at the Moon through
the notch.)
- Note the distance
along the meter stick between the card and the end closest to your
eye.
- You can now
calculate the diameter of the Moon using the following ratio:
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width of notch
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diameter of Moon
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=
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distance from card to eye
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distance to Moon
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Use the distance 400,000 km as the distance from the Earth
to the Moon. (The accepted value is 384,401 km.)
Extensions
Often the Moon looks "bigger" when it is near the
horizon. How could you use a Cross Staff to check whether or not this
is a true phenomenon?
A Cross Staff can be used
to determine the dimensions of other objects once their distance from
the observer is known.
Adapted from:
Hall, J. (1994). Calculating the Moon's
diameter. In N.B. Ball, H.P. Coyle, & I.I. Shapiro (Eds.) A teacher
resource to enhance astronomy education: Project SPICA. Kendall/Hunt
Publishing Co.: Dubuque, Iowa.
Wong, O.K. (1987, October). How wide is
the Moon? The Science Teacher.
[ Back to Top ]
Workshop 3 -- Measuring
the Elevation of the Moon
One
piece of information helpful in describing the Moon's position is its
height in angles (angular height) above the horizon. The horizon is the
line along which the sky and land -- or sea -- appear to meet. You can
determine the Moon's height above the horizon if you know the angle between
the line from your eyes to the Moon and the line from your eyes to a point
on the horizon directly below the Moon.
Measuring
with Fists
You
can estimate the Moon's angular height by simply using your hands. Stretch
one arm out straight and make a fist with the hand on your outstretched
arm. From the horizon to the highest point in the sky is one quarter of
a circle or 90 degrees. If you measure with fists, putting one fist on
top of the other, nine fists will about equal this angle -- one (adult)
fist is roughly the same as 10 degrees.
To measure
the angular height of the Moon at any given time, stretch one arm out
straight and make a fist with the hand on your outstretched arm. Close
one eye and adjust your sight so the outstretched fist is aligned with
the horizon. Make a fist with your other hand and stack it on top of the
first. Continue stacking your fists, one on top of the other, until the
Moon appears to be covered by one of the fists. The number of fists you
stacked indicates the angular height of the Moon. For example, if you
counted six fists, the angular height of the Moon above the horizon would
be approximately 60 degrees.
Measuring
with a Clinometer
A clinometer
is a tool that can help you to measure the angular height of the Moon
more accurately than with your fists.
Materials:Protractor
template, Cardstock, Paste or glue, Drinking straw, Clear tape, Scissors,
30 cm fishing line or kite string, Metal washer or weight with hole, Tack
or pin
Building
a Clinometer
- Adhere the protractor template to a piece of cardstock and cut along
the dotted lines.
- Center the straw lengthwise along the edge of the template directly
above the straight side of the protractor. Secure it in this position
with tape.
- At the point where the protractor's center line (0 degrees) meets
with the line that runs parallel to the straw, use a tack or pin to
make a hole.
- Thread one end of the fishing line or kite string through the hole
so that approximately 2 cm extends out the back side of the protractor.
Secure this portion of string to the back side of the protractor.
- Tie the metal washer to the opposite end of the fishing line or
kite string. The string and washer should swing freely along the front
side of the protractor.
Using
a Clinometer
- Position the Clinometer straw-side up so the straw is parallel
to the ground and the string hangs parallel to the 0 degree marking
on the protractor.
- Look through the straw and adjust the position of the Clinometer
until you sight the horizon directly below the Moon (while keeping
the straw parallel to the ground).
- While looking through the straw, tip the entire Clinometer upward
until you can sight the Moon through the straw.
- As you move the Clinometer, the string moves along the protractor.
By noting the position of the string along the protractor, you can
determine how many degrees you are tipping the Clinometer to sight
the Moon. This measurement is the angular height of the Moon.
Extensions
To measure
the height of an object that makes a right angle with the land, such as
a tree or a building, sight the top of the object through your clinometer
and walk towards the object until the clinometer measures 45 degrees.
By mentally tracking from your observation point to the base of the object
to the top of the object and back to your observation point, you will
make an isosceles triangle. Given that two sides of an isosceles triangle
are equal, you can determine that the distance from the observation point
to the object itself will be equal to the height of the object.
Adapted
from:
Coyle,
H.P., Gregory, B., Luzader, W.M., Sadler, P.M., & Shapiro, I.I. (1993).
Project STAR: The universe in your hands. Kendall/Hunt Publishing
Co.: Dubuque, Iowa.
Education
Development Center, Inc. (1968). Where is the moon? Webster Division,
McGraw-Hill Book Co.: New York.
