This experiment is designed to help you understand the concept of half-life. You will need the following materials to complete this activity: 32 nickels 32 pennies Red and blue colored pencils Step 1: Place the 32 nickels heads-side up on the lab table. These represent atoms of the radioac- tive parent isotope. Step 2: Place the nickels into a container, shake well, and dump them onto the lab table. Step 3: Count and remove all the nickels that are tails-side up. The nickels you remove repre- sent parent atoms that have decayed. Re- place each tails-side-up nickel with a penny. The pennies represent daughter atoms. Step 4: On the chart in FIGURE 9.18, record the num- ber of remaining nickels (heads-side up) and the pennies that represent the daughter atoms. The combined total should equal 32 coins. Step 5: Place these coins in the container and repeat steps 3 and 4 until only one or two nickels remain. After you have completed the exercise (Trial 1), use a blue pencil to plot the number of nickels that remained at each interval and connect the points with a solid line on the graph (FIGURE 9.19). This line rep- resents the change in parent atoms over time. Next, use a red pencil to plot the number of pennies at each interval on the same graph and connect the points with a solid line. This line represents the change in the number of daughter atoms over time. Repeat this experiment (Trial 2), using the table in FIGURE 9.20 and the graph in FIGURE 9.21. 1. Compare the graphs you completed with the ideali- zed half-life graph shown in FIGURE 9.22. What dif- ferences do you observe? 0 1 2 3 4 5 6 TRIAL 1 Number of Nickels 32 Number of Pennies 0 FIGURE 9.18 Chart to record data from Trial 1. NUMBER Nickels Pennies 35 30 25 20 15 10 TRIAL 1 3 5 6 Time FIGURE 9.19 Graph to plot data from Trial 1.