In this activity you will
build and investigate the rubber band motor. Then, you will
use this motor to power a vehicle you create. Through tweaks,
tests, and changes, you'll improve the design to attain the
most efficient and longest-traveling cart.
activity page will offer:
in the transfer of energy
to construct self-propelled vehicles
arena in which to design, create, test, and improve a
to construct an understanding of design evolution
- rubber band
- metal washer
- paper clip
- cotton swab
1 - A RUBBERBAND MOTOR
- Insert a rubber band through the hole in the middle
of a thread spool. Make sure that the ends of the rubber
band stick out from both ends of the spool.
- Insert a paper clip through one of the exposed rubber
- Use tape to secure this clip to the side of the spool.
- Insert the other exposed end of the rubber band through
a metal washer.
- Pull the loop through the washer. Then, stick a cotton
tipped swab through the loop.
- Wind the swab. As you turn it, the rubber band will
- Once enough tension has been wound into the rubber band,
place the spool on a flat surface.
- Release your hold on the spool and swab. What happens?
- Try different variables to see if you can increase the
You may have to tweak your design using a different
size spool, larger or smaller rubber band, or strips of
sand paper that will increase the friction between the spinning
spool and the floor.
- What happens when you release the wound-up rubber band?
- Starting with the sun, describe the energy transfers
that occur in order to get the spool moving.
- What form of energy is being stored before letting go?
- What energy transformation occurs when you let go?
- Where does the energy of the spinning spool go?
2 - A SELF PROPELLED VEHICLE
- spool motor you built in part 1
- paper clips i
- Use scissors to cut out a rectangular cardboard frame
that is exactly 4 inches wide by 6 inches long.
NOTE: If the class is using metric measurements, the vehicle
dimensions should be simplified to 10 cm wide by 15 cm
- Cut out four circular wheels. The wheels can be any
- Straighten out one bend in a paper clip to form a shaft.
Tape the looped portion of the clip to the cardboard chassis.
Make sure that straight piece of the clip projects beyond
the side. Slip the wheel over this axle. To keep the wheel
from falling off, you may need to bend up the end of the
clip or add a hub of clay.
- Cut out a window in which to "drop in" you spool engine.
- To propel this vehicle, wind up the spool engine.
- Drop in the engine and release the spool. What happens?
your chance to think like an engineer. How would you improve
the design of this vehicle to increase the distance it travels?
To help define these possibilities, first brainstorm a list
of all the different things that you can change. Then, using
whatever parts are available, build a racer that will test
your thoughts. Keep improving the design until you get a
spool that travels the furthest distance.
improving their design, one team used sandpaper to "rough
up" the rims of the spool that made contact with the ground.
This strategy worked! The spool traveled nearly twice as
far. Can you explain why the rough surface was a more efficient
wheel than the original spool edge?
you are in charge of designing three robotic spacecrafts.
Each craft will explore the surface of only one planet.
Your job is to design a self-propelled craft that can send
back data about this alien world. Since cost control is
essential, design one craft with special modules that can
be adapted for each environment.
three planetary environments are:
- Planet covered by a shallow ocean of water.
- Planet with a quick-sand like surface.
- Planet with extreme temperature range and hard rock
- With a classmate, brainstorm all of the parameters that
need to be considered in the development process. Identify
what needs are common to each of the three robots. How
will can these needs be met with the same module? What
special considerations are needed for each robot? How
will the robot design be customized for each mission?
- Once you have thought out your design, produce the blueprints
for these three vehicles.
- Using simple art materials, construct one of the three
- How would you sell your ideas? Present your model and
blueprints to your classmates as if they were a panel
looking into funding your project.
robots of the week!
robots built by University of Edinburgh in Scotland.
Minds-On" and "Self-Propelled Learning" were contributed
by Michael Dispezio, a Massachusetts-based science writer
and author of "Critical Thinking Puzzles" and "Awesome Experiments
in Light & Sound" (Sterling Publishing Co., NY).