Here, time is represented by trials. Students should record these numbers and continue finding the number of trials it takes to remove half the atoms, until all have decayed. Students should average the numbers of trials determined in step 3. Half-lives of actual isotopes are constant lengths of time. In this model, the number of trials per half-life might vary.
Students can graph their data to illustrate their isotope's rate of decay.
Compare and discuss graphs for different isotopes. Have students fill the box with the appropriate number of radioactive atoms and stable daughter atoms to represent the age of their rock. Have groups exchange boxes and half-life information. Ask each team to calculate the age by comparing the ratio of the original radioactive atoms to daughter atoms. For results for this activity, click here.