2. Background The half-life of a radioactive element is the time it takes for half of its atoms to decay into a stable isotope or element. Radiometric dating is used to determine the absolute age of fossil and rocks layers in the geologic column. You will be determining the half life of a radioactive material (m&ms, skittles, etc)

3. Your Write-up Develop a hypothesis demonstrating the relationship between the number of tosses for your radioactive material. If the rate of decay is related to number of “tosses” then an increased number of tosses will result in a decrease rate of decay.

4. Data Table TossTrial 1 # un- decayed Trial 2 # un- decayed Trial 3 # un- decayed Total Un-decayed Average 0 1 2 3 4 5 6 7 8 9 10

5. Analysis Using the graph paper provided, construct a graph of N (number of undecayed atoms) as a function of the number of tosses. Use the average of the three trials to construct this graph. (Remember to label your x-axis, y-axis, and title) Calculate the half-life of your radioactive material.

6. Conclusion Calculate the half-life of your radioactive material. –On the y-axis find 50; draw a dotted line horizontal to the x-axis starting at 50 and stopping when it reaches the curve. Now starting at this point on the curve, draw a dotted line parallel to the y-axis stopping at the x-axis. Does this match the number of tosses it took? Explain. How many tosses were needed to use up half of the 50 atoms? What does this tell you about the half-life of your radioactive material? What would the half-life be if you used 2000 “atoms?” Explain you answer.