Balloon Powered Car Instructions
You can make a balloon-powered car using a few items that you may already have around the house. Be creative and make a lightweight, stylish racer. Then challenge your friends to build a customized car of their own and set up a balloon-car raceway.
Four matching pieces of almost anything lightweight and round will work as wheels for your balloon-powered car. You could use ping pong balls, plastic cup bottoms, toys wheels, empty spools of thread or even old compact discs that you no longer listen to. For the axles, use two identical, lightweight, rigid items such as rounded chop sticks or straightened paper clips. Slide three 2-inch cut pieces of plastic drinking straw onto the middle of each axle and hold them loosely to assure that the axles will spin smoothly inside. Connect each pair of wheels to the axles. Test roll each set of wheels to ensure that they roll straight, making any needed alignment adjustments.
A balloon with a well-directed exhaust nozzle will give your car the power to move. Use a high-quality round balloon rated for use with helium. These thicker balloons last longer and inflate to many times their original size, so they hold more air than novelty balloons. Blow up a balloon and deflate it a few times. This will stretch it out and make it easier to blow up once the nozzle is attached. Insert a 3-inch cut length of plastic drinking straw halfway into the balloon and tape it securely to form an airtight seal. Test the seal by blowing up the balloon again and covering the open end of the straw with a finger while listening for air leaks.
Find a body for your balloon-powered car that is lightweight and will fit over the inflated balloon. A large clear-plastic top from a carry-out salad will work. Use hot or super glue to attach the three straw segments on the axles to the closed side of the lid. Be careful not to get any glue inside the straw and onto the axle. When the glue has dried, use tape to secure the nozzle of your balloon to the open side of the lid, so that the nozzle points out from the back of the car. Test the car by blowing up the balloon and releasing the car on a flat surface. Adjust and re-tape the nozzle if the vehicle isn't going straight.