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Bike Shop 3-5 / Week 06 / Tuesday
2/6
Week 06 · Patterns of Motion

Tuesday

One turn, one trip around
// Measure, find the pattern, predict
⏱ about 15 min

Tuesday: One Turn, One Trip Around

Rocket rolls a can across the floor. "I bet one turn goes one hand long," he says.

He tries it. It goes much farther!

Raven wraps a string around the can. "What do you notice if we lay this string flat?"

Nova hovers beside the string. "Put the can next to it," she says. "Then roll it once."

The distance around

The distance all the way around a circle is its circumference.

When a wheel rolls one full turn, it moves forward one circumference.

So a wheel rolls as far as the distance around itself in each turn.

  1. Find a can or a round jar.
  2. Wrap a string once around its middle.
  3. Mark where the string meets its end.
  4. Lay the string flat on the floor.
  5. Put a dot of tape on the can, touching the floor at the string's start.
  6. Roll the can one full turn, until the dot touches the floor again.
  7. Compare where the can stopped to the string's mark.
Safety first
Use a can with no sharp edges, or a plastic jar.
A grown-up checks the can first.
Roll on the floor in a clear space.
Using a bike wheel? A grown-up holds the bike and rolls it slowly.
What I measuredMy result
Length of string around the can
Distance the can rolled in one turn

Practice with made-up numbers

These are made-up practice numbers, not your can.

Made-up wheelDistance around it
small can20 cm
toy wheel15 cm
big jar30 cm
The small can rolls one turn. How many cm?
The toy wheel rolls one turn. How many cm?
The big jar rolls one turn. How many cm?
AROUND AND ALONG
  • Read the question.
  • Tap your answer.
What is the circumference of a wheel?
A wheel rolls one turn. How far does it go?
What is the word for the distance around a circle?
WHY THIS EXERCISECircumference is the distance all the way around a circle.

Brilliant measuring! Tomorrow we use this pattern to predict many turns.

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