Radioactive Dice

Summary

In this activity, students will examine a population of dice as it changes over time (several rolls) and experiences “decay” per the same probabilistic rules that govern the radioactive decay of radioisotopes. Students will empirically or mathematically determine the half-life of radioisotope (radio-dice-otope?) uranium-238 and can go on to apply the what they learn to the problem of uranium-lead radiometric dating - the principal method that geologists use to determine the absolute age of some of the oldest rocks on Earth.

Activity Structure

This activity is based around an experiment conducted as a class that simulates the radioactive decay of uranium-238 into lead-206 by using a large number of dice. In addition to this core activity, you may elect to add one or more optional add-ons, depending on your objectives.

Core Activity

Each student will record and interpret the results of this experiment on their Experiment Data Sheet handout. Then, they will transfer this data to their Data Interpretation handout where they will graph and qualitatively described the shape of the resulting exponential decay curve.

Add-ons

After the core activity has been completed, you may elect to examine the subject of Radiometric Dating, either from a Graphical approach (designed with 8th grade math-language in mind) or a Quantitative approach that examines and manipulates the associated exponential and logarithmic equations. Additionally, you might have your students take a closer look at the mathematics of the simulation itself by implementing the Functions and Modeling add-on (recommended for use in M3 and AFM classes).

Structure Summary

NCGS 12-Sided Radioactive Dice Kit

This activity is designed around the NCGS 12-sided Radioactive Dice Kit. Three such kits are available for loan to educators in North Carolina. Please contact Outreach Geologist Will Blocher if you are interested in borrowing one of our kits.

If you would prefer, a version of this activity is also available that has been calibrated for use with standard 6-sided casino dice.

Why are these special dice better?

• More sides means the exponential decay curve is revealed over more rolls. It's like taking a picture with a high-resolution camera. The curve approximated by standard dice is more "pixelated."
  
• Rolling a large group of 12-sided dice is easier. They are more likely to roll around in a tray, whereas standard dice are prone to sliding.
• In a large group of standard dice, it can be hard to pick out all the dice that have landed on a given side. With only one marked face, these dice are easier to spot and remove when they "decay."
• They look cool! (we think)