Half-life and Doubling Time
Skittles or M&M’s are randomly thrown onto a paper plate. The candies that fall with a letter face up are removed. Students document throw number and number of pieces remaining. Using the exponential regression fit, we find a decreasing exponential function with a half-life of one. A similar data collection that leads to an increasing exponential function with a doubling time of one results from cutting a sheet of paper, stacking the resulting pieces and cutting again. With these definitions, the Hurricane Fran data from the Algebra 2 indicators is fit with an exponential function. Students then determine if this data has a half-life or doubling time.
Technology: M&M’s, scissors, Graphing calculator.
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