The following is a simple activity that will help you visualize exponential decay. You will need 50 small candies that have letters on one side of them (like M&M’s® or Skittles®) and a plastic zipper seal bag. You will also need to access the whiteboard. The whiteboard contains a data table, an empty graph, and a Notes section for you to enter information.
1. Place the 50 candies in the bag and seal it. Shake the bag for 10 seconds, and then open it and pour the candies outon a table. Remove all the candies that have the letters on them facing upward and leave the ones that have the letters facing downward. Eat the ones you removed, and count how many are left remaining on the table. Record this number in your data table in the whiteboard. Then calculate the percentage of candies remaining using the following formula:
2. Now place the remaining candies back in the bag and seal and shake again for 10 seconds. Then do just as before and remove and eat all of the candies that have the letters facing upward but leave and count the ones that have the letters facing downward.
3. Repeat this process with your remaining candies until you have only two or three left, each time shaking the bag for 10 seconds and each time recording your data in the data table.
4. Graph the information from your data table on the blank graph. Graph the data for time on the x axis and the data for the % of the original candies remaining on the y axis. Remember to determine an appropriate scale for the y axis before you enter your data.
5. In the notes section of the whiteboard, explain how this activity demonstrates exponential decay. If this were radioactive decay, approximately what would be the half-life of your candy?
6. Save your whiteboard and submit it to the Assignment: M&M’s® Decay assignment link for grading. For more information on how this assignment will be graded, review the Assignment: M&M’s® Decay Rubric