January 10, 2018 Filed in: Articles

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“What does your model assume about this situation?”

“That … the…friction is zero.”

“Since there actually is a small amount of friction, should your model's prediction be higher or lower than the measurement?”

“Umm… it should be a bit higher”

“Is that what you observed?”

“Yes.”

“If you wanted to improve your model, what else could you measure about the system?”

“I could measure the amount of friction.”

Consider how far we have come from a traditional plug and chug question to find the acceleration. All of this begins on day 4 of grade 11 physics when we meet Penny.

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As we continue through the motion unit, we return to the race data and examine it through the lens of new physics ideas, like position graphs:

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speed or velocity graphs:

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Students are mark driven: don’t oppose this, use it. Just make sure the marks are encouraging productive behaviours. One day, when their fever breaks and they wake up from their mark-driven stupor, they will hopefully discover that they have been practicing the habits and skills of the life-long learner.

“Never make a calculation until you know the answer. Make an estimate before every calculation, try a simple physical argument (symmetry! invariance! conservation!) before every derivation, guess the answer to every paradox and puzzle. Courage: No one else needs to know what the guess is. Therefore make it quickly, by instinct. A right guess reinforces this instinct. A wrong guess brings the refreshment of surprise. In either case life as a spacetime expert, however long, is more fun!”— John Wheeler

Our students should do this too! This is great exercise for developing one’s physical intuition and common sense about the numbers involved with physics. Now, our students won’t begin with the sophistication of the person who coined the term “black hole”; they start much simpler. Training begins in the third lesson of grade 11 where students estimate simple measurements and estimate calculations based on those measurements.

Estimations become integrated into our routine problem solving process, giving students two years of regular practice with Wheeler’s advice. In grade 12, the estimation skill is enhanced with Fermi problems.

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In physics, we always use mathematics with a purpose in mind, and each step in a lengthy solution will have a unique purpose that contributes to the final result and these should be described. This not only helps students clarify in their own minds the purpose of their mathematical work, it greatly increases the readability of the final product. It is now pretty rare that I have to search through a page of scribbled symbols to find the next step in a student’s solution.

- The New Introduction and Motion Unit (http://www.meyercreations.com/physics/resources/New%20motion/11%20Handbook%20-%201%20Motion.pdf)
- A New Force Unit that continues the modeling theme (www.meyercreations.com/physics/resources/New%20motion/11%20Handbook%20-%202%20Forces.pdf)
- Sample Answers for student self-evaluation (www.meyercreations.com/physics/resources/New%20motion/11%20Handbook%20-%20Self-Eval%20Exemplars.pdf)
- Brain Lessons (www.meyercreations.com/physics/resources/New%20motion/Brain%20Lessons.pptx)
- Course Guides (http://www.meyercreations.com/physics/resources/New%20motion/Course%20Guides.zip)

- I learned about it from the work of Eugenia Etkina, for example: https://drive.google.com/file/d/0By53x8SYAF1lRVdJcnZiSVNYaXM/view
- Thanks to Roberta Tevlin for the 4C’s idea for assessing written responses.
- Ericsson, K. Anders, Ralf T. Krampe, and Clemens Tesch-Römer. "The role of deliberate practice in the acquisition of expert performance." Psychological review 100.3 (1993): 363.
- Thanks to David Harrison at U of T for highlighting the importance of Wheeler’s suggestions.