Measuring the half-life of protactinium

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, which gives students the chance to measure and analyze the decay in a single lesson.