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Bike Shop 3-5 / Week 06 / Bike Shop Day
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Week 06 · Patterns of Motion

Bike Shop Day

Bike Shop Day: Roll and Predict
// Measure, find the pattern, predict
⏱ about 15 min

Bike Shop Day: Roll and Predict

Rocket lays a long strip of tape on the driveway. "Today we predict before we roll!"

Raven opens the shop notebook to a fresh page.

"What do you notice about the wheel?" she asks. "Where should we mark it?"

Nova hovers above the tape. "Mark the wheel where it touches the ground," she says. "Then count turns."

  1. Some motion follows a pattern, and patterns help us predict.
  2. One wheel turn rolls one circumference, the distance around the wheel.
  3. More turns go farther: multiply the distance per turn by the turns.
  4. Bigger wheels roll farther in one turn.
  5. Rolling resistance slows rolling things. Rough and soft surfaces slow them more.
◇ ROLL AND PREDICT
Choose a wheel: a bike wheel with a grown-up, or a can or round jar.
Put a small piece of tape on the wheel where it touches the ground.
Mark a start line on the ground under the tape.
Roll the wheel slowly, one full turn, until the tape touches the ground again.
Measure from the start line. That is one turn.
Predict how far three turns will go. Write it down.
Roll three turns from the start line, then measure.
Compare your prediction to your measurement.
Safety first
A grown-up walks the bike slowly. Nobody rides it for this test.
Keep hands away from the spokes, chain and gears while the wheel turns.
Do the test where a grown-up says, away from cars.
No bike? Use a can or a round jar on the floor.
For a grown-up
Walk the bike slowly in a straight line while your child watches the tape mark.
Let your child measure and record. Help read the tape measure if needed.
Ask: why might three turns not be exactly three times one turn?
What we foundOur number
One turn rolled
Prediction for three turns
Three turns measured
SHOP DAY CHECK
  • Read the question.
  • Tap your answer.
Where should the tape mark go?
A made-up wheel rolls 150 cm in one turn. How far in three turns?

Great family science! Next week we squeeze the brakes and learn how friction stops a wheel.

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