Discrepant events


  • A discrepant event is something that does not turn out as expected. It can be used to challenge students' beliefs and makes them more receptive to learning what you want them to learn. It can be combined with the conceptual change method.
  • Discrepant events can be presented as a hands-on activity, a demonstration. a toy, an image (see this one) or a video (check YouTube or TeacherTube). At a minimum, students should have a mental model of what they expect to happen. The discrepant event will generally not turn out as expected and students are left with cognitive dissonance.
  • Steps:
  • • Focus student attention without giving any hint of what to look for
  • • All students observe the event
  • • Give students time to think, compare, question, consider and explain.


  • DiscrepantEvent.jpg
  • This example uses a T-chart with three things the student must write: describe the experiment, make observations and explain observations. Another format is predict what will happen, describe what happened and explain your observations.


  1. Whelmers (from MCREL, has a number of well-developed discrepant events)
  2. The Exploratorium hands-on activities
  3. How to Teach Science (discussion of discrepant events)
  4. Tik Liem's Invitations to Science Inquiry book (warning: the whole book, a huge, scanned pdf file, over 400 pages)
  5. The motivational power of discrepant events (discussion and examples)
  6. Best Teaching Practices (description, additional references and links)
  7. Examples of discrepant events
  8. Discrepant events, complete with teacher guides (scroll down in the right column)
  9. Holt, Rinehart & Winston professional reference for teachers (pdf file, has several examples)
  10. Discrepant event demonstrations (article from The Science Teacher, scanned pdf copy)
  11. Another list of discrepant events
  12. Discrepant events in physical science (Word document)
  13. BioChem demos from the Access Excellence collection
  14. Google "discrepant event" + whatever topic you are looking for