Relative dating of rocks activities
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).
Students use M&Ms to demonstrate the idea of radioactive decay. Parent isotopes are represented by the M side up (radioactive).
Paul, MN, based on an original activity retrieved from also with the help of Jenni Johansen (other 8th grade science teacher at So. Paul Junior High School In this activity, students gain a better understanding of radioactive dating and half-lives.
As far as mastery of content, this activity is done in our rocks and minerals unit.
Students should have some prior knowledge of rocks and how they are dated. Materials Needed: -100 M&Ms (per group) -Notebook -Piece of Paper -Plastic Container with a Lid Lesson should be introduced by reviewing the 2 broad ways scientists age rocks (relative dating and radioactive dating).
Daughter isotopes are represented by the M side down (stable).
Students begin by pouring the 100 M&Ms on the table, and set aside the "stable" isotopes (M side down).
They then gather the radioactive, or M side up M&Ms, put them back in the container, and then pour them out again. and continue this process until all M&Ms are stable, or M side down.
Equipment that is necessary is M&Ms– a lot because each group needs to begin with 100, and a container with a cover for each group.
Students should have the skill to set up a data table and a graph, however, if you want to use this activity with students that have not, you can provide them a template with that information.
Once all groups finish, each group records their info on the class decay table (on the board) and we calculate the averages of the class. Isotope Concepts: Students should begin to see the pattern that each time they dump out their M&Ms, about half become stable.
Once this info is calculated, students create a graph comparing the class average of parent isotopes to the number of half-lives. Students will be able to explain what a half-life of a rock is. Students will have a more in-depth understanding of what radioactive decay is. Students will understand how scientists use half-lives to date the age of rocks. Students then should be able to see the connection of the M&Ms and radioactive elements in rocks, and how scientists can determine the age of rocks by looking at the amount of radioactive material in the rock.
Skills: -critical thinking -data analysis -questioning -graphing and data collecting Vocab Words: 1. This activity can be adapted for older students, but is used in an 8th grade earth science classroom.Class size can vary, but activity should be done in groups of 2-3.