How I’m Imagining the Beginning of Forces Unfolding

Brain Dump.

Getting Started (Day One, at the end of another day really)

(1) Paige Keely’s Formative Assessment Worksheet (Individual, Group Discuss). Done this before, goes pretty well.

(2) Bowling Ball Challenge–whole class engagement, get ideas, puzzles, questions going. Have done this with outreach stuff, but not in class.

Exploration Before Reading (Day One)

(3) Hover Puck Activity (Words, Motion Maps, Graphs). Done this before. Goes pretty smoothly

(4) Revisit Statements from Worksheet– resolve what can be, and leave unresolved what can’t.

(5) Some remarks from me. Introduce notion of interactions, and the idea that forces come in pairs (but not that they are equal). Mention historical notions of “force impressa” and “force viva”, and how relates to how physicists now use the word force, and what it does and doesn’t refer to.

Reading (At-home)

(6) Selected Reading (The whole chapter should not be read. It’s really bad).

(7) Online Reading Questions to relate N1 and N2 aspect of reading to in-class observations with bowling balls and pucks. Other questions to explore common sense around N3rd Law, and not resolve. Questions to connect statements from reading to statements on Formative Assessment Worksheet. Questions to test their understanding.

Synthesizing and Stabilizing from Reading (Back in Class)

(7) Based on my assessment from student responses to #5, summarize key ideas and challenges I saw. Ask a few clicker questions that target key ideas and challenges. last few questions should be getting us toward skills / ideas for problem-solving so…

(8) Interactive Demo Problem (I mostly do, with stops for students to peer discuss)

  • Cart on Track:  Fan exerts force one way, pulling with string the other.
    • Not moving, using spring scale on string to get a measure of Force associated with Fan.
    • Predict acceleration of Cart with Fan Only. Check with Motion Detector.
    • Big goal here is to link concepts from reading to problem-solving in simple situation where we have a= 0 opposing forces, a > 0, single force.

Game Time-students in the driver seat again.

(9) White Board Problem (Extends what I did to a case where a > 0 with multiple forces)

Now pull cart with ~constant force with string greater than fan, and have TA note the value of force read by spring scale. Show them the velocity vs. time graphs. Ask them to determine how much force I was exerting.

    • 1st:  Best Guess, Too High, Too Low. On the front board.
    • 2nd: Have students share some ideas about getting started, information that might be important, challenges they anticipate, and what concepts from reading are relevant. All on front board.
    • 3rd: Have extension question ready–what would be different if I turned the fan around and pulled just as hard? What would graph look like then and why?

(10) Board Meeting Discussion. Lots more to say here about format, goals,etc.

(11) Don’t forget to reveal answer, and compare to our Best Guesses, etc. Celebration abound.

Assessment Time

(12) Standards-based assessment… Main questions will have students are given a graph of velocity vs. time, but it’s negative slope. Students are given all the horizontal forces they need. They’ll need to determine the mass. [Note: This is not a permutation we have not done]. Other questions will target more conceptual things related to common difficulties like F~v, etc.

(13) Students will self-assess at the back of the room. Turn in to me if they want additional feedback or want to submit work for evidence of mastering the standard.

Looking Ahead Time Troughts

Extend the concept of equilibrium to two-dimensions via a force table lab we have to do. Would love to do as VAD, but students in this class will be expected to do/know more with components. Do I have time to do both?

Extend the difficulty of problems to include non-perpendicular forces and ramps. This will be what their exam problems will look like.

Students will be reassessing on vector standards, and need to emphasize to them how important it is to work toward mastery of the vector standards.

Will be introducing friction in here too. Bridging Analogy stuff.

Instructor Concerns:

Haven’t really done anything with N3rd Law, beyond original intro of force pairs and reading/ reading questions…

Didn’t really talk about vertical forces, or Normal force understandings / mechanism. Where am I going to fold that in?


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