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Bike Shop 3-5 / Week 06 / Thursday
4/6
Week 06 · Patterns of Motion

Thursday

Big wheels, small wheels
// Measure, find the pattern, predict
⏱ about 15 min

Thursday: Big Wheels, Small Wheels

Rocket lines up a tiny toy car wheel and a big wagon wheel.

"They both turn once," he says. "So they go the same distance, right?"

Raven tilts her head. "What do you notice about how big around each one is?"

Nova hovers between the wheels. "Wrap a string around each," she says. "Compare the strings."

Bigger around, farther along

A bigger wheel has a bigger distance around it.

So a bigger wheel rolls farther in one turn.

Old high-wheel bikes used this idea.

The bigger the front wheel, the farther the rider went with each pedal turn.

One museum scientist said a rider might go 140 inches in one pedal turn!

Made-up wheelDistance aroundOne turn rolls
toy car wheel5 cm5 cm
wagon wheel50 cm50 cm
WHICH GOES FARTHER?
  • Read the question.
  • Tap your answer.
Which made-up wheel rolls farther in one turn?
Was Rocket right that both wheels go the same distance?
On a high-wheel bike, what did a bigger front wheel do?
Made-up wagon wheel: 50 cm per turn. 2 turns go how many cm?
Made-up toy wheel: 5 cm per turn. How many turns to go 20 cm?
StatementTrue or false?
A bigger wheel rolls farther in one turn.?
All wheels roll the same distance in one turn.?
A wheel rolls about its distance around in one turn.?
WHY THIS EXERCISEEach turn rolls one circumference, and bigger wheels have bigger circumferences.
Try it
Find two round things of different sizes, like a can and a cup.
Wrap a string around each one and compare.
Predict which rolls farther in one turn. Then test it.
Safety first
Use round things that will not break, like plastic cups.
Roll them gently on the floor in a clear space.
No bike needed today.
Round thingString length (mine)One turn rolled (mine)
smaller one
bigger one
In your shop notebook, sketch your two round things. Show which one rolled farther.

Big thinking about wheels! Tomorrow we find out why rolling things slow down.

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