STEM Activity: Balloon Racers

Have you ever wondered what makes things go? You can dive into the exciting world of motion with two helpful traits: curiosity and creativity. Explore the science of physics by building balloon racers! As you play and experiment, you’ll learn that every action has a reaction – and that science is full of fun surprises.

Materials Needed:

• Balloons
• Bamboo skewers
• Bendy straws
• Buttons
• Cardboard
• Plastic bottle caps
• Rubber bands
• Scissors
• String (optional)
• Tape
• Water bottle (empty)

Step-by-Step Instructions:

1. Create your car base by asking an adult to use sharp scissors to cut four evenly spaced holes into the water bottle where the wheels will go. Make sure the holes will be big enough for bamboo skewers to slide through.
    
2. Slide two bamboo skewers through the holes to serve as axles, then cut circular wheels out of cardboard, poke the ends of the skewers through them and secure them with tape.
   
   ** If the holes are not even or the skewers are not straight, the car will not follow a straight path; instead, it might go in circles or curve to one side. Explore different placements to see what works best.
    
3. Create an “L” shape with a bendy straw, then place the balloon over the short end of the straw and wrap a rubber band around its lip to secure it to the straw.
    
4. With the longer end toward the back of your car, attach the bendy straw to the car using tape, leaving the shorter end sticking up in the air with the balloon attached. If needed, you can use a piece of cardboard to support the short end of the straw.
    
5. Fill the balloon by blowing through the long end of the straw, then pinch the straw to keep the balloon inflated until you are ready to race. Once you release your finger, the air will begin to escape and your car will move!
    
6. Test your car and continue modifying it. Consider changing the wheels and car base to other materials.
    
7. Want a more advanced challenge? Add another straw to the side of your car’s base, then thread a long piece of string through the straw. Tie or tape each end of the string securely to two walls, keeping the string tight. This will force your car to travel in a straight path between the ends of the string when the air is released from the balloon.

What Are We Discovering?

As you observe air rushing out of the balloon and propelling your DIY car in the opposite direction, you are observing Newton’s law in action! Just like your balloon racer, all vehicles use Newton’s third law — an object in motion will stay in motion in a straight line unless acted on by an outside force.

National Inventors Hall of Fame^® Inductee Joseph-Armand Bombardier was the innovative mind behind the Ski-Doo^® snowmobile. Bombardier and his staff used a small engine and applied their own innovative designs for other mechanical components as they introduced the first rider-over-tunnel design, where the rider straddled an elongated seat and steered a pair of front-mounted skis. Behind the skis, a single wide, seamless track enabled the sled to "float" on the snow at high speed.

Bombardier liked to take apart machines, spent time understanding the transportation challenges posed by snowy terrain and even opened his own machine shop. His inventions revolutionized transportation in the snow!

Look for More STEM Inspiration

Use inspiration from Bombardier’s story and your balloon racer experiments to think of new transportation innovations! For more STEM inspiration delivered straight to your inbox, subscribe to our monthly emails filled with fun and creative ways to explore hands-on STEM.