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In this paper, we analyze the relation between particular, contingent, and general aspects of a school science activity and show how they are intertwined in nontrivial ways as students give explanations for how a real galvanic cell works during conversations with a researcher. The conversations were examined by using practical epistemology analysis, which made it possible to follow students’ meaning making in detail. The analysis revealed interactions between generic explanations of electrochemistry and the distinctions and correlations that were connected to particulars and contingencies of the galvanic cell. Consequences of these interactions amounted to becoming reminded of knowledge one had come across before, being able to connect distinctions of particular features of the cell to generalized chemical explanations, and realizing which aspects may be excluded from the account. The results indicate that learning in science needs to be approached more as a contingent process than as something that progresses along one particular dimension. They show how students appropriate the sociocultural tools of science and how they situate what they learn in both the particular features of the activity and in the relevant science. Hence, there is a need for more inclusive accounts of how students progress toward increased competency in science.


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In this study, we address the question of what kind of support students need to progress toward increased competency in science in secondary school. Trite as this subject may seem after more than 50 years of science education research, important review articles as well as recurring keynote themes at science education conferences testify to the difficulties that we as a field still face when it comes to converting research results into working suggestions for teaching (see, e.g., Scott, Asoko, & Leach, 2007). On the basis of our previous research (reviewed below) as well as on the research of others working within a sociocultural tradition, we argue that this inefficiency on the part of the science education community is a result of the field still adhering to a conceptual-change account of learning science and that this is a too limited and inadequate way of approaching what is involved when students progress through the school science curriculum.

The problem with this conceptual-change account is its heavy focus on students acquiring a correct understanding of the scientific ideas of particular science topics (Anderson, 2007), whereas other potentially important science content is dealt with merely in terms of contextual factors influencing the conceptual-change process (see, e,g,, Treagust & Duit, 2008). One sign of this, although by no means the only one, is the emerging field of learning progressions in science, in which descriptions of student learning are limited mainly to hypotheses of the order in which they acquire the generalized concepts and ideas of science (see Corcoran, Mosher, & Rogat, 2009, for a comprehensive review of this field). Yet, several studies within the science education field demonstrate that students need to learn to situate generalized conceptual explanations within the purposes and norms of school science activity (Kelly, Brown, & Crawford, 2000; Lidar, Lundqvist, & Östman, 2006; Schoultz, Säljö, & Wyndhamn, 2001a; Säljö & Bergqvist, 1993; Wickman, 2006). Indeed, the focus on learning generalized conceptions and ideas has been challenged even within the conceptual-change tradition. For instance, diSessa, Gillespie, and Esterly (2004) treated slight variations in context during clinical interviews not as factors needing to be controlled for, but as constitutive elements of student conceptual change. However, as diSessa (2006) pointed out, in a review of the history of conceptual-change research, such efforts to reconcile the conceptual-change account with the increasing appreciation of the situated nature of learning (e.g., diSessa & Sherin, 1998; Kelly & Green, 1998) have generally been treated as minority opinions or even been ignored altogether.

Unfortunately, the notion of situated learning is sometimes taken to mean a certain kind of learning tied to particular situations, as opposed to acquiring knowledge, which can be generalized across cases. Perhaps this is the reason why even some socioculturally influenced authors within science education (see, for instance, Scott et al., 2007) tend to draw a line between learning to participate in activities involving science content on the one hand and acquiring the conceptual resources for explaining natural phenomena on the other (cf., Sfard, 1998). On the other hand, if students’ reasoning in science is closely tied to their actions for coping with the particular problems of a practical activity, as has been demonstrated by several authors (Goodwin, 1993; Hamza & Wickman, 2009; Hwang & Roth, 2007; Jiménez-Aleixandre & Reigosa, 2006; Lindwall & Lymer, 2008), then maps of student learning in science that focus only on its big ideas while leaving out these additional aspects will most likely be too simplified to be useful as guides for teaching.

What we need, we believe, is neither more detailed nor more generalized accounts of students’ ideas of science, but more inclusive ones, taking into consideration the wider range of aspects that have been shown to play significant parts in how students progress toward increased competency in science. In this study, we present detailed analyses of how some of these aspects interact to further the learning of certain science content during conversations between a researcher and individual students around a real galvanic cell. Before that, however, we present in detail the particular studies that form the immediate backdrop to the present study.


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During the past two decades, there have been successful efforts in science education research to study learning as action, rather than thinking, and analyze learning as part of whole activities (Greeno, 2006; Kelly, 2004; Wickman, 2006). Today, science learning in school can be productively studied as a process of becoming increasingly competent at participating in different discursive practices in which scientific language is used for particular purposes (Lemke, 1990; Sensevy, Tiberghien, Santini, Laube, & Griggs, 2008; Wells, 2008; Wickman & Östman, 2002). Here we focus specifically on a limited part of such competency, namely handling the purpose of coping with a real phenomenon (a real galvanic cell) through providing situated explanations for how it works.

