Half-Life

When talking about radioactivity we often use the expression "half-life". The half-life is the time for one-half of the nuclei to release an alpha particle. The half-life is a constant number independent of the number of nuclei that we start with.

Half-life depends on:
· the wave function and
· the shape of the potential energy diagram

The potential energy diagram shape is directly related to the type of nucleus. Different nuclei will have different shapes.

Examples of half-lives:
237 Am Half life: 73.0 Minutes
210 Po Half life: 8.8 Days
241 AM Half life: 432.2 Years (material in smoke detectors)
226 Ra Half life: 1600 Years (material in very old glow in the dark watches)
235 U Half life: 703,800,000 Years

Take the graph you completed for the previous activity. What is the half life of this particular radioactive example? Explain your answer.