In this activity, students explore small doses in the order of parts per million. They dilute food colouring to help them understand how small one part per million actually is.

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

  • make a liquid measure of one part per million
  • recall the meaning of the term part per million (ppm)
  • explain the relationship between ppm and ppb
  • explain that small concentrations can be in substances without being visible
  • explain the importance of being accurate when making measurements in science.

Download the Word file (see link above) for:

  • introduction/background notes
  • what you need
  • what to do
  • student handout.
    Published 4 September 2012