Analyze
1. What happens to the number of unstable pennies as the number of half-lives increases?










2. Approximately what percentage of pennies were removed after each half-life? Why do you think this was the case?















3. What does the shaking of the pennies represent? Would the amount of time spent shaking the pennies affect your data?















4. What happens to the number of unstable thumbtacks as time passes?










5. Compare the shapes of the two graphs. What are the similarities? What are the differences? Describe the shape of each graph.




















Draw Conclusions

1. Imagine that you repeat experiment 1 with a sample of 500 pennies. About how many pennies would still be unstable after 3 half-lives?




















2. Does the number of shakes in experiment 2 represent the number of half-lives that have passed? Why or why not?















3. Let each shake of the pennies or thumbtacks represent 1 year. What is the half-life, in years, for the pennies in experiment 1? What is the half-life, in years, for the thumbtacks in experiment 2?




















Explore Further
Develop models to illustrate the changes in the composition of the nucleus of the atom and the energy released during the processes of fission, fusion, and radioactive decay. Your models can be physical or mathematical.