Play with the wheel

Compare a small wheel and a large one. The contour corresponds to a little more than three diameters in both.

Explore the controls and explain what changed in your own words.

Your mission: investigate the shapes

Start by measure and find out. Use paper, string and a ruler. On this trail, we explore concrete situations: the definition of irrational and the demonstrations are for the next steps.

Measurement challenge

Two people measured the same object and wrote down 8,1 cm and 8,2 cm. Do we need to conclude that one of them was wrong?

Check out the discovery

Not necessarily. Ruler positioning and reading accuracy may produce small differences. We can repeat the measurement and explain how it was done.

To move forward: record a measurement with its unit and explain why it can be approximated.