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NOVA scienceNOW: Space Elevator
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Viewing Ideas
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Before Watching
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Familiarize students with terms related to the space
elevator.
Have student pairs find the definitions for the following terms
in their textbook, on the Internet, or from another resource.
geosynchronous orbit: When a satellite orbits 22,000
miles above Earth's surface, it travels at a speed that allows
it to stay in the same position relative to Earth.
prototype: An experimental working model of something
that is typically used to base future models on.
buckyball: An informal name for buckminsterfullerene, a
form of carbon composed of 60 atoms. A molecule of
buckminsterfullerene looks similar to a round soccer
ball—thus the name "buckyball." The molecule is named for
Buckminster Fuller, an architect, author, and inventor who
designed a structure—the geodesic dome—that looks
much like the carbon molecule.
carbon nanotubes: Nanotubes are cylindrical forms of
carbon with novel properties. They are good conductors of heat
and electricity and have extraordinary strength, far greater
than steel.
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Explore carbon in everyday life. Carbon is the most
versatile element in the periodic table. It is the foundation of
organic chemistry and is the basic element in plant and animal
cells. It is an essential component of plastics and many
pharmaceuticals.
Divide the class into three groups. Assign each group one of the
sets of carbon compounds below to research. When they have
completed their research, have each student group make a poster
and present what they learned to the class.
Group 1: Diamonds, coal, graphite
Group 2: Oil, natural gas, plastics, pharmaceuticals
Group 3: Proteins, fats, carbohydrates
As an extension, ask students to research how or why carbon can
exist in such dramatically different forms, colors, and
characteristics.
(Carbon has four bonding positions in its outer electron
shell and is unique in its ability to form double and triple
bonds. Carbon can form incredibly complex chain molecules,
rings, sheets, lattices, buckyballs, and tube structures.
There are more types of compounds formed with carbon than with
any other element.)
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Calculate and compare scale distances. The carbon
nanotube space elevator would transport materials into
geosynchronous orbit around Earth. How does the distance of this
geosynchronous orbit compare to the distance of space explored
by a space shuttle? Give students the Size and Distance Stats
below and have them calculate, then show, the scale of the two
orbits.
(Students should calculate map scale first. For example, if
the globe is 10" in diameter and Earth's diameter is 8,000
miles, then 1" = 800 miles. The space shuttle would orbit only
1/4 of an inch above the globe's (Earth's) surface. A
satellite in geosynchronous orbit, or the final stop of the
space elevator, would be 28" above the globe.) Now have students use sheets of paper to make models showing
the scale. Place the sheets side by side for comparison.
Size and Distance Stats
Earth is represented by a 10" globe (or use whatever size globe
you have)
actual diameter of Earth = 8,000 miles
space shuttle orbit = use an orbit of 200 miles above surface of
Earth ( Note: The space shuttle's orbit ranges from 115 to 250
miles.)
geosynchronous satellite orbit = 22,000 miles above surface of
Earth
After Watching
Explore the materials needed for making carbon nanotubes (Part 1),
then compare the theoretical model of the space elevator to actual
models (Part 2). (These two parts can be completed individually or
as sequential activities.) As students watch the program segment,
have them note the materials needed for building a space elevator,
how the space elevator is constructed, and the components of the
prototypes.
Part 1
Help ground students' thinking about the possibility of building a
space elevator. Ask students to review notes they took while
watching the program segment and answer the following questions:
Which of these components/materials would be the most difficult to
obtain? Which are readily available?
(The space elevator is a theoretical construct
only. The longest carbon nanotube—the main component of a
space elevator—that has been produced so far is a few
centimeters in length. Every other component for a space elevator
is available and in use today.)
Part 2
Have students compare what they learned about the structure of the
space elevator with the prototypes shown in the NASA Space Elevator
contest. Using the notes the students took, develop a list of the
components on the board. Ask students to consider which parts of the
contest's prototype models corresponded to parts of the theoretical
space elevator.
(A steel cable represented the proposed carbon nanotube. The
prototypes all used climbers with motors very similar to one that
could be used in an actual space elevator. As with the theoretical
space elevator, contestants had to shine lights (instead of a
laser) to illuminate the photovoltaic cells that supplied power to
the motors. The top of the crane represented the satellite in
orbit, and the base of the crane was the platform at sea.)
You may want to have students make drawings of what a space
elevator would look like if it could be constructed. Have them label
the satellite in geosynchronous orbit, the cable that stretches from
the satellite to a platform at sea, the climber with motors that
"crawls" along the cable that lifts the loads, the laser beams that
power the motors in the climber, and so on.
Web Sites
NOVA scienceNOW
www.pbs.org/nova/sciencenow/3401/02.html
Offers space elevator related resources, streamed video, and a "Why
Build It" and "Ask the Expert" section.
Carbon Nanotubes
www.personal.rdg.ac.uk/~scsharip/tubes.htm
A concise history and description of carbon nanotube science and
technology and a good list of references.
Space Elevators
science.howstuffworks.com/space-elevator.htm
Provides a simple description of how space elevators will work.
Books
Chemistry
by Ann Newmark and Laurie Buller. Dorling Kindersley, 2005.
Includes information about the chemistry of carbon.
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