Seeing IS believing. Rocks are elastic!

The notion of rocks as elastic solids underpins many seismological concepts including the earthquake cycle and seismic wave propogation. This demonstration physically illustrates this property as students explore several rock/mineral specimens. The demonstration is somewhat discrepant because students' prior experiences suggest that rocks are hard and inflexible. Using this as a starting point, the demonstration begins with attempts to bend a large hand sample of granite or marble. Next, a large mica sample is deformed elastically. Finally, the elastic deformation of a long thin marble slab allows students to see and feel, that solid rocks are indeed elastic. During the discussion students are introduced to the concepts of stress and strain.

Objectives:

Students will be able to

  • Explain a method to demonstrate that solids, like rocks, can deform elastically
  • Describe, in a short paragraph, how the elasticity of rocks is fundamental to the earthquake cycle


Level: Novice

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