System Schemas

I have been practicing the Modeling Method for 14 years now with varying degrees of success. I have been leading modeling workshops now for 4 years (this summer is actually my 5th year) and I learn so much in my time.

This year I am running the workshop in Muskegon, Michigan.  Since I am not in Detroit, I am working with a new co-faclitator. Her name is Laura Sloma and she is AWESOME!  She teaches at East Kent Wood High School just outside of Grand Rapids and is a seasoned practitioner of the Modeling Method.  I love working with her and it is great that we gotten to share our ideas.  I've already learned so much from our interactions.

The biggest addition to my knowledge and procedure has been the introduction of SYSTEM SCHEMA to the force unit.

I never got this.  I have read it in some Hestenes literature namely, "Modeling Methodology for Physics Teachers" but it was decontextualized and too abstract for me to see how it would apply in actual practice.  A couple of years ago a teacher that I work a lot with in the Detroit area brought these to my attention. I didn't see how they could enhance student understanding and I thought they would actually work against me in that they seemed more abstract than the force diagrams themselves.  

After working with Laura, my co-facilitator, who has been using them for years (since 1998) I realize the value.  The system schema area a precursor to a force diagram!  The students list the physical objects in the interactions and construct the force diagrams from there!  So as a student, even if you don't get the whole "dot and arrow" thing the system schema gives you a place to start to analyze any situation.  

In addition to jump starting a force diagram, the system schema help us to understand the N3LFP!  Every line connecting the circles on a schema is an interactive force pair!   And the number of lines drawn to each circle is the number of forces on that object.

One aspect that the participants haven't really noticed yet is the fact that if every line is an interactive force pair then even the lines drawn from the "Entire Earth" to an object must also be a force pair.  What does that mean; that if the Earth pulls a box down the box pulls the Earth up with the same force?  I can't wait until they notice!

These are a revelation!  I have never used them with my students but I'm going to this year.  I can see what a positive impact they have had on the participants and I am excited to see