In a conversation about Energy Theatre (From E1 110810 0820 T4 35:03-36:46) or the Useful.Energy Episode attached below, I was struck by this conversation about how useful energy is depending on its form. Jessica (the first to speak) suggests that students might not understand that once you do energy theater, "You can't go backward." Azzam later comes up with the word "irreversible" that helps to describe what Jessica was trying to say. She makes the suggestion that perhaps students should follow this rule:
“The more useful the energy is, the taller you stand.” Jessica was not changing the amount of energy, but I fear that this suggestion may lead to an expectation that then heat or sound is not as 'good' as kinetic energy and/or amount changes with size change and/or lesser energies "count for less." I feel like it depends on the purpose of the energy transfer. What are your thoughts about this idea?
Following this idea, Kimberly tries to give an example of heat being useful (when you burn coal), but Jessica says, "But, what's useful is, you know like, burning coal heats water, the steam turns the turbine, so what's really useful is the mechanical energy of the turbine moving." But this example is completely contradicting her first statement because heat IS useful in this example. Azzam goes on to describe that the usefulness of energy is related to how much of it we can control. I find this example to be really interesting - that we "control" energy. That it is like a stallion, wild, but tamable in some situations. Is this different than thinking of energy as a substance? (a live substance?) (a substance with a mind of its own?) (a substance with an agenda?)
I think this is a really interesting idea and Ingrid's comment about entropy reminded me about Amy's post about the idea of thermal energy always increasing (http://scherrenergyproject.blogspot.com/2011/08/reflections-day-one-energy-two-amy-two.html).
ReplyDeleteI wonder why this year's teachers are talking so much about the usefulness and value of energy! Did last year's teachers do that as well? Warren Christensen has been looking for teachers' implicit talk about entropy in last year's video, but he has pretty much come up empty, as far as I know. I was looking for a blog post about it, but unfortunately couldn't find one... Maybe Rachel can shed some light on this issue?
ReplyDeleteOh, and I really like the stallion analogy, btw ;-)
ReplyDeleteThis is a fascinating topic! I think it would be really interesting to have a discussion with students (of any age) about when energy becomes irreversible or no longer useful. I can imagine all kinds of scenarios that could be discussed as they try to iron out when thermal energy is useful or not useful, when it can be transformed back into another form or when it can't...and how to represent this in Energy Theater. What jumped into my mind was an image of students laying down when their form of energy was no longer useful (b/c this would signify that they could no longer mover around), although I can see the concern with them thinking that their amount of energy had changed somehow.
ReplyDeleteWhat an interesting post! I will be a Scholar this summer (2013), so all of this is new to me. But I want to respond to this one.
ReplyDeleteI feel that the "usefulness of energy" is, for better or for worse, a common starting point for most people when considering energy transfer and transform. Since there's no avoiding it, we need to learn how to best use the examples students (and teachers!) come up with, and more importantly (maybe), have a toolbelt filled with easier-to-start-with examples. For instance, an example I want to consider more this summer is one that I often give my students. When describing that thermal energy always increases and is "lost" to us (as useful energy), I then counter my own statement with the example of a Prius (which I happily own). The Prius takes the thermal energy of braking and charges the battery (regenerative braking). This is a case of thermal DECREASING and electric (or simply chemical) energy then increasing again. However, I stop there because in the past I've wanted to avoid cases of thermal energy decreasing. It's hard enough to get students to realize it usually increases! BUT, maybe I should give my students more credit and allow them more time to think about this interesting example. Maybe giving extra consideration to "special cases" will nail down the "typical cases" for them.
Getting to the question of whether or not to act-out the "usefulness" of the energy, my gut reaction is NO. It adds complexity to the model. Complexity is not inherently bad, but a somewhat subjective complexity might be dangerous. However, an interesting possibility might be to segregate "reusable thermal energy" from "lost thermal energy." This will depend on the efficiency of a given recovery system. Instead of having people stand up tall or lay down, the usable and nonreusable would be completely different people. This would utilize the ET model as it is without needing to add new components. (Take all of this with a grain of salt. I have not actually experienced ET yet. I am only currently reading the papers about it now!)
Another example of decreasing thermal energy, apart from Brad's on the Prius, are endothermic processes, spontaneous processes to which heat has to be added.
DeleteAn example is mixing table salt and ice slush. It requires energy to break the bonds in the ice, and the salty water reduces in temperature (quite a lot), so the thermal energy decreases.
I agree with Brad that my gut feeling is that maybe it adds too much complexity to bring usefulness to the ET, and that it might be geared for other representations, offering their own set of affordances.
In E2, Tues 130806, Rachel brought to discussion what different graphical representations bring forward vs. what they hide.