Radioactive Decay Activity

This is a link to an activity that simulates radioactive decay using M&Ms and skittles. This is a good activity to help students understand half-life.

Standards & Objectives

Academic standards
CLE 3005.6.3
Read, interpret, and analyze graphics that support complex informational and technical texts.
CLE 3221.3.2
Analyze chemical and nuclear reactions.
Alignment of this item to academic standards is based on recommendations from content creators, resource curators, and visitors to this website. It is the responsibility of each educator to verify that the materials are appropriate for your content area, aligned to current academic standards, and will be beneficial to your specific students.
Learning objectives: 
  • To demonstrate that the rates of decay of unstable nuclei can be measured, that the exact time that a certain nucleus will decay cannot be predicted, and that it takes a very large number of nuclei to find the rate of decay.
Essential and guiding questions: 
  • What important discovery was made by Wilhelm Roentgen?
  • What material did Antoine Becquerel work with in his own investigations of X rays?
  • What did Becquerel discover through his experiments?
  • What two elements were discovered by Marie and Pierre Curie?
  • Why is Ernest Rutherford considered the father of nuclear physics? List Rutherford's major achievements.
  • In your own words, what do we mean by nuclear decay?
  • What do you think is emitted during radioactive decay?
  • What is the chance of getting heads on any flip?
  • What do we mean by random?
  • How many nuclei will be left after the second half-life?
  • How many would you predict will be left after the third half-life?

Lesson Variations

Blooms taxonomy level: 
Extension suggestions: 
  • The IAEA News Center is the public information and news service of the International Atomic Energy Agency on the Internet. Links to all IAEA online services can be found here. Visit this site for more information about strontium-90 and about the nuclear accident in Chernobyl in 1986 and its aftermath.
  • The Photograhic Periodic Table of the Elements can be used to find all the known isotopes of all the elements, their decay modes, and half-lives.

Helpful Hints

For each pair of students, you will need:

  • a cup containing about 80 small candies such as plain M&M's® or Skittles®
  • a paper towel