TOPIC: Newton's Third Law of Motion
OBJECTIVE: To construct a car to demonstrate how rockets move
by means of action and reaction.
DESCRIPTION: A small car is propelled by the action/reaction
force generated by a balloon.
CONTRIBUTED BY: Gregory Vogt, OSU
EDITED BY: Roger Storm, NASA Lewis Research Center
MATERIALS and TOOLS:
- 4 pins
- Styrofoam meat tray
- Cellophane tape
- Drawing Compass
- Marker pen
- Small party balloon
- Emery Board
- Using the ruler, marker, and drawing compass, draw a rectangle 3 by
7 inches and four circles 3 inches in diameter on the flat surface of the
meat tray. Cut out each piece. Use an emery board to make the wheels as
round as possible.
- Push one pin into the center of each circle and then into the edge
of the rectangle as shown in the picture. The pins become axles for the
wheels. Do not push the pins in snugly because the wheels have to rotate
freely. Test them to be sure they rotate freely. It is okay if the wheels
- Inflate the balloon a few times to stretch it out a bit. Slip the nozzle
over the end of the flexi-straw nearest the bend. Secure the nozzle to
the straw with tape and seal it tight so that the balloon can be inflated
by blowing through the straw.
- Tape the straw to the car as shown in the picture.
- Inflate the balloon and pinch the straw to hold in the air. Set the
car on a smooth surface and release the straw.
DISCUSSION: The rocket car is propelled along the floor according
to the principle stated in Isaac Newton's third law of motion. "For
every action there is an opposite and equal reaction." The balloon
pushes on the air and the air pushes back on the balloon. Because the balloon
is attached to the car, the car is pulled along by the balloon.
BACK TO THE ROCKET ACTIVITIES
Oklahoma State University