How to Make a Rubber Band Propelled Car

Rubber bands can be used to power a toy car.

Rubber band toy cars are one of the simplest self-propelled toy cars that you can make at home. It is a simple process that takes about an hour. The car operates due to the stored (potential) energy created by wrapping the band around the axle, changing into motion (kinetic) energy as it unwraps. The longer the rubber band you use, the faster and farther your car will be able to go. Also, by changing the size of the wheel you can affect distance and speed, so try different combinations, and have fun.

Things You'll Need

• 5-by-6 inch piece of corrugated cardboard (the holes formed by the corrugation need to be visible along the long edge)
• Ruler
• Scissors
• Wooden skewer (The thinner, the better. Preferably around 1/8 inch.)
• Tape (duct or masking will work)
• Two Faucet washers (¼ inch, large)
• Two CDs
• Poster putty (¼ package)
• Rubber band
• Art supplies (for decoration)

Instructions

1. Notch the body. Using the scissors, cut a notch in the center of the 5-inch side of the cardboard. The notch needs to be 1½ inches deep and 2 inches wide. Throw away the piece that you cut out.

2. Make the axle. Slip the wooden skewer through the cardboard, near the outer edge of the notch. The skewer must be equally distributed on either side of the cardboard, or the car will drive crooked. If the skewer doesn't rotate freely, turn it manually a few times to widen the opening a little bit.

3. Modify the axle. In the middle of the section of skewer that is in the middle of the notch, wrap a small piece of tape to create a "catch" for the rubber band. To make sure that the catch is thick enough to support the band, twist the tape that is sticking up.

4. Assemble the wheels. Place and hold a washer in the middle of the CD's center hole. Slip the CD with the washer onto the skewer on one side of the cardboard, leaving lots of room between the CD and the cardboard. Apply poster putty generously to both sides of the washer to join the CD, the washer, and the skewer very tightly. Test to see if the wheel and axle spin together, if so, repeat this process for the second wheel, if not, pack the putty tighter.

5. Attach the rubber band. Tape one end of the rubber band to the cardboard cut out. It needs to be taped to the end opposite of the axle.

6. Power the car. Wrap the loose end of the rubber band around the catch. Rotate the axle several times, winding the rubber band around the axle. When the rubber band unwinds, it will propel the car forward.

References

• PBSKids: Rubber Band Car Project