Interpretive Flexibility
This episode illustrates the interpretive flexibility of the microworld, its objects and events, and the expressions used to describe it. Interpretive flexibility became an important resource in the evolution of the students' talk.
Data.[i]
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55. G: Oh yeah the big arrow 's time, 'K [É] the big arrow 's time. 56. R: OK, we'll make it shorter. 57. L: So then the little arrow is direction. [É] |
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58. G: Yeah the big arrow is direction. No I mean the big arrow is velocity= |
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59. L: =No, time= |
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60. R: =No, it's time but it also directs, though. |
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61. L: Yeah and then the little arrow, no the little, isn't the little arrow. [ÉÉ] |
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62. R: We don't know yet. What did I do? |
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63. G: So the little arrow, the little arrow always stays straight whatever we do. |
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64. R: You can turn it [Shows how [force] can be turned] 65. L: Yeah you can turn it |
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66. G: Yeah but when we're doing it, it goes in that straight direction anyways (Following earlier displayed trajectory of object) |
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67 L: Yeah but I think that little arrow might also be direction [É] 68 G: But the big arrow is also direction= 69 L: =I know, [É] can we look, can we now move the little arrow? |
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Conversational action.
Gaalen picked up on Linda's earlier description of [force] as time (55).[ii] Randy suggested to test this idea by running a new experiment with a smaller [force] (56). Continuing with the task of finding labels for the vectors, Linda suggested that [velocity] represented direction (57). However, Gaalen made clear that his meaning of the two arrows was different; he first used "direction" as a label for [force], but then changed it to "velocity." In this, he disagreed with Linda who reiterated the label "time" for [force]. Randy modified the earlier shared assumption claiming that [force] is "time but also directs" because he perceived it as the agent which changed length and direction of [velocity] (60). This left Linda confused, and Randy, rather than risking yet another label for [force] suggested that they still did not know. Gaalen shifted to a new description and proposed that the "little arrow" always stayed the same; he held his pencil parallel to [velocity] to indicate direction (63) thus suggesting that his referent was [velocity]. However, in the present context, "the little arrow" was more likely about [force] because Randy and Linda considered the possibility of changing the direction of "it," while Randy demonstrated how to change the direction of [force] by "grabbing" [force] at its tail and pivoting it around its tip (64-65). Gaalen viewed his response as a contrast ("Yeah, but when we are doing it, it goes in that straight direction anyways") for he accompanied his statement by a gesture in which the pencil showed the change in the direction of [velocity], while his hand described the trajectory of the object (66). Here, he clearly demonstrated a change in the direction of [velocity] suggesting that it was [force] and not [velocity] which stayed constant. While this constituted a contradiction to his earlier statement, it was in agreement with the position of Linda and Gaalen. Linda then proposed that "the little arrow" indicated direction (67), but Gaalen countered that "the big arrow is also direction" (68). Linda used "the little arrow" to index [velocity]. This is consistent with her statement in (69), GLR's action of changing the direction of [velocity], and the shared meaning prior to the present excerpt; but this was inconsistent with the use of the same label in (64-65). Gaalen in turn used "the big arrow" to label [force], consistent with Linda's label, but inconsistent with his prior use of a different label for the same referent.
Analysis.
In this episode, the meaning of [force] changed and the referents "little arrow" and "big arrow" alternated repeatedly. For example, [force] was thought to be time, direction, velocity, and something that "directs" motion. Similarly, "little arrow" indexed [velocity] (57), [force] (63-65), and again [velocity] (67, 69). This suggests an interpretive flexibility of the objects and events in the microworld and of the labels used by the students. In their conversations, the referents for specific concepts and the labels for specific objects changed, implying a change in the meaning relationships of their discourse. This interpretive flexibility is apparent from Table 1 which lists the different labels GLR used in the course of their interaction (for illustrative purposes, GLR's list is contrasted with that of another group which included the highest achieving student in the course).
insert table 1 about here
In this part of the conversation, the students converged on "direction" as a critical descriptor of both [velocity] and [force]. This consensus emerged in spite of the changing meaning of objects, events, and the terms to describe them. Their shared science talk emerged as students contributed different descriptions. For Linda, "the little arrow" showed the direction of the object's motion (57, 67), while Gaalen and Randy suggested that the "big arrow" also contributed to the direction of the object's motion (60, 68). This episode illustrates a shift in conversation (from the discussion of [force] as time) and a corresponding change in the experiments students decided to conduct; in these new experiments they changed the direction of [force] and [velocity] both with respect to the coordinate system and relative to each other.
Hand in hand with the interpretive flexibility frequently went the occasioned (situation-dependent) character of students' investigations. They explored the microworld phenomena in what appeared to be an ineffective search. Most of their experiments developed out of specific situations on the screen and in conversation rather than some structured approach. For example, while trying to increase [force], a student disconnected it from the circular object which occasioned a test of motion without [force]. From a teacher's and analyst's perspective, students explored critical cases in undirected ways and they varied parameters in haphazard ways. Any such system can be efficiently explored by varying one parameter at a time, based on extreme cases, rather than committing to an exhaustive trial and error search. Here, a physicist might explore the cases of both vectors lined up in the same, opposite, and orthogonal orientations.
Claims
From an interactionist and pragmatic viewpoint, talk is a form of action. In this view, students' learning is expressed in the modification of existing language games. Through such modifications, current ways of talking are situationally adjusted to optimize the performance of descriptions and explanations for the task at hand. Because students interpret objects, events, and the labels in a flexible manner, the latter have ambiguous ontologies; the intrinsic nature of phenomena is not fixed, but shifts as students try to adapt their science talk to the situation at hand. Some may consider this interpretive flexibility a barrier to learning. However, it was considered here an important resource in the students' learning. Interpretive flexibility allowed students' meanings to change so that they came to share meanings within a group.
While seemingly random explorations appear to be "inefficient" learning strategies (because they are unsystematic), the studentsÕ explorations look more positive when compared to scientists' learning in unfamiliar domains. Recent ethnographic studies of scientific laboratories and scientists' self-reports show that scientists who work on the "cutting edge" often vary experimental conditions or models unsystematically. In the search for new superconducting materials, physicists randomly tried new compositions of materials or variations in the procedures for baking their new mixtures (Felt & Novotny, 1992); geneticists pursued "all sorts of leads" before they picked from their records those data that told a rational story (Suzuki, 1989); and biochemists decided to do experiments because they had pieces of equipment developed for other projects rather than for epistemic reasons (Knorr-Cetina, 1981).