This discursive move, as it were, has opened up new possibilities for studying a wide range of aspects that may play significant roles in how students’ learning progresses through a school science activity (Greeno, 1997; Kelly, 2004; Wickman & Ligozat, 2010). In particular, the approach known as practical epistemology analysis (PEA) (Wickman, 2004; Wickman & Östman, 2002) has made it possible to analyze the interplay between what and how students learn in the course of a school science activity. PEA is built primarily on the ideas of Dewey and the later Wittgenstein but also shows close kinship with socioculturally oriented approaches (e.g., Lemke, 1990; Wertsch, 1991). It should not be confused with the idea of students’ personal “practical epistemologies,” which was later introduced by Sandoval (2005). Unlike Sandoval's purely cognitive concept, PEA takes its departure from an antirepresentational account of knowledge from Rorty's (1991) perspective. It was developed as a theoretical mechanism of learning on a discursive level, thereby enabling analyses of how learning proceeds in situ in the science classroom (Wickman, 2004; Wickman & Östman, 2002).

Because PEA operationalizes learning in terms of participants establishing continuity between various parts of an activity during discourse, it has been used successfully in our earlier research to describe learning in science in broader terms than what can be observed in the commonly studied cognitive dimension alone. On the basis of detailed analyses of what students, ranging from primary to university level, are actually doing in the classroom, we have been able to develop this more inclusive account of science learning in detail concerning also its normative and aesthetic dimensions. Thus, we now know that as students progress through a science learning activity they do so by establishing important links, continuity in pragmatist terms (Dewey, 1938/1996), between cognitive, normative, and aesthetic dimensions of the activity (Jakobson & Wickman, 2007a, 2007b; Lundegård & Wickman, 2007; Wickman, 2006). Without taking these “other than cognitive” aspects into account, the descriptions of what students are struggling with when they learn science become inadequate. Thus, supporting students through a school science activity may equally involve helping them to deal with normative or aesthetic dimensions rather than just purely cognitive ones. Indeed, this claim has been verified in some naturalistic studies of teacher action in the secondary science classroom (Lidar et al., 2006; Lindwall & Lymer, 2008).

In line with these results, but more related to the present study, we set out to empirically investigate to what extent the misconceptions of generalized conceptual and propositional explanations of electrochemistry (comprehensively laid out by Garnett & Treagust, 1992a, 1992b) interfered with upper secondary students’ reasoning, while they gave explanations of how a real galvanic cell in the school laboratory worked. Numerous such misconceptions have been identified within this topic (Garnett & Treagust, 1992a, 1992b; Sanger & Greenbowe, 1997), and their alleged influence on student reasoning may be said to constitute the very essence of a conceptual-change account of learning in science. Because our analysis focused on all of the discursive transactions occurring in the activity, rather than on the conceptual-change dimensions of students’ understanding alone, we were able to describe some aspects of the activity as a whole, which afforded or constrained the development of their reasoning on the real galvanic cell during the lesson.

In the first study (Hamza & Wickman, 2008), we showed that students’ ability to handle the particulars and contingencies that emerged in encounters with a real galvanic cell was at least as important for furthering the activity as was their ability to use the more generalized conceptual and propositional explanations, which were stipulated by Garnett and Treagust (1992b) as being essential for explaining how a galvanic cells works. Our results indicate that the impact of misconceptions on students’ learning of electrochemistry in the classroom has been unduly postulated from how these misconceptions worked in entirely different situations, mostly interviews or paper-and-pencil tests. We concluded that the part played by these and similar conceptual-change dimensions of students’ understanding of a science topic has to be understood in relation to a number of other aspects of the activity. Similar results have also been reached by other authors in the field (Hwang & Roth, 2007; Jiménez-Aleixandre & Reigosa, 2006; Kelly & Green, 1998; Schoultz et al., 2001b).

