Conceptual understanding vs Equations (Afternoon ET 08-09 saga - part 1)

I've been trying to focus my attention to the two ET videos that I have from last week (Thursday and Friday afternoon). I got interested in these videos because the dynamics were so different from each other. I wan to analyze them in detail to understand the differences. So my following posts are going to be related with this story.

So, while watching Friday ET dynamics I found an interesting video from Trevor while talking with Rob. They  are debriefing in what happens while lowering a bowling ball at a constant speed. Rob is trying to figure out what type of energy is acting on the ball opposing the fall of the ball (due by the hands).

[00:00:01.00] Rob: My... chemical energy... My question was if there's force moving in the opposite direction of movement,
[00:00:11.12] Rob: a force is acting on an object opposite direction of movement what type of energy is that?
[00:00:19.05] Rob: and I, given to that it must be thermal energy, resistant sort of like
[00:00:25.05] Trevor: I feel like if I was doing it in... with math in -in -in my classroom I would have made it a negative sign.
[00:00:31.22] Trevor: Like would have had a negative sign for no reason (Rob: aha) (Woman: *laugh* just, no reason)
[00:00:35.02] Trevor: Because that is going in the opposite direction. And that would made all my equations work out beautifully

What is there to discuss?
I consider there is more than one thing going on here. So I invite everyone to engage to whatever thing you consider interesting to discuss, or propose another discussion thread.

Conceptual understanding vs Equations
This PD has been focused on conceptual understanding of energy rather than a numerical analysis. Here we observe how Rob is engaged in understanding how to address in the energy representation the effects of a force opposing the movement. While Rob talks, Trevor does not engage with Rob analysis, and instead explains how he would do it with math in his class. He says that by having a negative sign the equations would work according to what it is suppose to happen, but he doesn't present a reasoning in his decision. There is an actual laugh as a reaction to this "no reason" negative sign.
I consider changing the way to understand energy (and other topics) from a quantitative analysis into a conceptual needs a willing to make the change. Trevor remains (in this episode) with his current way to analyse what happens with formulas. And still while remaining with the equations doesn't give him the reason on why it would be a negative sign (he refers to it as "no reason") he doesn't engage in Rob's discussion of energy in a more conceptual (not quantitative) analysis.

Bridging Forces and Energy understanding
At the beginning of the video we observe how Rob can articulate what happens in terms of forces involved while lowering the ball at a constant speed. Then he try to go from the force story into the energy story. Since he knows there is a force opposing the movement, he tries to figure out how does that force affect the energy involved in the scenario. He relates the opposing force with thermal energy as something resisting. I found it interesting, but still not know where does this goes (since after that they conversation thread changed). Is thermal energy related as something opposing as a result of a friction force being translated/represented as thermal energy while going to the energy story?

Lack of responsiveness
One of my personal research interest is see how being responsive to each other can lead to a better understanding. In this case we observe Rob trying to engage in a discussion about how the energy is involved. Instead, we observe how Tracy do not respond to his thinking and starts a new idea without attending Rob's. At the end of this clip we observe the personal posture of Rob and Trevor but not necessarily a better understanding in the disciplinary content being discussed.

Getting to know Trevor
In E1 I-RISE scholar, Trevor has been such a particular character to discuss. He presents himself as a kind of expert, he often tend to teach during the discussion, he plays with his Rubik cube, etc. Kara and Abby has shown a high interest in study him in detail during the course, I think this episode would personally like them two to understand him better or having more documentation on his behavior. In both days I was recording the team of Trevor (not planned, just happened).

In the field notes we can observe he has not completely bought the idea of understanding energy (or science in general) without the use of formulas. For example, in the field note (E1_130809_Wed_AM):

9:31 am

Adam- kids change their thinking (SR)

Trevor- There are so many real world examples just showing the math

{KG- And Trevor is back to talking about the need of math to teach physics/energy.}

 …. look how much motion you are getting out of this little battery (SR)

Here we observe in this episode how he goes back to explaining the energy with the resources he already have formulas (instead of using the ones promoted in this PD), even when he can't completely explain the reasoning behind them. He saying to make a negative sign for no reason, just to make all the formulas work beautifully, indicates he has an opportunity for learning. His current resources can not explain fully the scenario analyzed ("no reason"), and still he is not engaging in the discussion of energy in a conceptual way. According to the field notes from Thursday morning, he seems to have troubles believing in constructivism (base of the PD strategies implemented). We have no video of that but I share the field note from it (E1_130808_Thu_AM):

{{Without headphones, I can hear the conversation going on at Table 3.  Trevor is insisting that constructivism is nonsense, basically.}} {{ Bummer that we don't have it taped. I wish we did.}} {{Me too.}}  {{Wow, this talk is so disparaging toward students.  "Yeah, it's common sense.  But your common sense is _wrong_." Laughs.}}{Well, we still have 7 more days to get him to open up a little...}

[Next episode of the saga: Forces vs Energy... (Afternoon ET 08-09 saga - part 2)]