E2 Day 4 afternoon summary

I believe I have not posted summaries for afternoons 2 or 3, sorry.

This afternoon started with a continuation of the magnets discussion from the morning.  One side of the room (Bellevue colleagues, led by Matt and Lisa) advocated for negative potential energy which increases to zero at infinity, and the other side of the room (primarily Lezlie, Linda, and Mary Sue) argued for the idea that as you keep adding potential energy, it gets bigger and bigger (positively).  They eventually drew two graphs of PE vs. distance, one positive and one negative but both increasing and both leveling out at the top.  In an hour-long argument, which was an absolutely killer interchange IMO, they pretty much came to understand one another's arguments, and decided that in order to choose between the two graphs, they would need to locate an experiment that depended on the value of the PE at a point rather than the difference in PE between two points.  This was all the closure they required.  The discussion was really explosively awesome on multiple levels:  the physics issues, the scientific argumentation that took place, the details of the way the instructor (Hunter) managed the discussion, the different roles taken by the teachers (like when Lisa went all "teacherly" on Lezlie).  Whose dissertation is this??

After a much-needed break, we enjoyed Eleanor's AAPT talk, and then discussed the rock cycle video in preparation for reading that paper and case study tonight.  These felt like pleasant changes of pace.