Radioactive Decay Activity using Pennies

This site is an activity simulating radioactive decay using pennies. Good activity illustrating half-life.

Standards & Objectives

Academic standards
CLE 3005.6.2
Analyze the organizational structures of 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: 

Learning Goals:

  • to illustrate the exponential nature of radioactive decay
  • to demonstrate the concept of half-life
  • to establish the randomness of radioactive decay
  • to illustrate the concept that quantity determines the number of isotopes that decay

Lesson Variations

Blooms taxonomy level: 
Differentiation suggestions: 

If your class is particularly large, you might want to have a few students help you count the "undecayed" isotopes. This demonstration is a great way to break up the lecture with a short activity – students get to stretch their legs. I often give students the penny at the beginning of class with no explanation – or say something like, "Today, you're getting paid for coming to class!" After introducing some of the concepts involved in radioactive decay, I do the demonstration. I usually let them keep the penny at the end of the class.