Three-sided Coin Activity

Help us estimate the dimensions of a fair cylindrical three-sided coin, by taking part in our experiment!
Age groups relevant for by Key Stage:
KS3,
KS4,
KS5
Possible duration of tasks:
30 mins - 1 hour,
1 hour – 2 hours

Equipment needed

Coins of different thicknesses - see teacher notes for details of how you can obtain/make these

Curriculum Topics Covered

Experimental probability and data collection; geometry and trigonometry; manipulating equations

Help us estimate the dimensions of a fair cylindrical three-sided coin, by taking part in our experiment!

We are trying to find the ratio between the diameter and thickness of a cylindrical coin that when thrown would give a one third chance of the coin landing on its edge, as opposed to one of its faces. We are asking people to help us find out! Get some sets of cylindrical coins of different diameter/thickness ratios, and have your class conduct an experiment to estimate how likely each type of coin is to fall on its edge. Then give us your results! This experiment is inspired by a video on the Stand-Up Maths YouTube channel (link below).

We also have created a set of worksheets to accompany the experiment, that lead the students through Hugh and Matt's possible theoretical solutions, and show them how to calculate if their results to this experiment are statistically significant.

Read our teacher notes to find out how to get your own coins, what you'll need to do the experiment and notes about the additional worksheets.

Some useful links

Form to submit your results: bit.ly/coinsubmit

Form to request to borrow Hugh's set of coins: bit.ly/coinrequest

3D printing files to print your own coins: bit.ly/3Dcoinfiles

Shapeways listing to buy 3D printed coins: bit.ly/3Dcoinshop

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