Activity

Radioactive decay

In this activity, students model the radioactive decay process for carbon-14 by flipping coins. Each coin represents a carbon-14 atom, and if it lands tails up when flipped, this indicates radioactive decay.

Graph of a radioactive decay curve for carbon-14.

Radioactive decay

The graph shows a radioactive decay curve for carbon-14. A plot of the activity of the sample versus time shows that the half-life for carbon-14 is 5,730 years.

Rights: The University of Waikato Te Whare Wānanga o Waikato

By the end of this activity, students should be able to:

  • appreciate the randomness of radioactive decay

  • describe the concept of half-life

  • explain the exponential nature of radioactive decay

  • relate the radioactivity features of half-life, exponential decay and randomness to C-14 dating of artefacts.

Download the Word file (see link below) for:

  • introduction/background notes

  • what you need

  • what to do

  • student worksheet.

C-14 carbon dating process

Historical artefacts like moa bones can be dated using a technique that measures the activity of the radioisotope carbon-14 still present in the sample. By comparing this with a modern standard, an estimate of the calendar age of the artefact can be made.

To use this interactive, move your mouse or finger over any of the labelled boxes and click to obtain more information.

Rights: The University of Waikato. All rights reserved.

Published: 9 December 2011