We may generalize these findings in the following way: As soon as the generalized conceptual and propositional explanations of a science topic are set in motion, such as through interactions with a real galvanic cell, it is insufficient to explain students’ difficulties when explaining a particular scientific phenomenon by only referring to their understanding of these generalized scientific ideas. Instead, we need to understand how they learn to act in whole situations, including encounters with generalized explanations, possible misconceptions of these explanations, and other previous experiences, as well as with all the particulars and contingencies of real practice. Consequently, in the second study (Hamza & Wickman, 2009), we described and categorized some of the other things that students needed to learn to cope with the particulars and contingencies of a real galvanic cell, apart from the generalized conceptual and propositional explanations outlined by Garnett and Treagust (1992b). We showed that the students also needed to engage with issues to do with distinguishing, naming, and recognizing particular features in the galvanic cell, as well as with correlations and causal relationships pertaining to the cell (Hamza & Wickman, 2009). Here, then, the fault line did not necessarily go between cognitive and noncognitive dimensions of a learning experience, but also between different aspects of learning along the cognitive dimension, for instance actually making certain distinctions or noticing correlations in addition to using generalized scientific ideas.1 Nevertheless, it was not only the cognitive aspects of learning to make distinctions and establish correlations, which were important for students’ possibilities of coping with their galvanic cell. Also vital were the normative aspects of learning when these distinctions and correlations constitute relevant parts in relation to the purpose of the activity.

For example, the students engaged in issues of naming the constituents of the galvanic cell by making increasingly finer distinctions between metals and solutions. Moreover, they needed to learn how to recognize and name the products and processes of the galvanic cell, when these distinctions were relevant to include in their explanations, and also when they were not. Recognizing and naming the layers formed on the electrodes, for instance, was important for students’ ability to give an explanation of how their particular galvanic cell could produce current, as was deciding that the distinction between metals and metal ions was relevant for coping with the function of the half cells. According to Schwab (1978), from whom we borrowed the central terms for producing a systematics for our findings, the need to develop a particular ontology is an integral part of any scientific activity. He referred to this aspect of scientific practice, in which relevant aspects of interest in the field are distinguished and named, as taxonomic science. We refer to actions in which student and researcher jointly distinguish and name constituents of, and processes in, the galvanic cell during the conversation as taxonomic investigations.

We also showed that students needed to engage in various issues of measurements of correlations and tests of causal relationships pertaining to their cell. For instance, readings of negative voltage or problems of connecting a light-emitting diode (LED) to the right terminals became important issues in the students’ explanations of their real galvanic cell. Moreover, some students engaged in reasoning concerning correlations between voltage and time or between the time for taking out an electrode and interruption of the current, as well as whether these correlations were relevant for the purpose of explaining how their galvanic cell worked. Students thereby extended their use of terms such as voltage to issues of, for example, the meaning of negative voltage and how to recognize whether the voltage of their galvanic cell increased or decreased. Schwab (1978) labeled the variety of scientific knowledge in which correlations and causal relationships are measured and described as measurement science. Here, we refer to such actions during the conversation as correlational investigations.

Finally, Schwab (1978) assigned efforts to produce relations between known facts, systematize them, and eventually construct theories to a third variety of scientific knowledge, which he called relational science. General conceptual and propositional explanations, for example those identified by Garnett and Treagust (1992b), are one example of this scientific practice. Engaging in investigations into such generic explanations constitutes a legitimate focus for a student who tries to give an explanation of a particular phenomenon in science class. It dominates research into students’ learning in science (cf., Scott et al., 2007) as well as school science practice (Roberts, 1994).

Thus, according to our two previous studies (Hamza & Wickman, 2008, 2009), for a student to be able to cope adequately with the real galvanic cell in front of her, it is as important to come to terms with taxonomic and correlational issues pertaining to the cell as it is to come to terms with the relevant conceptual and propositional explanations. However, no one expects students to progress through the school science curriculum on their own. A more knowledgeable person, usually a teacher, is required to support students as they struggle to come to terms with the scientific point of view. The role of dialogue as a motor for learning science is well established (Mercer, 2000, 2008; Mortimer & Scott, 2003). Moreover, the strategies that teachers use to create opportunities for learning by engaging students in the use of scientific language for different purposes have been carefully described. In particular, an extensive body of research on scaffolding has described a variety of different ways in which teachers provide temporary support for students as they struggle to solve a problem (Chin, 2007; Puntambekar & Hubscher, 2005; Ritchie, 1998, 1999; Sharpe, 2006; van Geert & Steenbeek, 2005; Wood, Bruner, & Ross, 1976). Examples of such scaffolding include simplifying the task, marking relevant features of the task, and using questions, cues, or analogies to support the student's reasoning. In line with this extensive body of knowledge of the importance of interaction with a more knowledgeable person, we therefore staged a number of conversations between the first author (an experienced science teacher) and one student at a time. Through the conversations, we were able to deliberately introduce investigations not only into matters concerning generalized explanations of electrochemistry but also taxonomic or correlational ones in line with our two previous studies. Note that these taxonomic and correlational investigations also included normative aspects of whether certain distinctions and correlations were important or not for coping with the purpose of the activity.

