Forms of Energy Part 3 - discussion of names and separation

On Tuesday afternoon Eleanor had the class (as a large group) fill in a table about forms of energy. One column had forms of energy (motion, heat, sound), and the other column said "How do we know it's that form?" This was a fascinating discussion, with lots of concern about the names of forms of energy and when to distinguish things as different forms or lump them together.

Regarding names, teachers kept asking what the "scientific" names were, which names they should use, and whether it was OK for their kids to use certain names. There was definitely a sense of deferring to authority: they wanted Eleanor to give them the ANSWER. Someone asked about the term mechanical energy, and Eleanor said that she doesn't find it useful and it's not in the standards. In response, one teacher talked about having to "sanitize" otherwise good curriculum that used that word. Most of this discussion was definitely in the realm of my category 1 - categorical.

Then they got into a great discussion about whether sound energy was the same or different from motion energy. There seem to be two threads of argument here: one about whether you can actually hear the sound - if it's too quiet to detect is it still sound energy? - which they resolve quickly (category 2 - evidence), and another about whether there is anything to sound other than the motion of molecules (category 3 - mechanism). Heather says to resolve this, they would need to find out whether sound travels in a vacuum. If it does, then sound energy is a different kind of energy than motion, because it can exist independently of the motion of air molecules. If not, it's not. Eleanor offers to set up the experiment during the coffee break, but then it turns out that the vacuum pump is broken, so she shows them a youtube video instead, demonstrating that if you put a bell in a bell jar and pump all the air out, you can't hear it anymore. After seeing this, at first most people want to say that sound energy is not a distinct form of energy, but after a long discussion with many meandering tangents, a discussion of how the air molecules are vibrating rather than actually going anywhere (category 3 - mechanism), and lots of discussion about the distinction between energy and objects, they conclude that the question of what's a separate category and what's not is really complicated!