Leaves in the Street (redux)

Leaves in the Street movie
(*I'm having trouble uploading the video, but will continue to try*)


full transcript follows:

Do leaves in the street have energy?

S1 = girl in black hoody
S2 = girl in purple hoody
S3 = boy in dark green military jacket
S4 = girl in green hoody
S5 = girl in blue shirt under black sweater, with headband
T = Teacher


1 S1: You're such a rebel.
2 ((students murmuring while writing))
3 S3: No- she wrote yes no.
4 S4: What? I'm just writing yes. All right. Leaves in street. I don't think so. Cuz it's
5 just the wind.
6 S2: Yeah. I don't think I don't think the leaves in the street have energy.
7 ((S1 sits up))
8 They have a type of energy but (.) ( )
9 S5: But is wind energy?
10 (.)
11 S2: Wind is energy.
12 S4: OH:: Should we write [it down?
13 S5: [Well they’re
14 S5: [ They're getting wind energy.
15 S3: [But it's not talking about the wind.
16 S2: It's just talking about the leaves in the street. The leaves- the leaves
17 in the street do they have energy.
18 (S4:) (No.)
19 S3: They are pushed by energy.=
20 S2: =They have ↑energy. But they do not have energy (.) like to move.
21 (1.2) ((S2 moves hand on table and taps))
22 S2: (Like) perpetual motion. You'd have to have wind to do that.
23 S5: True but are we (.) I mean (.) uh a: bus doesn't have perpetual motion.
24 S2: True. ((turns to S4))
25 (I’m just thinking like)
26 S5: None of these do.
27 S2: I'm just thinking like (.) they each
28 S4: =It’s just a yes no answer.
29 S2: (like like) The bus has some type of you know (that) and then you know
30 a bike (.) has its whee:ls. ((turns to S1))
31 ((S1 slight nod))
32 S2: you you move. (I’m thinking a leaf (.) you normally [don't
33 S1: [( ) a machine
34 S2: Yeah. yeah. Uh uh a leaf you don't really u::se it that much. You don't really
35 [(.) do::: much
36 S1: [(it doesn't like) do::::
37 S2: You know? It kinda si:::ts there until something mo:::ves it. But wind- well I
38 don't think wind (.) ha:::s energy. Well it has [( )
39 S5: [You can use wind
40 [to like po:wer stuff
41 S2: [It creates energy.
42 S5: It can be a source of energy. ((points with pencil))
43 S2: Yeah. Your wind (.) is like your foot (.) on a pedal.
44 S4: [( ) ((laughs))
45 S5: [Yeah. It's a source of energy. S:: [huh I mean the leaves have a=
46 S2: [So I don't know
47 S5: =source of energy.
48 S2: The leaves have a source of energy but they don't have like (.) energy to move
49 what they're talking about is motion. Is motion energy. And I don't think the
50 leaves have motion energy? [( )
51 S1: [But does it invo:::lve energy.=
52 S4: =You guys I think we should say yes no [because the leaves=
53 S1: [(It involves energy)
54 S4: =themselves don't have energy but the wind (is moving them). So it's a
55 (.) ((gesture))
56 ((S2 raises hand))
57 S1: ((turns to S5)) It invo:lves energy cuz of the wi:nd.
58 S2: But the leaves in the street- If it said (.) leaves moving I would say yes. It says
59 leaves in the street. You could have [leaves in the street without wind.
60 S5: [But the leaves we::re mov[ing.
61 S4: [moving.
62 S2: But they were moving because of the w[ind.
63 S4: [wind.
64 S2: I'm saying if you [ha:d (.) you're like
65 S5: [Cuz that was their source of energy
66 S2: But if you had=
67 S3: =Wind.
68 S1: [But it says does it invo::lve energy
69 S2: [Leaves on the street without without ((looks at S1))
70 But what if you had leaves on the street without the w[ind ( )=
71 S4: [wind
72 S2: =moving. I just think you need both pie:ces=
73 S5: =True. But I mean what like a bus without gasoline wouldn't move either.
74 S2: [Oh true
75 S5: [And like a bicycle without peda[ls (.) uh a pedaler wouldn't move either. So
76 S4: [pedals ((laughs)). I'm trying to like uh say
77 things at the same time ((laughs))
78 S2: I don't know I don't- I just don't know (I just think that) a [lea::f wouldn't (.)=
79 S1: [It's (.) it's like it is
80 but it ( )
81 S2: but I feel but I feel like in my mind I feel like if its (.) it's ↑energy (.) it's it’s
82 involved in (the) type of energy
83 (1.0) ((S5 delayed nod))
84 S2: It's involved in a type of energy [(jus like)
85 S5: [(is that) meaning
86 S2: Well I'd say okay I'm gonna put yes slash no:? (Yes) it's involved in a type
87 of energy=
88 S4: =That's what I was saying the whole time but no one was listening

Yesterday I had the chance to sit in E2 and hear an extended version of Rachel's AAPT talk on "intuitive ontologies" for understanding energy. I hadn't read Rachel, Hunter and Sam's paper (R. E. Scherr, H. G. Close, and S. B. McKagan, "Intuitive Ontologies for Energy in Physics," ) but I HAD watched this video many times while preparing my EPSRI application. Rachel said very little before showing the movie, but she did present the concept of "intuitive ontologies" and she also mentioned her belief in students' ease with flexible use of different metaphors for energy. Then she showed the movie.

