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A Pen-Based Statics Tutoring System

A Pen-Based Statics Tutoring System. Jack Lee Thomas Stahovich Robert Calfee Presented by: James Herold. Demo. Outline. Introduction Solving a problem System Boundaries Drawing/Critiquing Forces Writing/Critiquing Equations User Study Results Conclusion.

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A Pen-Based Statics Tutoring System

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  1. A Pen-Based Statics Tutoring System Jack LeeThomas StahovichRobert Calfee Presented by: James Herold

  2. Demo

  3. Outline • Introduction • Solving a problem • System Boundaries • Drawing/Critiquing Forces • Writing/Critiquing Equations • User Study • Results • Conclusion

  4. Textbook instructions for FBDs • Step 1: Decide what system to isolate. • Step 2: Next isolate the chosen system by drawing a diagram which represents its complete external boundary. • Step 3: Identify all forces which act on the isolated system… -- J.L. Meriam and L.G. Kraige. Engineering Mechanics - Statics. John Wiley & Sons, Inc., 6th edition, 2007.

  5. Typical Student Work

  6. Typical Student Work

  7. Solving a problem Create Boundary Draw Forces Write Equations CritiqueBoundary Critique Forces Critique Equations Done!!

  8. Creating a Boundary

  9. Critiquing Boundary:Statically indeterminate

  10. Critiquing Boundary:Cutting through rigid bodies

  11. Critiquing Boundary:Does not contain the force of interest

  12. Solving a problem Create Boundary Draw Forces Write Equations CritiqueBoundary Critique Forces Critique Equations Done!!

  13. Drawing a force

  14. Hierarchical Feedback Free body Diagram Errors + All interactions between the system and objects outside the system boundary must be represented by forces.

  15. Hierarchical Feedback Free body Diagram Errors + All interactions between the system and objects outside the system boundary must be represented by forces. • The missing force is at a roller support. +

  16. Hierarchical Feedback Free body Diagram Errors - All interactions between the system and objects outside the system boundary must be represented by forces. • The missing force is at a roller support. - • The missing force is at the highlighted location. -

  17. Video Explanations

  18. Buggy Rules Student FBD Correct Low-Level Errors Conceptual Diagnosis 1. “It appears that a body has been incorrectly modeled as a two-force member.” Force in Wrong direction. Missing 2 Forces.

  19. Buggy Rules W W Correct Student FBD Low-Level Errors Conceptual Diagnosis Forces are in the wrong direction. “Having a load does not cause all the forces to be in the opposite direction of it.”

  20. Solving a problem Create Boundary Draw Forces Write Equations CritiqueBoundary Critique Forces Critique Equations Done!!

  21. Writing an Equation

  22. Writing an Equation Type: Fx=0 Lever

  23. Writing an Equation Bx – D cos (u) = 0

  24. Matching Equations Student Equation - FCOS(U) + P SIN(U) = 0 ? Correct Equation - T COS(U) + F SIN(U) = 0

  25. Matching Equations Student Equation - FCOS(U) + P SIN(U) = 0 ? Correct Equation - T COS(U) + F SIN(U) = 0

  26. Matching Equations Student Equation - FCOS(U) + P SIN(U) = 0 ? Correct Equation - T COS(U) + F SIN(U) = 0

  27. Outline • Introduction • Solving a problem • User Study • Results • Conclusion

  28. User Study Pretest Posttest NP2 Tutorial • Participants: • 101 students, working in pairs • UC Riverside statics course • Sessions: • 4 through out the quarter • Study in 3rd Session -- 30 min with NP2

  29. User Study: Problems Problem A Problem B

  30. Improved Solution Time 32% Reduction Problem A Pretest Posttest 7.2 minutes 4.9 minutes 24% Reduction Problem B Pretest Posttest 7.3 minutes 5.6 minutes

  31. Solution Correctness: Problem A

  32. Solution Correctness: Problem B

  33. Ease of Drawing Easy Hard Boundary Arrows Labels

  34. Usefulness for Learning Very Useful Not Useful Equilibrium Problems Two-Force Member Newton's 3rd Law Forces Boundary Selection

  35. This Program… High Low Has Usable Feedback Is easy to learn Is preferable to WIMP

  36. Overall Reaction High Low Wonderful Terrible Easy Difficult Satisfying Frustrating Stimulating Dull

  37. Conclusion • Possible to scaffold handwritten work • Sketch recognition enables natural work environment … • Creating a solution rather than selecting the answer • Buggy-rules enable diagnosis of conceptual misunderstandings • NP2 is an effective tutorial system • Students like the interface • Measurable learning gains are quickly achieved This work is provided by the National Science Foundation via award No. 0735695. They also gratefully acknowledge support from HP, who provided the tablet PCs used in this project.

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