Interactions with a teacher through various scaffolds and prompts are generally seen as temporary support (Puntambekar & Hubscher, 2005). The aim is to eventually remove the support, as the student successively learns to manage the task on his or her own. However, this is not the case with the taxonomic and correlational investigations that the researcher introduced into the conversations in the present study. Rather, these investigations were intended to promote learning, or at least reminiscence, of additional content hypothesized to be of importance for the progression of the student's explanation of the real galvanic cell. There is no intention here of this additional content being only temporary to support the learning of the generalized concepts and ideas. Instead, the idea is that learning to explain a real galvanic cell also requires this additional content.

Our previous studies thus constitute an effort at producing a tentative systematics for how students learn to deal with the particulars and contingencies of actual practices as part of studying how they progress toward increased competency in science. In the present study, we take this effort one step further by analyzing how students’ learning progresses, as they are also actively encouraged to deal with these aspects of school science activity. In that way, the present study constitutes another step for establishing how aspects other than those emphasized by the conceptual-change tradition may contribute to supporting students’ progression toward increased competency in science. Specifically, we ask how investigations into the particulars and contingencies of a real galvanic cell interact with each other and with the generalized explanations of electrochemistry, as students together with a researcher develop their explanations for how the real galvanic cell in front of them works. Our idea is that if a researcher can help a student to make sense in this way, it should be of use to teachers too.


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Conversations With Students

We audio-recorded eight conversations between the first author and one student at a time (there were three students from the science program and five from the technical program). The first author has 10 years of experience as an upper secondary teacher in biology and chemistry. Each conversation lasted between 40 and 60 minutes. The audio recordings were transcribed verbatim. We conducted the conversations in two municipal Swedish upper secondary schools in two consecutive school years between 2006 and 2008. The conversations took place at the end of the general chemistry course (labeled Chemistry A). We presented our research interest and the specific activity to the teachers about 2 months before the conversations took place. Both teachers chose to incorporate the activity at the end of the course. In that way, the conversations would constitute an opportunity for participating students to review some of the electrochemistry before a final test covering the entire chemistry course, which both teachers were going to administer. The students had come into contact with electrochemistry in two units during the course, one concerning redox reactions and another one concerning energy. They had also done laboratory work involving redox reactions as well as galvanic and electrolytic cells. Both teachers considered that the activity fit well into the curriculum and presented the students with an appropriate degree of difficulty.

The students volunteered on the premises that (a) we wanted to test some new ideas about how a teacher can support students’ reasoning in electrochemistry and (b) the conversation would be an opportunity for students to learn about electrochemistry. We told the students that their regular teacher would not get access to the recordings and that we would not tell the teacher about the outcomes of the conversation. The students were informed that they would remain anonymous. We also made it clear that, even if a student had volunteered, he or she should feel free to leave the conversation at any time. The conversations proceeded in a comfortable mood, and all students followed through with the activity.

Each student was given a written lab sheet in which the task was to construct a working galvanic cell and try to explain how and why the cell in front of him or her can produce electric current. The lab sheet contained detailed instructions about how to assemble the galvanic cell and how to connect it to an electric motor and a LED. The instructions specifically asked the student to discuss and try to explain (a) how a current can occur in the cell, (b) which chemical reactions take place, and (c) what role the glass filter at the bottom of the U-tube has. Hence, the general purpose of the conversation concerned relational science and how to develop the general concepts that were needed to explain the working of the cell. Thus, progression toward increased competency in science is operationalized as managing to cope with this limited purpose of explaining how a real galvanic cell works and do this more successfully as a result of a taxonomic or correlational investigation.

Figure 1 illustrates the essential features of the setup. However, no such picture was provided in the instructions.


Figure 1. A schematic representation of the electrochemical cell used in the conversations, and what could be observed to happen (the laboratory instructions provided to the students did not contain any such representation, however). It was possible to observe that the magnesium electrode turned dull (as it oxidized) and that a red layer (of copper) formed on the copper electrode. On the magnesium side, a bluish precipitation (of magnesium/copper hydroxide) and bubbles (of hydrogen gas) formed. Some leakage of copper sulfate solution through the glass filter could be observed. The electric motor could be connected either way, whereas the LED had to be connected to the right terminals. The voltmeter gave a positive or negative reading of voltage depending on which terminals it was connected to.

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After the student had read through the instructions, the researcher asked him or her to continuously talk about what s/he was doing during the activity. He also explicitly invited the student to ask for help and guidance whenever needed. Thus, the conversations conducted in this study should not be considered as interviews, since the researcher made it clear that he was not interested in evaluating the student's understanding. Instead, he stressed that his immediate role was to assist the student in his or her reasoning concerning the galvanic cell. In general, the researcher intervened either in response to a request for help from the student or when he decided that the student needed assistance to proceed with the activity. The ground rule determining the interventions was that they, when reasonable, should initiate a taxonomic or correlational investigation to support the student's explanation of the cell. Of course, the researcher also gave more general support in the form of clarifications, questions, and prompts. As pointed out above, however, the taxonomic and correlational investigations initiated by the researcher constituted clearly discernible and qualitatively different kinds of support to this more general provision of different scaffolds. Thus, the researcher acted as an ordinary science teacher interacting with a single student, except that certain interventions systematically directed the student's attention specifically toward taxonomic and correlational issues pertaining to particular and contingent aspects of the real galvanic cell in front of them.