[ Back to Top ]
Workshop
4 -- Sun, Earth,
and Moon Angles
One
way to chart the Moon's behavior is to chart its position with respect
to the Sun and the Earth. Specifically, you can measure the angle between
the Moon and the Sun, with the Earth as the vertex of the angle.
At a
time when both the Moon and the Sun are visible measure the angle between
the Moon and the Sun from your observing location. Each time you measure
and record the angle, also observe and record the shape (phase) of the
Moon, and notice whether the lit or unlit portion of the Moon is nearest
the Sun.
CAUTION:
Never look directly at the Sun.
Estimating
Angles with Fists
Just
as you can use fists to measure the elevation of the Moon, you can do
the same to measure the angle between the Sun and the Moon. Make a fist
with each of your hands and hold them out in front of you at arm's length.
Count how many fists make up the distance between the Moon and the Sun.
Measuring
Angles with a Protractor
Materials:
Clinometer
Instructions
- Position your
clinometer with the protractor numbers face-up.
- Point one end
of the straw to the Moon.
- Slide the string
along the top of the protractor until it is aligned with the direction
of the Sun.
- Use the numbers
along the side of the protractor to calculate the angle between the
Sun and the Moon.
Questions
- Is the lit
or unlit part of the Moon facing the direction of the Sun?
- Which direction
are the "horns" of a crescent facing with respect to the Sun?
Does this change as the angle between the Moon and the Sun changes?
- Do you notice
a pattern between the Moon-Sun angle and the phases of the Moon?
[ Back to Top ]
Workshop 5 -- Modeling
the Phases of the Moon
To do this activity
effectively, the room must be as dark as possible. Darken the room by
closing the blinds and covering all window and door cracks with black
paper or cloth and tape.
Materials: Lamp,
Extension cord, Clear light bulb (75 watts or more), 3-inch Styrofoam
ball, Craft stick
Instructions
- Make a "handle" for your Styrofoam ball by carefully pushing
a craft stick into the ball. Hold the handle so the Moon ball is positioned
upright.
- You will be part of a model that portrays the phases of the Moon.
In the model, your head will represent the Earth, the Styrofoam ball
will represent the Moon, and the lamp will represent the Sun.
- Place the lamp in the center of the room and turn it on. Turn off
the room lights and then stand approximately two arm-lengths away
from the lamp.
- Hold the Moon ball directly in front of the lamp and at arm's length
from your body, pointing upwards approximately 45 degrees. Notice
that as you hold the Moon ball in front of your body and turn around,
sometimes part of the ball is lit, and sometimes the whole hemisphere
facing you is lit.
- Keep turning until you can see a thin crescent lit up on the Moon
ball.
- Continue moving in the same direction until the Moon ball looks
like a half-lit circle.
- Continue moving in the same direction until the ball looks completely
lit.
Questions
- Is the brightest side of the Moon facing towards or away from the
Sun?
- For the Moon to appear "fuller," how does it have to
change its position relative to the Sun?
- When the Moon is full, is it on the side of the Earth that's closest
to the Sun, or the side that's farthest away from the Sun?
- Are the phases of the Moon the same in the northern and southern
hemispheres?
Extensions
On a sunny day
when the Moon is visible, go outside with your Styrofoam Moon ball.
Stand facing the Moon, holding out your Moon ball at arm's length "covering"
the Moon in the sky. The Sun will shine on the ball and illuminate it
exactly as it illuminates the Moon.
Adapted from:
Foster, G.W. (1996). Look to the Moon. Science and
children. 34(3), 30-33.
Braile, S. (1994). Moon phase modeling. In N.B. Ball,
H.P. Coyle, & I.I. Shapiro (eds.), Project SPICA. Kendall/Hunt
Publishing Co: Dubuque, Iowa.
[ Back to Top ]
Workshop
6 -- Observing
the Features of the Moon
Sketching Features
of the Moon
Materials:
Pencil, Paper, or sketch pad, Binoculars (optical), Moon
Map
Instructions
Before using the
Moon Map to identify features on the Moon, sketch the features you observe.
When the Moon is not full, you should notice that the Moon is divided
by a line -- the terminator line -- that separates the Moon's sunlit side
from its shadowed side. The features on the Moon's surface stand out best
near the terminator line. These features are even more apparent when using
high-powered binoculars. Use your Moon Map to help identify interesting
features on the Moon.
To observe a feature
on the Moon over time, use your Moon Map to identify a feature close to
the "curved" edge of the lit portion of the Moon. Examine this
feature over a week or two. Is the feature always visible? Does the feature
change its relative position? Does the feature seem to "move" across
the Moon or stay in the same place?
Challenge
How do your observations
help you to learn something about the revolution time of the Moon as compared
with the rotation time of the Moon?
