Atoms and nuclei > radioactive decay

Measuring the half-life of a radioactive isotope brings some of the wonder of radioactive decay into the school laboratory. Students can witness one element turning into another and hear (or see) the decrease in the radiation it gives out as it transmutes. 
 
This demonstration uses a 'protactinium generator' to show the exponential decay of protactinium-234, a grand-daughter of uranium. It has a half-life of just over a minute,

In this activity, students model radioactive decay using coins and dice. By relating the results from the model to the experimental results in Measuring the half-life of protactinium, students can see that the model helps to explain the way in which a radioactive substance decays. The model provides an insight into what might be happening within radioactive atoms. 
 
This activity is a good analogy of radioactive