Brittle vs. Ductile Rocks

A candy bar, made almost entirely from nougat, is a useful model for exploring how temperature affects a rock's response to stress. Together with their teacher, students compare the candy bar's response to stress to other materials explored previously (e.g. rubber bands and Marble Tongs). From this they see how different materials respond to the same stress. Building on this, students also explore how temperature can affect the deformation of the same material undergoing the same stress. The discussion at the conclusion of the demonstrations ties the concepts of deformation to faulting (earthquakes) and folding of rocks.


Students will be able to:

  • describe common examples of materials that exhibit brittle, ductile, and elastic deformation
  • correctly identify images of faults and folds
  • describe at least one way that the conditions of formation may have differed for faulted rock vs. folded rock

Total Time: 15min
Level: Novice

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