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Week 09 · Balloon Car

Monday

The balloon car challenge
// A car pushed by balloon air
⏱ about 20 min

Monday: The Balloon Car Challenge

A grown-up blows up a balloon and lets it go.

It zooms around the lab and flops down.

Rocket laughs. "What if that push moved a car?"

Raven points to the floor. "Let's say three feet. Can it go that far?"

Nova scans the balloon. "Interesting. Would you like a hint? Wheels need to spin."

The challenge

  • Goal: a car that rolls at least 3 feet on balloon air.
  • Nobody pushes the car.
  • Use one balloon, blown up to the same size every test.
  • Build the car from cardboard, straws, bottle caps and sticks.

Many solutions

There is more than one way to build a balloon car.

Engineers think of many solutions first.

Then they pick the one most likely to meet the goal.

THE CHALLENGE
  • Read the question.
  • Tap your answer.
The car rolls 4 feet with no push. Did it meet the goal?
The car rolls 5 feet, but Rocket gave it a shove. Did it meet the goal?
FAIR BALLOONS
  • Read the question.
  • Tap your answer.
Why blow the balloon to the same size each time?
Draw two different car ideas.

Feet and inches

One foot is 12 inches.

Three feet is 36 inches.

A ruler is often 12 inches long.

So three rulers end to end make 3 feet.

CAR RULES
  • Read the question.
  • Tap your answer.
How many rulers end to end make 3 feet?
What pushes the car?
The car rolls 2 feet. Did it meet the goal?
RuleAllowed?
Build with cardboard, straws and bottle caps.?
Give the car a little push.?
Use one balloon, the same size each time.?
Blow the balloon bigger for the second test.?
WHY THIS EXERCISESame rules for every car make the rally fair.
Try it
Lay three rulers end to end on the floor.
That is 3 feet.
A grown-up can mark the end with tape.
Safety first
Keep the floor clear so nobody trips.

Many ideas make better builds!

Tomorrow, we learn how balloon air pushes.