M&Mium Radioactive Decay & Background Radioactive isotopes emit particles and energy in an effort to become stable. For some elements, this takes a long time and in other cases it happens very quickly.
? Question
Half-Lives
Do all half-life graphs look similar?
Radioactivity
Materials Licorice and M&Mium Decay Graph 100 M&M’s® in a cup Paper towel
Procedure 1. Create a data table in your science notebook (like the one to the right) with Half-Lives as the independent variable and Radioactivity as the dependent variable. 2. Count out 100 “radioactive” M&M’s®. (Discard any yellow M&M’s® as they are too difficult to read! Make sure you replace them with a different color.) 3. In your data table, enter 0 for “Half-Lives” and under “Radioactivity” enter the TOTAL number of “radioactive” M&M’s® you are starting with—100. 4. Put the “radioactive” candies in a container (cup or bag), shake them up and then carefully dump them onto the paper towel. 5. Remove all the M&M’s® that are face down (with the M not showing)—these have “decayed” and become stable in the simulation. 6. Enter 1 for half-lives and record the number of remaining “radioactive” candies in your data table. 7. Place the candies that remained “radioactive” back into the cup, shake lightly and repeat this process until all the “radioactive” candies have become stable. Be sure to increase the number of half-lives by one for each shake. 8. On the same graph you used in Licorice Decay, place the number 100 at the same height along the vertical y-axis as you placed the mark above the full length licorice for 0 half cuts. 9. Appropriately scale the rest of the vertical axis based on the origin being 0 and the mark you just made being the total number of “radioactive” M&M’s® you started with at 0 half-lives—100. Graph the rest of your data from the candy trials.
Analysis 1. Compare your graph to a neighbor’s. What similarities and differences do you see?
Conclusion 1. As you look at your graph and your neighbor’s, what do you notice? How is this activity similar to what happens in the natural world?
2. How does the graph for the licorice compare to the graph for the M&M’s® decaying?
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Energy From Uranium
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