How To Make A Balloon Powered Car

Kids love building things that move! Plus, it’s even more fun if you can make a car go without pushing it or by adding a motor. Instead, find out how to make this fun balloon powered car and test out how far you can make it travel. A balloon car is an awesome physics and engineering activity for your next STEM project.

Balloon Car Science Fair Project

In the balloon-powered car experiment, students can apply the engineering design process by brainstorming different designs, building a prototype, and testing how well it moves. By adjusting the wheels’ size, the car’s shape, or how the balloon is attached, students can redesign and improve their car’s performance, learning how different designs affect speed, distance, and stability.

💡 A balloon-powered car is a great science fair project for elementary students! It demonstrates important physics concepts like force, motion, and energy.

Students can set up variables for a successful science fair project to test how different factors affect the car’s performance. Here’s how they can structure it:

Independent Variable: This is what the student changes. For example, the size of the balloon, the type of wheels, or the surface the car moves on.

Dependent Variable: This is what the student measures. They can measure how far the car travels or how fast it goes.

Controlled Variables: These are the things that stay the same, such as the weight of the car, the design of the car, and the angle of the release point.

By changing one variable at a time (like balloon size) and keeping everything else the same, students can see how it affects the car’s speed or distance, making it an age-appropriate way to explore cause and effect.

Recommended Grade Level: 3-5th Grade

Supplies:

Grab free printable instructions below! What different materials can you use to make a balloon-powered car? How about a cardboard box or plastic bottles?

• Balloon
• Lollipop sticks
• Toilet paper tube
• Hole puncher
• Hot glue gun
• Tape
• Straws or Wooden skewers
• Scissors
• 4 Plastic bottle caps

How to Make a Balloon Car

💡 Similar to how a balloon car works, try this awesome balloon rocket!

STEP 1: Cut off two lollipop sticks and hot glue the sticks to two bottle tops. Alternatively, you can make holes in the plastic bottle caps and insert wooden skewers to make axles.

STEP 2: Use the hole puncher to punch four holes in the toilet paper tube to attach the wheels.

STEP 3: Stick the lollipop sticks through the holes, and then glue on the remaining two tops/wheels.

STEP 4: Punch another hole in the top of the tube near the front of the car and stick a straw through the hole.

STEP 5: Tape the end of the balloon to the straw.

STEP 6: Now blow through the straw to inflate the balloon.

Set down the car while holding the straw closed, then let go and watch the fun! How far can your car go?

The Science Behind a Balloon-Powered Car

When you build a balloon-powered car, you’re seeing science in action! Let’s break down how it works using some important science concepts.

Potential Energy and Kinetic Energy

When you blow up a balloon, you add potential energy to it. This energy is stored in the stretched balloon. When you release the balloon, the compressed air inside rushes out. This changes the potential energy into kinetic energy, the energy of motion. The car moves forward because of this change from stored energy to motion.

💡Learn more about Potential and Kinetic Energy [here].

Newton’s Laws of Motion

This experiment also shows Newton’s Laws of Motion. The first law says an object will stay still or keep moving in a straight line unless an outside force acts. In this case, the car stays still until the air rushes out of the balloon.

Now, let’s talk about Newton’s Second Law: It tells us that the more force you apply to an object, the faster it will go (this is called acceleration). The air escaping from the balloon pushes against the car, making it move forward. The amount of air in the balloon affects how fast the car accelerates. More air means more force, so the car moves faster!

💡Explore more with force and motion [here].

Reaction Force

The balloon also demonstrates something called a reaction force. As the air pushes backward out of the balloon, the car is pushed forward in the opposite direction. This is an example of Newton’s Third Law, which says that for every action, there’s an equal and opposite reaction.

Friction

However, the car doesn’t keep moving forever. Friction is the force between the car’s wheels and its rolling surface. Friction slows the car down, and eventually, it stops. If you try different surfaces, you’ll see that the amount of friction changes how far your car goes. Smoother surfaces have less friction, so the car goes farther, while rough surfaces have more friction, which slows it down more quickly.

More Fun Things To Build

You can also use wind energy to power a car!

• Make a rubber band car.
• Build a wind powered car.
• Construct a cardboard marble run.
• Build the best popsicle stick catapult.
• A marble roller coaster is fun to make.
• Build a simple robot car.
• Make a water clock.

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Printable STEM Activities Pack for Kids