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Balloon-Powered Car Grand Prix

Students design and build a LEGO car powered entirely by air escaping from a balloon. After creating a working prototype, they race their cars, observe what affects speed and distance, and redesign their vehicles to improve performance.

Primary

Kinetic/Potential energy; propulsion

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Project Details

Theme

November | Physics

Messy Level

1

Suggested Location

Class or lab

Prep & Classroom Structure

Prep

  • Sort LEGO pieces into several containers.

  • Create a separate container specifically for wheels and axles.

  • Mark a starting line on the floor with masking tape.

  • Create a testing lane approximately 10–15 feet long.

  • Build one sample LEGO balloon car, but avoid showing students an overly polished design so they are encouraged to engineer their own.

  • Place measuring tapes alongside the racing area if students will record distance.


An alternative to legos would be using cardboard and axels. Let me know if you'd like to try the alternative for more of a challenge.


Instructions for lego cars: https://frugalfun4boys.com/lego-fun-friday-balloon-powered-car-building-challenge/

Materials

  • Assorted LEGO bricks

  • 1 LEGO base plate or long LEGO plate

  • 4 LEGO wheels

  • 2 wheel axles or LEGO wheel assemblies

  • 1 latex balloon

  • LEGO pieces that can create a holder/opening for the balloon

  • Measuring tape or yardstick

  • Optional masking tape for marking the starting line

Project Instructions

1. Build the chassis

Create the base of your vehicle using LEGO plates or bricks.


2. Add the wheels

Attach four wheels so that they spin freely.


Test the vehicle by gently rolling it.


If the wheels drag against LEGO pieces, redesign the chassis.


3. Create a balloon holder

Build an opening toward the rear of the car where the neck of the balloon can rest.


The balloon should point backward.


The original project used specialty LEGO pieces such as an arch or bar piece, but basic LEGO bricks can also be arranged to create a gap that holds the balloon.


4. Attach the balloon

Slide the neck of the balloon through the LEGO opening.


Make sure the inflated balloon will not rub against the wheels.


5. Inflate the balloon

Hold the car and carefully inflate the balloon.


Pinch the balloon opening closed.


6. Position the car

Place the car behind the starting line.


Make sure all four wheels are touching the ground.


7. Launch!

Release the balloon opening.


Do not push the vehicle.


Watch the car race forward.


8. Measure

Measure how far the car traveled from the starting line.


Record the result.


9. Redesign

Change one feature of your car.


10. Race again

Test the redesigned vehicle.


Compare your results.

Class Video



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