1. 7.1.4 What if it does not grow? Exponential Decay

2. Standards A ‑ CED.1. Create equations in one variable and use them to solve problems. F ‑ IF.8b. Use the properties of exponents to interpret expressions for exponential functions. For example, identify percent rate of change in functions such as y = (1.02) t, y = (0.97) t, y = (1.01) 12t, y = (1.2) t/10, and classify them as representing exponential growth or decay. F ‑ IF.7e. Graph exponential functions, showing intercepts and end behavior.

3. More Standards F ‑ LE.1c. Recognize situations in which a quantity grows or decays by a constant percent rate per unit interval relative to another. F ‑ LE.2. Construct exponential functions given a graph, a description of a relation ‑ ship, or two input ‑ output pairs (include reading these from a table). F ‑ LE.5. Interpret the parameters in a linear or exponential function in terms of a context.

4. The M & M Lab Start with a cup full of M & Ms. Trial #1: Dump the M & Ms out on your team’s workspace. Remove any candies that are “M” down. Record the number of candies that remain in a table as shown on a slide that follows. Trial #2: Gather the candies that show an “M”. Put these candies back in the cup, shake them up, and dump them on your workspace again. Remove any candies that are “M” down and count the number of candies that remain. Record the number in your table. Trial #x: Continue this process until the last candy is removed. Record all results in your table.

5. The M & M Lab cont. Make a scatterplot of the data collected in your table. Once perfected, graph your team results on the class graph on the smart board.

6. Questions Prior to Lab What does trial #0 represent? Is it possible that a team conducting this experiment might never remove their last candy? Explain.

7. The M & M Lab Data Trial Number (x)Number of Candies Remaining (y) 0 1 2 3 4

8. Questions After Lab

9. Exit Ticket Mrs. Pierce’s sons built a 100 pound snowman. In the warm weather, half of the snowman melts away every day. Write an equation that models the weight of the snowman (y) after x days.