Wednesday, November 29, 2006

 

Physics Problem Solving

The following is a summary I wrote of professional research into how experts go about solving physics problems, contrasted with how novices solve the same problems. I can dig out the reference for the original (quite lengthy) review paper, but don't have it handy. I thought the findings were quite interesting.

I gave this to my Intro Physics students, with a note saying, "Your goal as a student should be to move from the novice column to the expert column. Notice how expert problem-solvers stop to think about the problem, draw pictures to visualize the problem, plan out their strategy, before beginning, etc.--and still manage to solve problems much faster than novices. Short-cuts aren't always short!"

1. Novice: Studies worked examples rapidly, without bothering to understand the examples.
Expert: Studies worked examples until sure examples are understood.

2. Novice: Consults worked examples later in hopes of finding a plan.
Expert: Consults worked examples later to verify that chosen plan is correct.

3. Novice: Subject knowledge is lacking.
Expert: Has a thorough knowledge of subject matter.

4. Novice: Collection of knowledge is a random jumble of miscellaneous facts.
Expert: Collection of knowledge is well organized in person's head: centered around physical principles and hierarchical (topic trees).

5. Novice: Separates intuition/"real world" knowledge from theoretical/formal knowledge.
Expert: Has integrated real world with theoretical knowledge.

6. Novice: Not able to "translate" problem statements.
Expert: Able to correctly infer situation from the given information.

7. Novice: Little or no planning before trying to solve equations.
Expert: Develops a definite problem-solving strategy before starting to solve equations.

8. Novice: Not able to construct a physical picture of what's going on, or is unable to recognize when chosen picture is inappropriate.
Expert: Constructs a useful physical picture of the problem.

9. Novice: Does not stop to think of a qualitative answer before starting to solve the problem.
Expert: Uses qualitative physics principles/physical reasoning to have a reasonable answer to the problem in mind before beginning to solve numerically

10. Novice: Focuses on surface structure (physical items involved in problem).
Expert: Focuses on deeper structure (physical laws involved in problem).

11. Novice: Generates several physical models at start, and sometimes shifts models midstream because not certain of correct way to look at problem.
Expert: Develops one model at a time; additional models only are used to check solution of first model, or if first model doesn't seem to be working

12. Novice: Works backward (looks for equation that has the unknown in it).
Expert: Works forward (looks for equations that include the given quantities).

13. Novice: Does not stop to think about the answer that was obtained.
Expert: Stops to think if answer makes sense (checks against qualitative answer)

14. Novice: Spends a lot of time working on problem.
Expert: Solves problem quickly.

15. Novice: Unaware of understanding gaps.
Expert: Recognize when something is not understood.

Comments:
I really enjoyed this. I've read similar research in problem solving in general--not specific to physics. I use those same principles in my math classes (especially calculus) as well. Do you have a link to the research article you're summarizing?
 
Not a link, but here's the reference: It's from chapter 12 of _Handbook of Research on Science Teaching and Learning_, edited by Dorothy L. Gabel, publised by MacMillan Reference Books, 1994. Hopefully you can find it in a library, because it's apparently not available from amazon.com.

Chapter 12 was written by David P. Maloney of Indiana University and Purdue University-Fort Wayne, is 28 pages long (small print!), and summarizes 79 research papers in the field. These 15 points were my summary of his summary, so to speak--although he had other things in his review article unrelated to the novice/expert issue.

I'd bet some other chapters would interest you as well, but that's the chapter I've read in the most depth.
 
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