PHYSICAL EXPERIMENT ON ELASTIC AND NEWTONIAN RHEOLOGY
Summary
Simple physical models with rubber sheet (elastic rheology) and clear silicon putty (silicon "goo"; linear viscous rheology) help students conceptualize and describe quantitatively strain and stress in rheologically distinct materials.
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Context
Audience
The activity is used in undergraduate structural geology (course in geology and geological engineering majors).
Skills and concepts that students must have mastered
Students must understand basic concepts of strain, stress, and rheology (elastic and linear viscous). The activity should therefore be implemented after the students have been taught the corresponding chapters from a structural geology textbook. The math required is basic algebra.
How the activity is situated in the course
The activity comprises a stand-alone exercise during a lab (three hours per week).
Goals
Content/concepts goals for this activity
The goals of the activity are:
1) Compare strain axes orientations in pure shear vs. simple shear
2) Describe stress and strain in materials with elastic vs. linear viscous rheology
3) Quantitatively relate strain, stress, viscosity, and strain rate
4) Visualize finite vs. infinitesimal strain
1) Compare strain axes orientations in pure shear vs. simple shear
2) Describe stress and strain in materials with elastic vs. linear viscous rheology
3) Quantitatively relate strain, stress, viscosity, and strain rate
4) Visualize finite vs. infinitesimal strain
Higher order thinking skills goals for this activity
The activity helps students synthesize key concepts about stress and strain (infinitesimal and finite). Students have to draw parallels between deformation of the analogue materials and deformation in the lithosphere.
Other skills goals for this activity
Students have to work in groups.
Description of the activity/assignment
To prepare for the activity, students do background reading on rheology from structural geology textbook. In the lab, students are provided with the required analogue model materials (rubber sheets attached to aluminum grips, silicon goo, and straw). Their task is to apply specific type of deformations on the materials, make measurements, and calculate properties of the deformation.
Determining whether students have met the goals
The provided worksheet answers (qualitative and quantitative) are used to evaluate students' understanding of concepts addressed.
More information about assessment tools and techniques.Teaching materials and tips
- Student Handout for Elastic and Newtonian Rheology (Acrobat (PDF) 114kB Jul13 15)
- Instructor information for Elastic and Newtonian Rheology (Microsoft Word 4.3MB Jul13 15)
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Other Materials
Supporting references/URLs
Hobbs, B.E., Means, W.D., and Williams, P.F., 1976. An outline of structural geology. John Wiley & Sons, Inc., New York, New York, p. 571
Means, W.D., 1976. Stress and Strain: Basic Concepts of Continuum Mechanics for Geologists. New York, Springer-Verlag, p. 339
Means, W.D., 1976. Stress and Strain: Basic Concepts of Continuum Mechanics for Geologists. New York, Springer-Verlag, p. 339