[ Back to Top ]
Workshop
7 -- Moon Phase
Guide
If you know the directions in which the Moon rises and sets, a Moon Phase
Guide is a useful tool for determining the time at which the Moon rises
and sets.
Building a Moon
Phase Guide
Materials:
Moon Phase Guide template, Corrugated
cardboard (15 cm x 15 cm), Pushpin or thumbtack, Almanac, newspaper, or
calendar, Scissors, Glue or paste
Instructions
- Cut out both
pieces of the Moon Phase Guide.
- Glue or paste
the larger piece to the center of the cardboard.
- Orient the smaller
piece on top of the larger such that the center points are aligned.
- At the center
point, push a pushpin or thumbtack through both template pieces and
the cardboard.
Using a Moon
Phase Guide
- Determine the current Moon Phase (consult an almanac, newspaper or
calendar).
- Position the Moon Phase Guide so that the text is face-up and parallel
to the ground.
- Holding the half-circle in place, rotate the cardboard until the current
Moon phase is directly under the Moon Rise portion of the half-circle.
- Note the time the arrow on the half-circle is pointing to. This is
about the time the current Moon phase rises.
- Next, rotate the cardboard until the phase of the current Moon phase
is directly under the Moon Set portion of the half-circle.
- Note the time the arrow on the half-circle is pointing to. This is
about the time the current Moon phase sets.
Questions
- The Moon Phase Guide indicates that the Moon is visible for 12 hours
each day. Is this accurate?
- Why is there a predictable pattern to the changing appearance of
the Moon?
- How does the Moon Phase Guide work? What assumptions does it make
about the Sun-Moon-Earth relationships in its design? What assumptions
does it make about the directions of Moon rise and set.
Adapted
from:
Becker,
K. (1994). Moon phase dial. In N.B. Ball, H.P. Coyle, I.I. Shapiro (Eds.)
Project SPICA.Kendall/Hunt Publishing Co:Dubuque, Iowa.
[ Back to Top ]
Workshop
8 -- Moon Legends
Our scientific understanding
of the Moon and its behavior has not always been what we currently accept
to be true. Throughout history and across cultures, civilizations have
developed what we know of today as legends and folklore as explanations
of Moon observations and its behavior. Legends were the first scientific
explanations. People would observe a phenomenon and then describe it with
a story. People eventually began comparing different legends of similar
phenomenon to find out which were most helpful in explaining what they
saw. The following are stories developed by early cultures to describe
possible reasons for the behavior of the Moon:
According to Central
Mexican (non-Mayan) cultures, the Moon and the Sun were created at
the same time when the two gods, Tecuciztecatl and Nanahuatzin threw themselves
into the Fires of Creation and turned into two Suns. But the gods who
organized this also threw a rabbit into the face of Tecuciztecatl, dimming
his brightness, making him the Moon.
The Mayans
believe the Moon Goddess to be a feisty woman. It is said that she once
quarreled with her husband, the Sun, who became so angry that he poked
out one of her eyes. That is why the Moon Goddess is dimmer than her spouse
the Sun.
The Cherokee tribe
of California tells the story of Father Sun and Mother Moon who lived
inside Rock House. Their light did not shine from the sky, so the world
was full of darkness. Coyote thought it would be a fun trick to dump some
fleas on Father Sun and Mother Moon. Coyote got Gopher to help dig a hole
through the soil into Rock House, and Rabbit to help shake a bag of fleas
down the opening. The fleas soon covered Father Sun and Mother Moon. When
they could no longer stand the fleas, Mother Moon flew out of the house,
followed by Father Sun, and they began to race around the Earth trying
to get rid of the fleas. That is why, to this day, the Sun follows the
Moon across the sky.
The Snoqualmie
tribe in Washington tells the story of a time when the sky was completely
dark and there were two brothers, One Who Walks All Over the Sky, and
Walking About Early. One Who Walks was sad to see the sky always dark
so he made a mask out of wood and lit it on fire. Each day he walks across
the sky wearing his fiery mask. At night he sleeps below the horizon and
when he snores sparks fly from his mask and make stars. The other brother
became jealous. He smeared fat and charcoal on his face, and makes his
own path across the sky.
The Zunipu tribe
of New Mexico and Arizona tells a story of a time when it was always
dark, and always summer. Coyote and Eagle were hunting and they came across
a tribe that had the Sun and the Moon in a box. After the people of the
tribe had gone to sleep, the two animals stole the box. At first Eagle
carried the box, but soon Coyote convinced Eagle to let him carry it.
Coyote, being curious, opened the box and the Sun and the Moon escaped
and flew up into the sky. This gave light to the land, but it also took
away heat, which is why we now have winter.
Questions
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