Concept half life used radiometric dating
Once students are in their groups, with supplies, and general directions are given, they are on their own for doing their runs.
Students will record the number of M&Ms that are still "radioactive" (M side up) in their data table after each run, and set aside the "stable" (M side down) M&Ms.
These artifacts have gone through many carbon-14 half-lives, and the amount of carbon-14 remaining in them is miniscule and very difficult to detect.
Carbon dating cannot be used on most fossils, not only because they are almost always allegedly too old, but also because they rarely contain the original carbon of the organism that has been fossilized.
The age of the carbon in the rock is different from that of the carbon in the air and makes carbon dating data for those organisms inaccurate under the assumptions normally used for carbon dating.
This activity would also be easy to adapt when talking about half-lives within a chemistry course. Also, review what a half-life is (info given the day prior during lecture/ notes/ reading).
New information needed to be introduced with parent and daughter isotopes.
The first post question caused some confusion: Why didn't each group get the same results?
A lot of the students said because they shook the containers differently... I also have students wash their hands before the activity, because of course after, the students eat the M&Ms. Radioactive decay and half-lives can be a very difficult concept for our 8th graders to grasp.
They not only enjoyed this activity, but they really gained a better understanding of it as well.