Probability Spinner Lab

The chance of landing on a part of a spinner is simply how much of the circle that part takes up. What a short run of spins gives you is something else: results are lumpy, and six heads in a row is perfectly ordinary. Spinning hundreds of times shows the two coming together — the results settle towards the shares, and they do it whether the spinner is fair or not. Students can change how many parts and make part a bigger and compare what happens. Use it for math inquiry with Grades 3–5 and Middle School on a projector or student device.

Standards: Common Core CCSS.MATH.CONTENT.7.SP.C.6, CCSS.MATH.CONTENT.7.SP.C.7

• Spin ten times and see how far the results can be from the prediction
• Spin several hundred and watch the gap between the two sets of bars shrink
• Make one part bigger and check that the results settle on the new, unfair shares
• Switch to a coin or a die and see the same thing happen with different outcomes
• Clear the tally and run it again — the wobble is different every time, the destination is not

1. 1Predict how changing how many parts will affect the chance of a, then test the prediction.
2. 2Use evidence from the interactive visual to explain the result.

Questions teachers ask