Radioactive half life ... popcorn ... Count out 12 (can halve and quarter it) corn kernels and heat them in a beaker. Get kids to count and time for half of them to pop! Usual half life for popcorn = 3 to 4 mins. Hot beaker works best and don't use too strong a flame without keeping it moving otherwise they burn ... don't be tempted to use too many ... can take ages and char rather than explode. Best effect if a few leap out of the beaker ...

Radioactive half life ... popcorn ... Count out 12 (can halve and quarter it) corn kernels and heat them in a beaker. Get kids to count and time for half of them to pop! Usual half life for popcorn = 3 to 4 mins. Hot beaker works best and don't use too strong a flame without keeping it moving otherwise they burn ... don't be tempted to use too many ... can take ages and char rather than explode. Best effect if a few leap out of the beaker ... Graph of no. of corn kernels against time. First half life only - have to imagine times for 3 corns onwards as popcorn does not decay exponentially - then to choose number for third time (lots choose 1.5!!!)to show decay curve. Good for discussion about how useful model is ... visible, random etc.