Specifically, the taxonomic investigations that were introduced had to do with distinguishing and naming the constituents of the cell as well as some of the products of the reactions. The initial actions taken to direct a student's attention toward these issues, in encounters with the galvanic cell, were often to ask the student to describe “what we have” or “what we see” in the cell. Concerning the correlational investigations, we specifically focused on two aspects. The most common one concerned how the placement of leads correlated with the function of the LED or with the reading on the voltmeter. In a couple of cases, the researcher asked the student to investigate what happened if one of the electrodes was pulled out of the U-tube. In the analysis, taxonomic and correlational investigations were operationally recognized through such gaps and relations being established. The researcher actively initiated taxonomic or correlational investigations on 44 occasions in the eight conversations conducted.

Analytic Approach

In our analyses of the conversations, we first identified different kinds of investigations (i.e., taxonomic and correlational ones as well as investigations into generalized conceptual and propositional explanations) in line with the results from our previous studies (Hamza & Wickman, 2008, 2009). We then analyzed how these investigations interacted to further the students’ explanation of the actual galvanic cell in front of them. To do this, we used PEA (Wickman & Östman, 2002), which is standard methodology for analyzing how students’ learning progresses through an activity (Kelly, McDonald, & Wickman, 2012). PEA was developed to describe how local discourses change on a moment-by-moment basis and how people increasingly become participants in new practices (Wickman & Östman, 2002). It amounts to a detailed account of the processes by which people learn to use words and actions to accomplish new things for particular purposes in an activity (Wickman, 2004). PEA is based on a discursive understanding of learning that is well suited to analyze how different actions in an activity interact to further the activity. It therefore fitted our purpose of analyzing how different kinds of investigations, as certain actions during the activity are labeled here, were made continuous in the conversations between the researcher and individual students, and how this continuity helped to further the purpose of explaining how the real galvanic cell worked. This continuity between distinctions, correlations, and generalized explanations is represented in graphic form in Figures 2-4.


Figure 2. The progression of Dave's reasoning (Excerpt 1) through a part of the conversation, showing how continuity was established between the taxonomic investigation and the main purpose of the activity. Indicated are the main gaps noticed in the course of the conversation, and the instances when these are not successfully filled with relations (“stop”) and therefore linger (broken arrows) as the conversation takes on another direction, i.e., a new gap is noticed. Filled arrows indicate the flow of the conversation, which may be followed chronologically through the references to particular turns in the excerpts. The flow is separated into actions having to do with giving the situated explanation of how the cell works, i.e., the main purpose of the activity, and actions concerning investigations into issues of taxonomies, correlations, and generalized conceptual and propositional explanations, respectively.

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Figure 3. The progression of Michael's reasoning (Excerpt 2) through a part of the conversation, showing how continuity was established between the taxonomic investigations and the main purpose of the activity. Indicated are the main gaps noticed in the course of the conversation, and the instances when these are not successfully filled with relations (“stop”) and therefore linger (broken arrows) as the conversation takes on another direction, i.e., a new gap is noticed. Filled arrows indicate the flow of the conversation, which may be followed chronologically through the references to particular turns in the excerpts. The flow is separated into actions having to do with giving the situated explanation of how the cell works, i.e., the main purpose of the activity, andactions concerning investigations into issues of taxonomies, correlations, and generalized conceptual and propositional explanations, respectively.

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Figure 4. The progression of Cassandra's reasoning (Excerpt 3) through a part of the conversation, showing how continuity was established between the taxonomic and correlational investigation and the main purpose of the activity. Indicated are the main gaps noticed in the course of the conversation, and the instances when these are not successfully filled with relations (“stop”) and therefore linger (broken arrows) as the conversation takes on another direction, i.e., a new gap is noticed. Filled arrows indicate the flow of the conversation, which may be followed chronologically through the references to particular turns in the excerpts. The flow is separated into actions having to do with giving the situated explanation of how the cell works, i.e., the main purpose of the activity, and actions concerning investigations into issues of taxonomies, correlations, and generalized conceptual and propositional explanations, respectively.