The first time(s) I watched Leaves, I focused on the social construction of knowledge. I was interested in S2's interactions with other students at the table; her thinking process was getting a lot of attention, both positively from her and from S5 and S1, and negatively from S4, and I was curious to see how all the engagements were involved in the creation of a group understanding energy descriptions. But this time, with Rachel's prompts, I focused instead on the ontologies S2, S5 and the other students were employing in order to better understand the energy scenario. I found this line of focus MUCH richer--both more explanatory and more supportive of the actual cognitive process the students were undergoing.

One thing that puzzled me on first viewings was the way in which S2 moves from saying (very definitely) "wind is energy"(L 11) to saying seconds later "I don't think wind haaas energy. Well it has [you can use wind.." (L 38). Then in L45 S5 says "Yeah. It's a source of energy". This shift from wind is energy, doesn't have energy, is a source of energy really confused me. I noted the shifts but couldn't track what had produced them, and my impression of S2's cognitive process was inchoate. What thrilled me about the ontological/intuitive metaphor approach Rachel introduced is that it instantly made sense of this progression.

As I watched this episode again after Rachel's intro, I noticed a distinct shift from the use of the substance metaphor "the leaves have energy" (L2) to the stimulus metaphor, in which energy is a stimulus to motion "the leaves in the street...are pushed by energy" (L16-19) to a metaphor of energy as fuel wind is "a source of energy"(L2).

The notion of fuel as energy metaphor is immediately interesting because of the way it supports the 2nd law of thermodynamics. Some energy is 'usable', 'consumable' like fuel, and other energy is thermalized, diffused, essentially spent. It also supports our sociopolitical discussions around energy. The kind of energy we are concerned to conserve, the kind that doesn't automatically conserve itself, is of this 'usable' fuel-like variety. Physicists traditionally operate on ideal systems in which second law realities can be separated conceptually from energy accounting, but it makes sense that students, embedded in the real world, are drawn to form concepts of energy that account for the relevant features of energy systems in the real, non-ideal world.

It's intriguing (from this 2nd law perspective) that perpetual motion crops up as the group negotiates a switch from energy-as-stimulus-to-motion to energy-as-fuel. Here's an excerpt:

16 S2: It's just talking about the leaves in the street. The leaves- the leaves
17 in the street do they have energy.
18 (S4:) (No.)
19 S3: They are pushed by energy.=
20 S2: =They have ↑energy. But they do not have energy (.) like to move.
21 (1.2) ((S2 moves hand on table and taps))
22 S2: (Like) perpetual motion. You'd have to have wind to do that.
23 S5: True but are we (.) I mean (.) uh a: bus doesn't have perpetual motion.

at L 22, S2 is searching for an energy ontology that will allow her to express second law realities. When S5 protests that a bus doesn't have a perpetual motion either, S2 agrees and then tries to formulate the new metaphor more clearly:

24 S2: True. ((turns to S4))
25 (I’m just thinking like)
..
29 S2: (like like) The bus has some type of you know (that) and then you know
30 a bike (.) has its whee:ls. ((turns to S1))
31 ((S1 slight nod))
32 S2: you you move. (I’m thinking a leaf (.) you normally [don't
33 S1: [( ) a machine
34 S2: Yeah. yeah. Uh uh a leaf you don't really u::se it that much. You don't really
35 [(.) do::: much
36 S1: [(it doesn't like) do::::

The metaphor she's searching for (energy as fuel analog) incorporates a notion of usability. S2 emphasizes the consumption of this usability with the long-drawn out "u::se" and "do:::"--the duration of the vowel suggests a 'burn phase' as something (something like fuel) is u:::::sed up, consumed. Having now shifted (through a noticeable cognitive reach for metaphor--"I'm just thinking like...like like..the bus has some type of you know..") to the metaphor of energy as fuel, it now makes perfect sense for S2 to declare that wind is NOT energy in this sense:

37 S2: You know? It kinda si:::ts there until something mo:::ves it. But wind- well I
38 don't think wind (.) ha:::s energy.

Wind doesn't seem initially burnable, usable. Perhaps because it does not feel organized for use, the way that fuel does? But then she remembers and is reminded by S5 that you can use wind to power stuff, to "create energy" so she agrees in L45 that wind is, in fact, "a source of energy".

Again, what I find nothing less than thrilling about detailed tracking of the way these metaphorical shifts are negotiated is that the process reveals that students are already employing their intuitive ontologies in an extremely logical and consistent manner. The fluid shifting can make the logic difficult to follow unless video recording is employed, and the entire negotiation wouldn't happen audibly unless a small group were employed in the cognitive exercise. But once those two things are in place, it's easy to see the way in which students are engaged in sophisticated virtual testing and refinement of competing ontologies.