Drag Racer

Rubber band cars are a fun and effective way to teach students about energy transformation from potential to kinetic energy. One of the key points to a successful rubber band car is large wheels with a rubbery texture to allow for friction between the floor and wheels.

This project is recommended for grades four and up. However, this does not limit it to younger age groups, and they may need more help and supervision when building.

Tools:

• Hot glue gun and glue sticks
• Power Drill
• Scissors

Materials:

• (17) Popsicle Sticks
• (6) Craft cubes
• (2) Craft wheels (Back Wheels)
• (4) Bottle Caps (Front Wheels)
• (2) Plastic straws
• (2) Dowels
• (1) Zip tie
• Rubber Bands

For the two back wheels, drill a hole in the center of each wheel.

For the front wheels, drill a hole in the center of only two caps. Important: It is recommended to have an adult supervise the use of the drill.

Create a frame that is two popsicle sticks long with three popsicle sticks jointing either side (Picture 1). This will be the bottom frame.

Glue on the craft cubes as shown in picture 2. Important: Notice in picture 2 that the craft blocks aren't entirely at the very end of the popsicle sticks. Note the gap between the cubes and the end of the sticks. Create three cross braces with two popsicle sticks glued together, as shown in picture 3. Create the top frame the same way but with the recently glued cross braces as shown in picture 4, and then glue it on top.

Notice: It's essential to build the frame this way as the reinforced top frame allows for more stress to be distributed upon it, preventing any collapse from the strain that the rubber band will apply across the braces.

Use a small amount of hot glue to attach a straw to the back, as shown in picture 1.

Next, cut out the center part, as shown in picture 2.

Finally, run a dowel through the back straws and attach driving wheels as shown in picture 3.

Glue the caps together to create a single wheel, as shown in pictures 1-3.

Attach a straw to the bottom at the front of the frame, as shown in picture 4.

Finally, run a dowel through the straw and attach the frontal wheels, as shown in picture 5.

Important: Make sure to glue a cap that doesn't have a hole in it to one that has a drilled hole. Refer to images 1-3.

Synch down a zip tie on the back driving axel, then cut off any excess amount of the zip tie as shown in picture 1. This is how the rubber band will be attached to the back wheels. If the zip tie slips in the next step, apply a small amount of hot glue.
Attach a rubber band around the frame using a hitch knot on the upper frontal cross beam, as shown in picture 1.

Hook the rubber band up to the zip tie and wind it counterclockwise. Once ready, set it down and watch it fly!