1. 22.2 Radioactive decay Analogue of radioactive decay 1.Start with 100 dice, each one representing an unstable nucleus. 2.Throw the dice onto a tray. 3.Dice that come up with a ‘6’ represent decayed nuclei and are removed. Supplementary materials

2. 22.2 Radioactive decay 4.Write down the number of ‘undecayed nuclei’ after the throw. 5.Repeat by throwing the remaining dice until only a few dice remain. Number of throws Number of dice remaining 0100 184 268 354 446 540 634 730

3. 22.2 Radioactive decay 6.A ‘decay’ curve’ is plotted as shown. 12345671234567 number of throws 0 100 80 60 40 20 number of dice remaining

4. 22.2 Radioactive decay There are some similarities between this dice and radioactive decay. Dice game Radioactive decay impossible to predict when a particular dice will ‘decay’ impossible to predict when a particular nucleus will decay 1.

5. 22.2 Radioactive decay Dice game Radioactive decay 2.The number of dice ‘decayed’ in each round is proportional to the number of ‘undecayed’ dice. The number of unstable nuclei that decay in a given time is proportional to the number of undecayed nuclei.

6. 22.2 Radioactive decay Dice game Radioactive decay 3.For every 3 to 4 rounds, the number of ‘undecayed’ dice is reduced by half. For each fixed period of time, the number of undecayed nuclei is reduced by half.