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PEA recognizes that, during a learning activity, students continuously move from one situation to the next. Each situation contains at least something which is new, if only because this particular situation has, by necessity, never occurred before. Consequently, there are certain things that need to be dealt with in order for the participants to be able to go on with the activity. This is operationalized as students noticing gaps in encounters with what occurs in the activity. Encounters are descriptions of what can be seen to meet or interact in talk and action in an activity. They occur between participants (e.g., a teacher saying something to a student) as well as between participants and the physical world (e.g., a galvanic cell). Also, operationally, gaps are filled by taking recourse to words or actions already known in the sense that they are not questioned by the participants and can be said to stand fast in the specific moment. These words and actions work as temporary points of departure for construing new relations to deal with a situation. Thus, operationally, students can only move from one situation to the next by filling the concomitant gaps with relations to words or actions that they already know how to use in other situations. A gap that is not filled with relations is said to linger and is seen through the activity coming to a halt or, more commonly, through taking on a new direction.

The qualifier “operationally” implies that noticing gaps in encounters and moving forward by construing relations to what already stands fast is not a theory about human action. Rather, by definition, the fact that participants can be observed to go on with an activity is described in terms of their filling gaps with relations to what stands fast. Thus, the four concepts of PEA are strictly analytical. They do not constitute entities that the researcher has to locate and identify in student discourse. For instance, a gap is operationalized through the participants expressing a need for a relation, either by merely establishing a relation (implicit gap) or by asking a question (explicit gap). A relation, in turn, is operationalized as talk or action that occurs during the activity, where relationships are established between acts, objects, or events. The sentence “this solution is blue” can thus be redescribed as two relations being established, one between “this” and “solution” and another one between “solution” and “blue.” Alternatively, it may be redescribed as one relation, “this solution—blue.” It all depends on the purpose of the analysis, not on any assumption of what the students were “really” up to by formulating this particular sentence. The corresponding gap may be represented through the implicit question “what color is this solution?” (Lundegård & Wickman, 2007). Again, this does not mean that the participants ever posed the question itself, nor that the color of the solution was considered a problem in the first place. But the relations were obviously established as part of continuing the activity.

Because the four concepts are not considered to be entities that are present in student discourse, but a way of describing how discourse is progressing according to purpose, there is no point in asking, for instance, whether the researcher has missed some gaps that the interlocutors have not expressed. Unlike Sandoval's (2005) homonymous concept, then, in PEA there is no sense in going beyond the activity to “uncover[ing] students’ practical epistemological ideas” as being the underlying cause of their actions (Sandoval, 2005, pp. 649–650). In PEA, the practical epistemologies are the habits of action that the participants use, overtly and in the moment, to cope with reality in relation to purpose (Wickman, 2004). The theoretical mechanism described above is a heuristic for carrying out this analysis of the ongoing practices in a science classroom.

Thus, PEA is a way of operationalizing learning as a part of regular human action and is not a claim about how human activity is organized. Its worth is to make more aspects of regular human action visible than what has been done within the conceptual-change account. Consequently, on analysis, these other aspects may turn out to have played a significant part in how the participants were able to (i.e., learned to) deal with a certain situation for a certain purpose. In this study, we used PEA to analyze how students’ reasoning progressed when the purpose was to explain how the galvanic cell in front of them worked, and what part taxonomic and correlational investigations as well as investigations into the conceptual and propositional explanations of [electro]chemistry played in this process.


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We present analyses of three instances in which the researcher initiated taxonomic or correlational investigations to support the student's explanation of how the real galvanic cell in front of them worked. As can be seen in the excerpts presented below, the taxonomic and correlational investigations constituted joint accomplishments between the researcher and the student (cf., Sensevy, Schubauer-Leoni, Mercier, Ligozat, & Perrot, 2005). This is emphasized in the concept encounter, which operationalizes a situation as what can be seen to meet or interact in the participants’ talk and action (Wickman, 2004). But the recognition that participants jointly take part in an activity does not preclude the possibility of pointing out who is contributing with what during the conversations. This is especially important in analyses of the consequences that certain encounters with a teacher or some other knowledgeable person have for how students’ learning is progressing (see, e.g., Lidar et al., 2006; Ligozat, Wickman, & Hamza, 2011). For instance, in the analyses below, we specifically highlight encounters involving the researcher initiating a gap leading to a joint taxonomic or correlational investigation, simply because it is the consequences of these particular and deliberately staged encounters with a more knowledgeable person that ultimately concern us here. Moreover, we also highlight instances when the student established relations involving a change in the way s/he coped with the purpose of explaining how the real galvanic cell worked. However, such highlighting of individual contributions does not constitute claims to the effect that those particular relations arose independently of the situation as a whole. On the contrary, they are made precisely to indicate that a particular encounter with the teacher had certain consequences for what the student was subsequently saying.

