Project #2522 on iSENSEProject.org
Radiometric Dating Lab:
• To define the terms half-life and radioactive decay
• To model the rate of radioactive decay
• To create line graphs from collected data
• To compare data
• To understand how radioactive decay is used to date archaeological artifacts
Graphing app: Desmos Go to: https://www.desmos.com
Zip Lock Bags (containing M&Ms)
Pen, Marker, Pencil
Data Collection Table
Don’t eat the M&Ms!
Each table has the radioactive element: M&Mnium.
Your task is to explain the concept of half-life of M&Mnium through radiometric dating. Each group will turn in their own individual lab report to Canvas.
• Put 50 M&M’s® candies of any color into a zip lock bag. Each group is starting with 50
M&M’s® candies, which is recorded as Trial 0 in the data table. All of the
M&M’s® candies are considered to be radioactive at the beginning.
• Shake the bag and spill out the candies onto a flat surface.
• Pick up ONLY the candies with the “m” showing – these are still radioactive. Count the
“m” candies as you return them to the bag.
• Record the number of candies you returned to the bag under the next Trial.
• Move the candies that are blank on the top to the side – these have now decayed to a
• Repeat steps 2 through 5 until all the candies have decayed or until you have
completed Trial 7.
• Record the results for 7 other groups and total all the Trials for the 400 candies.
Example Data Table:
The X-axis represents the number of half-lives. The Y-axis represents the number of radioactive M&MNiums remaining after each half-life. If you use the example data table below, you will get a steeply dipping graph. However, in order to visually see the
radioactive decay of M&Mnium on the graph, multiple each of the trials (your X values)
by 50. Please see data table 2 for an example of this with an accompanied graph.
Below is an example of what your table will look like for your trials. Your Y values will be different based on your group’s experiment.
X= Number of Half-Lives
Y= radioactive M&Mnium remaining after each trial
Example Graph and Data:
Looking above, you can see that the X values have changed, resulting in a graph that shows the half-life in a more interpretable manner. Your Y variables will be different since they are based on the class’s trials totaled.
Lab Report: Submit this to Canvas below:
What you must turn in is a short (1 page) report explaining your process, showing your graph and data table and a photo of your group performing at least one of the trialsalong with answering the following questions:
1. Why would you perform this 7 times? What would your results look like if you made
the graph after one time only?
2. If you had 10,000 M&M’s and went through 5 half lives, how many M&M’s would be "undecayed"? (You can use Desmos and make a data table/graph this if it helps!)
3. If you had 10 M&Ms left after 4 half lives, how much did you originally have?
|Name||Units||Type of Data|
Mass (amount stable)
Time (Amount decayed)
|Mass (amount stable)||Time (Amount decayed)|