Newton's 3rd Law in Action

Balloon-Powered Art Car Challenge

Race, build, and create! Design your own balloon-powered car, decorate it with your team's style, then iterate to make it go farther and straighter.

See Build Steps ← All Activities

Hosted at Sewell Mill Library & Cultural Center

The Balloon-Powered Art Car Challenge was held on November 6th, 2025 at Sewell Mill Library. Kids built and decorated their own balloon cars, learned about motion, force, and design, competed in a friendly race, and took home their own creation — completely free!

November 6, 2025 4:00–5:00 PM 2051 Lower Roswell Rd, Marietta FREE Event

7–12

Age Range

45–60 min

Duration

2–3

Kids per Team

FREE

Always Free

The Challenge & The Science

Goal: Design, decorate, and test a balloon-powered car — then iterate to make it go farther and straighter.

The Science: When you inflate a balloon and release it, the air rushing backward creates a forward push. This is Newton's Third Law: for every action, there is an equal and opposite reaction. The escaping air is the action — your car moving forward is the reaction!

Thrust Air escaping backward pushes the car forward — jet propulsion in miniature!

Friction Wheel-to-axle friction slows the car — minimizing it makes the car go farther.

Mass Heavier cars need more thrust. Lighter cars travel farther on the same balloon puff.

Newton's 3rd Law Action = air rushing out. Reaction = car moving forward. Physics is everywhere!

Materials (per team)

1 balloon (round or long)
1 light cardboard base (index card or cut cereal box, ~8×12 cm)
4 wheels (bottle caps or cardstock circles)
2 axles (wooden skewers or coffee stirrers)
2 axle guides (drinking straws slightly wider than axles)
Tape (masking or painter's) and scissors
1 short straw (as the "exhaust" for the balloon air)
Markers and stickers for decoration
Ruler or measuring tape, floor tape for a start line

Setup (5 min)

1Mark a start line on the floor with tape.

2Clear a 3–5 meter "test track" with no obstacles.

Build Steps (20–25 min)

1Chassis: Tape two short straw pieces across the underside of the cardboard base, parallel to each other. These are your axle guides — the most important structural element!

2Axles & Wheels: Slide skewers through the straw guides. Push bottle caps or cardboard circles onto each end as wheels. Make sure the wheels spin freely — if they're tight, the car will go nowhere!

3Engine: Tape a short straw to the mouth of the balloon (seal well with tape). This straw directs the escaping air backward — that's your rocket exhaust!

4Mount: Tape the balloon on top of the chassis so the straw exhaust points straight backward off the rear of the car. Keep it level with the ground for maximum forward thrust.

5Decorate: Add your team name, colors, patterns, and a logo. Make it look awesome — this is the "Art" in STEAM! Pick a theme: race car, spaceship, jungle safari vehicle?

Test & Measure (10–15 min)

1Launch: Inflate the balloon by blowing into the straw. Pinch the straw to hold the air. Place the car behind the start line. Release the straw!

2Record: Measure the distance traveled (in cm) and how far it veered from a center line.

3Iterate: Change one variable at a time and re-test. Track your data!

Trial	Balloon (puffs)	Wheel Type	Distance (cm)	Veer (cm)
1	___	___	___	___
2	___	___	___	___
3	___	___	___	___
4	___	___	___	___

What Kids Learn (STEAM Links)

Science (Physics) Thrust, friction, mass, and Newton's 3rd Law. Forces and motion made tangible.

Technology Simple testing setup; recording and interpreting data from multiple trials.

Engineering Prototyping under constraints, iterative design, and material selection trade-offs.

Arts Branding & visual design — each car is a creative expression of the team's identity.

Math Measuring distance in cm, making bar charts, calculating average distance across trials.

Real-World Connection: Rockets & Jets!

Your balloon car is powered by the exact same principle as a rocket engine. When a rocket burns fuel, hot gas blasts out the back — the reaction pushes the rocket forward. Even the International Space Station uses small thruster rockets that work this way to adjust its orbit. Newton's Third Law is one of the most important physics principles in the universe!

Fun Fact: The fastest land vehicle ever built, the ThrustSSC, broke the sound barrier at 763 mph — powered by two jet engines using this same action-reaction principle. Your balloon car is the world's most adorable version!

Safety & Tips

Use blunt-tipped skewers or trim sharp points before distributing to kids.
Supervise scissors use at all times.
Remind kids not to overinflate balloons — they can pop!
Ensure wheels spin freely before testing — if they don't, widen the straw guides slightly.
Keep the test track clear before each launch so no one gets hit by a speeding car!

Extensions & Bonus Challenges

Ramp Test: How does a gentle starting slope change your results?
Payload: Add a paper clip "cargo" to the car and re-test. Does extra weight help or hurt?
Art Theme Race: Space cars vs. ocean cars vs. jungle cars — award design points on top of distance!
Graphing: Plot distance (y-axis) vs. number of balloon puffs (x-axis) to find the sweet spot.
Straightness Challenge: Place two tape lines on the floor. The car must stay between them. Who can build the straightest-running car?

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