The first example is chosen for its straightforwardness and shows how Dave's explanation is supported by a joint taxonomic investigation between him and the researcher (Excerpt 1, Figure 2). Specifically, it shows how the taxonomic investigation became a reminder to Dave about some things that he obviously knew, but did not realize to be important when giving an explanation of the galvanic cell in front of him. The second and third examples, however, are instances where taxonomic and correlational investigations did not have any such direct consequence for Michael's and Cassandra's reasoning (Excerpts 2 and 3, Figures 3 and 4), which, of course, was the more common outcome of the researcher initiating these actions. Instead, it was by relating the outcomes of such investigations to each other in more subtle ways that Michael and Cassandra were able to continue their explanations of the galvanic cells in front of them. Michael's explanation was supported through a process involving investigations into both taxonomic issues and issues related to the generalized conceptual explanations that are necessary to explain how a particular galvanic cells works (Garnett & Treagust, 1992b). Specifically, the taxonomic investigation contributed to connect the generalized concepts to Michael's explanation of how his cell worked (Excerpt 2, Figure 3). Cassandra's reasoning was furthered through her relating investigations of taxonomic issues and issues of correlations to each other. In particular, through these two investigations Cassandra was able to sort out which details of the chemical processes of the galvanic cell could be excluded from her explanation of the real cell (Excerpt 3, Figure 4).

In the excerpts, brackets indicate pauses longer than 1 second (in whole seconds), square brackets contain either clarifications or indicate actions not visible through the transcript, and slashes (//…//) indicate parallel talk. Parallel talk is always indicated with reference to the previous turn (e.g., talk in Turn 3 is parallel to talk in Turn 2).

First Example: A Taxonomic Investigation Becomes a Reminder

Excerpt 1 and Figure 2 illustrate a direct consequence of a joint taxonomic investigation in which the constituents of the galvanic cell are distinguished and named. At the beginning of the excerpt, Dave gives an explanation of what is happening as the galvanic cell in front of him produces current (Turns 1–5; Figure 2, gap 1), with the researcher only giving short supportive comments. In our terminology, Dave has noticed and is trying to fill a gap directly related to the main purpose of the activity.


Excerpt 1

1Dave:Between uhm … It goes from, magnesium to copper, uhm, I think. The magnesium's a less noble … so I suppose it releases electrons, I think.
3Dave:… to the more noble copper, then. But … (2) Oh right it, releases electrons through, the lead and then … uhm … it does something through [chuckles] the liquids as well it … (3) well I mean both of them get, they get one thing each kind of.
4Researcher:Yeah, they get one thing each.
5Dave:[chuckles] I only remember electrons; I don't remember what the other stuff was.
6 [4 turns: Researcher suggests that Dave sketches his ideas on a piece of paper, Dave suggests that the glass filter lets through ions or electrons]

Dave succeeds in partly filling the first gap, which may be formulated as the implicit question “How do the electrons move in the cell?,” by construing the following relations: “It – goes from – magnesium to copper,” “Magnesium – less noble – releases electrons – to copper – more noble,” and “releases electrons – through the leads” (Turns 1–3). He then notices an additional gap (Figure 2, gap 2) about what is happening in the liquids (Turns 3 and 5). He is not able to fill this second gap. Because the two gaps are related, both gaps linger (Figure 2). In keeping with the purpose of the present study, the researcher then tries to provide support by initiating a taxonomic investigation, which is operationalized as introducing a gap about “what we have” before us. Thus, the researcher asks Dave to summarize what he has in the two compartments (Turn 7; Figure 2, gap 3).


Excerpt 1 continued

7Researcher:Mm. But why don't we summ-, why don't you summarize what you've got in the different, uhm … halves.
8Dave:Well, this is a, magnesium solution. //I mean//
10Dave:… it was magnesium sulfate wasn't it?
12Dave:Yeah right uhm … and then there's the magnesium.
14Dave:Yes. And here you've got copper sulfate and copper. So they're in their own solution kind of.
16Dave:(6) But then why[chuckles] … Uhm …
17Researcher:So, what have you got, you've got, pure, you've got magnesium.
19Researcher:Mm, and how … this one that you call magnesium sulfate, what kind of, uhm …
20Dave:Is it a //water solution?//
21Researcher://Yeah how would you// write that if you … wrote..?
22Dave:Uhm … M g … S O four, uhm, aqua [writes].
23 [Do the same with copper sulfate for 7 turns]
24Researcher:Aqua. And, when you write aqua there's a, you could, uhm … is it magnesium … In what form is magnesium and sul … you write magnesium sulfate and copper sulfate, aqua. But in, what form are they, they're in solution.
25Dave:Yeah yeah, it's a solution of them I mean, it's not that they…
26Researcher:Mm. Is it magnesium ions or magnesium atoms?
27Dave:It's ions. So //that they// can be in solution.

