Exercise 1 Simulating Half-lives In this exercise, you will simulate radioactive decay by studying the outcome of coin tosses. Procedure Each coin toss that lands heads-up will represent an atom that does not decay, whereas a coin that lands tails-up will represent decay to the daughter atom. You will start with 50 coins representing a sample of 50 parent isotopes. 1 Calculate the predicted number of parent isotopes you will have after each half-life if you were to start with a sample containing 50 parent atoms. Record the predictions in Data Table 1. Note: Remember the half-life is the time it takes for half of the parent isotope to decay to its daughter isotopes. 2 Gather 50 pennies and follow these instructions for Trial 1: a Toss each penny once and record the total number of pennies that land heads-up in Data Table 1. The heads-up pennies represent the remaining parent isotopes that did not decay. Move the tails-up pennies to the side; these represent the daughter isotopes that underwent decay. b Collect the pennies that landed heads-up and toss each penny once. Record the number of pennies that land heads-up in Data Table 1. Repeat this process until all remaining coins land tails-up. Note: Completely fill out the data table. Any remaining trials that were not conducted should be recorded as "0" in the data table. For example, if it only takes 6 trials to reach all tails-up coin tosses, record a "0" for trials 7 - 10. 3 Repeat step 2 two more times, and record the results for Trial 2 and 3 in Data Table 1. 4 Graph the data in Data Table 1 of the half-lives for predicted number of parents and also actual parents in Trials 1, 2, and 3. Plot the number of parent isotopes on the dependent, vertical axis (y-axis) and plot the number of half-lives on the independent, horizontal axis (x-axis). Add an exponential trendline to the predicted number of parents. Note: If you do not have access to graphing software, download and print the Graph Paper Template to create the graph and draw an estimated trendline. 5 Take aphoto of the completed graph and upload the image into Graph 1. Exercise 1 - Questions Question 1 How did the predicted values compare to the actual values in Data Table 1 and Graph 1? Explain sources of variability in the outcomes of this experiment. B I U = i= Tic T 0 Word(s) Question 2 What would Graph 1 look like if only 5 pennies were used in this experiment? What if 10,000 pennies were used? Based on your responses, what might be inferred about the relationship of half-life and sample size? B | u = = T T, 0 Word(s) Experiment 1 Data Table 1 Number Predicted # of Parents Graph 1 of Half- Exercise 1 lives Trial 1 Actual # of Parents 50 Trial 2 1 50 25 Trial 3 50 25 2 50 13 21 24 3 11 6 13 6 14 4 3 6 6 5 4 2 2 6 2 1 7 1 0 0 0 8 0 O 0 0 0 0 0 0 0 0 0