1. Teaching displacement concepts using computer programs Skylar L. Primm and Basil Tikoff November 9, 2004 Skylar L. Primm and Basil Tikoff November 9, 2004

2. Introduction  Problem: –Stress and strain are hard concepts for students in introductory structural geology courses to grasp –Difficulty in visualizing progressive deformation is a prime reason  Problem: –Stress and strain are hard concepts for students in introductory structural geology courses to grasp –Difficulty in visualizing progressive deformation is a prime reason

3. Introduction  Problem: –Interactive computer programs have been successful at demonstrating these concepts to students –These programs were written for legacy systems and no longer work on modern computers  Problem: –Interactive computer programs have been successful at demonstrating these concepts to students –These programs were written for legacy systems and no longer work on modern computers

4. Introduction  Our Solution: –Rewrite these programs, improving and updating them for modern PCs –Add new programs to the suite, covering a wider range of displacement concepts –Utilize the Java programming language for maximum compatibility –Make the programs downloadable  Our Solution: –Rewrite these programs, improving and updating them for modern PCs –Add new programs to the suite, covering a wider range of displacement concepts –Utilize the Java programming language for maximum compatibility –Make the programs downloadable

5. RotationDistortionTranslation Displacement Fields Rock Fabric Finite Strain

6. Rotation Translation Shear Fabric Rotating Clasts Flow Lines Distortion Shear Box Stress v. Strain Strain Theory 3D Strain

7. Shear Box  2D v. 3D  Main Point: Progressive finite strain  Relevant Concepts: –Finite strain –Progressive distortion and rotation of material lines  2D v. 3D  Main Point: Progressive finite strain  Relevant Concepts: –Finite strain –Progressive distortion and rotation of material lines

8. Shear Box

12. Stress v. Strain  2D v. 3D  Main Point: Difference between axes of stress and finite strain  Relevant Concepts: –Finite strain –Stress (assuming viscous medium)  2D v. 3D  Main Point: Difference between axes of stress and finite strain  Relevant Concepts: –Finite strain –Stress (assuming viscous medium)

15. Strain Theory  2D v. 3D  Main Point: Synthesis of advanced concepts in progressive finite strain  Relevant Concepts: –Finite strain –Infinitesimal strain –Flow apophyses –Kinematic vorticity  2D v. 3D  Main Point: Synthesis of advanced concepts in progressive finite strain  Relevant Concepts: –Finite strain –Infinitesimal strain –Flow apophyses –Kinematic vorticity

17. 3D Strain  2D v. 3D  Main Point: 3D progressive finite strain  Relevant Concepts: –Non-plane strain –Constriction / Flattening  2D v. 3D  Main Point: 3D progressive finite strain  Relevant Concepts: –Non-plane strain –Constriction / Flattening

18. 3D Strain

22. Rotating Clasts  2D v. 3D  Main Point: Rotation of elliptical clasts under progressive finite strain  Relevant Concepts: –Jeffery v. March model rotation –Ellipticity  2D v. 3D  Main Point: Rotation of elliptical clasts under progressive finite strain  Relevant Concepts: –Jeffery v. March model rotation –Ellipticity

23. Rotating Clasts

25. Flow Lines  2D v. 3D  Main Point: Translation of material points under progressive finite strain  Relevant Concepts: –Particle flow paths –Flow apophyses  2D v. 3D  Main Point: Translation of material points under progressive finite strain  Relevant Concepts: –Particle flow paths –Flow apophyses

27. Shear Fabric  2D v. 3D  Main Point: Generation of rock fabric under progressive finite strain  Relevant Concepts: –Translation –Rotation (Jeffery model)  2D v. 3D  Main Point: Generation of rock fabric under progressive finite strain  Relevant Concepts: –Translation –Rotation (Jeffery model)

28. Shear Fabric

31. Teaching Techniques  Combined with physical models, these programs create a bridge between tactile and mathematical learning  These programs can also act as a self- check for labs or homework assignments  Background information is available within each program, with references  Combined with physical models, these programs create a bridge between tactile and mathematical learning  These programs can also act as a self- check for labs or homework assignments  Background information is available within each program, with references http://www.geology.wisc.edu/~skylarp/java.html

32. Conclusions  Based on our experiences with one semester of introductory-level students, these simple computer programs are an effective tool for enhancing students' comprehension of basic displacement concepts http://www.geology.wisc.edu/~skylarp/java.html

33. Acknowledgments  UW - Madison Structure Group  NSF Graduate Research Fellowship Program  UW - Madison Structure Group  NSF Graduate Research Fellowship Program http://www.geology.wisc.edu/~skylarp/java.html