Teacher freedom to represent energy stories the way they want

Monday E1 was considering a bowling ball lowered at constant speed.  They had spent the first part of their afternoon doing Energy Theater for it.  One conclusion from that ET was that the energy story for raising the ball at constant speed was different than for lowering the ball at constant speed.

For the rest of the afternoon Lane asked them to draw representations of the ball up and the ball down to compare and contrast and try to answer four statements he put on the screen at the front of the room about chemical and thermal energy.  Here’s one example of his four questions:

“Is it possible that the two scenarios require different amounts of chemical energy and generate different amounts of thermal energy?”

What was interesting to me was that in response to these different questions, different groups produced entirely different representations.  One group used Energy Tracking Diagrams:  

One group (made of two tables working together) used Energy Bar Diagrams that they had read about in a paper for homework and apparently modified for their own use here:  

And a third group used a table of numbers to make their case (or two different tables of numbers, with one group member doing her own work down at the bottom of their board separate from what the other three members of the group were doing at the top):

My idea is that this data supports Rachel's claim in her paper “Energy Tracking Representations” about teachers accepting the instructors invitation to “invent new representations of energy… to conserve and track energy in complex real world scenarios.”

The teachers seem to feel free to choose or create a representation they find most useful to answer instructor questions.  And in the case of Energy Bar Diagrams, tables #3 and #6 teamed up together and apparently modified something they had read about previously for the course that I’m not sure had yet been used in the class.  Perhaps someone who has been watching E1 the first week in the afternoon could comment on where they might have seen Energy Bar Diagrams previously.  I'm not sure tables of numbers have appeared previously or not either.

Very Cool!!