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Builder's Lab / Week 09 / Thursday
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Week 09 · Balloon Car

Thursday

Why did it stop?
// A car pushed by balloon air
⏱ about 20 min

Thursday: Why Did It Stop?

Rocket's car shudders forward and stops.

"Ten inches," Nova reports.

Rocket blinks, then grins. "We can improve it!"

Raven lies down to look under the car. "What do you notice?"

"The wheels rub on the cardboard," Rocket says. "They barely turn!"

VersionProblemHow far (inches)Past 3 feet?
Rocket version 1Wheels rub the cardboard10No

Compare possible fixes

The crew thinks of three fixes. Which one fits the problem?

FixIdea
Fix ASlide the wheels out so they do not touch the cardboard
Fix BPaint the car a new color
Fix CUse a much bigger balloon
PICK THE BEST FIX
  • Read the question.
  • Tap your answer.
Which fix solves the rubbing problem?
Why is Fix C not fair?
READ THE TABLE
  • Read the question.
  • Tap your answer.
How far did version 1 go?
Draw your car with wheels that spin freely.

Match the fix to the problem

A good fix solves the real problem.

The problem was rubbing wheels.

Paint does not stop rubbing.

A bigger balloon breaks a rule.

Free wheels stop the rubbing.

FIX DETECTIVE
  • Read the question.
  • Tap your answer.
What was the real problem?
Why will Fix B not help?
How did Raven find the problem?
IdeaTrue or false?
Rocket was upset his car stopped.?
Engineers compare fixes before they build.?
A fix should match the problem.?
WHY THIS EXERCISEComparing fixes saves time and materials.
Try it
Lie down and look under your car.
Spin each wheel.
Find any spot where a wheel rubs.
Safety first
Keep stick ends away from eyes.

You compared ideas and picked the best one!

Tomorrow, we test version 2.

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