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Aerospace
Activity for April, 2000 |
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The
Potato
Asteroid
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Objective
The objective is to carefully measure the
size and shape of an "asteroid" potato. Students and cadets are required
to use their imagination to observe and record precise calculations. A potato is
used because of its irregular shape. The collected data can be compared to known
data about actual asteroids.
Time Requirement
About an hour
Materials
Each student will need the
following:
- Potato
- Metric Ruler
- Art Paper
- Pencil
- A dunking Measuring Cup (may be shared)
- A large metric measuring cup or graduated
cylinder - marked in Milliliters (may be shared)
- A Scale in Ounces (may be shared - Metric is
preferred)
- String
- Water
- Calculator
- Colored Markers
Background
- Between the orbits of Mars and Jupiter, the
observer will find literally thousands of small planets known as asteroids.
When these chunks of debris enter our atmosphere, and hopefully burn up, they are
known as meteorites. Sometimes when asteroids in the Mars/Jupiter orbit collide,
they break orbit and move elsewhere, often towards Earth. One asteroid, known as
Gaspra, became the first to be photographed close up by the Jupiter bound spacecraft
Galileo. Another asteroid, observed by Galileo, was found to have its own tiny moon.
It is called IDA, a name that honored the state of Idaho. Ida is shaped much
like a typical Idaho potato and, using your imagination, this activity will set about
investigating the asteroid "lookalike". Ida is 52 kilometers long
(approximately 32 miles) and appears to have a magnetic field. Its moon is known as
Dactyl.
- Recently, another
NASA spacecraft entered obit around the asteroid named
EROS. This NASA project is known as the Near Earth
Asteroid Rendezvous (NEAR). The NEAR website is updated
frequently with new information collected by the NEAR project. Follow
this link to NEAR (Note:
this link will leave this site) to view recent data.
There are larger photos there that can be printed, or
if your unit has access to the internet they can be observed
on-line. Some teaser images of Eros from the NEAR
website are presented below:
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Asteroids Mathilde at left,
and Eros at Right |
Eros in Color
(Is that a potato, or what?) |
Procedure
- Each student should first sketch their
asteroid potato. Have them draw in shadows to create an appearance of the overall
contour as seen in the NASA images.
- Each cadet should give their asteroid a name
and refer to it by this name throughout this exercise.
- The asteroid potato should be weighed and the
data recorded.
- Wrap a string around the length and width of
the asteroid potato and then measure the length of the string to get length and width
circumferences. Record the data.
- It's time to check volume. Fill the
dunking cup completely full of water. Pour all of the water into the measuring cup.
Have all of the cadets record the initial amount of water in the dunking cup.
- Pour all of the water back into the dunking
cup.
- Make sure that the cup is completely full for
each cadet at this step. Have the cadet carefully dunk the potato in the measuring
cup so that it is completely below the surface of the water. Hold it down with a
pinky if needed. (This will make a mess, but that's part of the fun!)
- Remove the potato, and record the amount of
water left in the cup by pouring the remaining water into the measuring cup.
Subtract the amount left from the amount that was originally in the cup. That is the
volume of the asteroid. Record the data.
A sample Asteroid Data Fact Sheet is presented below. You may be able to cut
and paste this table from the web page, or you may make your own. Each student
should record their observations on the fact sheet.
Cadet Name: |
Asteroid Name: |
A |
Circumference Length: |
(in centimeters) |
B |
Circumference Width: |
(in centimeters) |
C |
Weight: |
(grams? Ounces?) |
D |
Starting Water: |
(ml) |
E |
Remaining Water: |
(ml) |
F |
Fluid Volume of the Potato: |
(subtract E from D) |
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("F" is also volume
in cubic Centimeters!) |
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Discussion
Challenge the students with the
question "How would scientists measure an asteroid using different methods?"
Also ask "What can we learn from studying asteroids?" Another good
question is what observations can we perform with a potato that would be very difficult to
do in space?
This activity was inspired by Dr. Lynn
Bondurant, Education Programs Officer at NASA/Lewis Research Center in Cleveland, Ohio
Adapted from: Aerospace 2000, Volume 5
Published by the Aerospace Education Training Directorate
National Headquarters, Civil Air Patrol.
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