In Turns 8–28, the researcher and Dave jointly carry out the taxonomic investigation. In that process, they also fill several supplementary gaps, which are all related to the main taxonomic gap that the researcher introduced in Turn 7 (Figure 2; gap 3). In Turns 8–16, Dave begins to make certain distinctions, such as between “a magnesium solution” (Turn 8) and “the magnesium” (Turn 12). The researcher confirms that these and other similar distinctions are correct and relevant through comments such as “mm” and “yes” (Turns 9, 11, 13, and 15). In Turn 16, Dave seems to be trying to return to a more theoretical explanation but the researcher refocuses their attention to the joint taxonomic investigation (Turn 17), which he introduced in Turn 7. In Turns 19–25, the researcher is aiming to make Dave come up with a certain distinction through various forms of prompts (Turn 19) and scaffolds (Turns 21 and 24). Eventually, the researcher explicitly asks Dave to make the distinction (Turn 26): Are there ions or atoms in the solutions? Note that Dave immediately replies that the solutions contain ions and not atoms (Turn 27). Nothing in what the researcher has done up until this turn has hinted toward ions rather than atoms, but only that resolving in more detail what there is in the solutions is important when continuing the explanation of the galvanic cell. So, the distinction that Dave makes in Turn 27 is not new knowledge to him. However, reminding himself of this distinction together with learning, through the researcher's active guiding, that it constitutes a relevant part of his explanation seems to lead to a kind of sudden insight (Turn 29).


Excerpt 1 continued

29Dave:That's true!
30Researcher:So you've got magnesium ions and sulfate ions, and then you've got pure magnesium. //And here you have copper ions and copper//…
31Dave://Yeah that's it, that's what's happening isn't it!//
32Researcher:… //and then you've got copper//…
33Dave:… //that it// … copper …, ions from here attach to the copper and … here the magnesium comes off from … the solid to the… solution.

Hence, the relations construed in the joint taxonomic investigation (Turns 8–28) become a reminder of the relevance of this particular distinction for the purpose of giving an explanation of how the galvanic cell in front of him functions (Turns 29 and 31; Figure 2). As a consequence, Dave includes the distinction as a relevant part of his explanation of the real galvanic cell (Turn 33; Figure 2). Thus, once Dave and the researcher have jointly established that what they have in the solutions are ions (thus filling gap 3, Figure 2) Dave begins to construe relations to what might be happening in the solutions (Turn 33), which was precisely what he had stated that he was not able to do before the taxonomic investigation began (Turns 3–5). By filling a gap concerning certain distinctions in the cell (Figure 2, gap 3), Dave was also able to fill the initial gaps concerning the function of the cell (i.e., gaps 1 and 2, Figure 2). Thus, undertaking this taxonomic investigation together with the researcher, concerning constituents that are particular to the galvanic cell, had consequences for Dave's possibilities of giving an explanation of the function of the cell. Put differently, through the taxonomic investigation Dave learned to use the distinction between ions and atoms as a relevant part of the explanation begun in Turns 1–5.

Alternative Ways of Supporting Dave's Reasoning

Obviously, the researcher had other options for supporting Dave's explanation of the real galvanic cell rather than focusing on taxonomic issues related to the cell (Turns 3 and 5; Figure 2, gap 2). For instance, he could have drawn on his knowledge of student misconceptions regarding electric circuits and galvanic cells, for example, the misconception that electrons also move through the solutions (Garnett & Treagust, 1992b; Sanger & Greenbowe, 1997). Doing that might have been another route to make Dave realize that the ions in the solutions have a part to play in the explanation of how a current is produced in the galvanic cell.

Alternatively, he could have picked up Dave's relations “magnesium – releases – electrons – to copper” (Turns 1–3) and encouraged him to try to sort out what should happen to an electron once it reaches the copper electrode. This might have led Dave to conclude that some positively charged particles have to be involved in accepting the electrons arriving at the cathode. Or, he could have asked Dave to think about what will happen to a magnesium ion releasing electrons, thus helping him to realize that there will be a buildup of positive ions in the magnesium sulfate solution, and perhaps that these ions need to move somewhere to balance this.

These alternative ways of supporting Dave would have involved investigations into the generalized conceptual explanations of how galvanic cells work suggested by Garnett and Treagust (1992a, 1992b). Given the purpose of the present study, the researcher instead chose the option of initiating a taxonomic investigation concerning particular constituents of the actual galvanic cell in front of them (Turn 7). Engaging in a joint taxonomic investigation enabled Dave to have earlier knowledge of certain distinctions made relevant to the purpose of giving an explanation of how his galvanic cell works.

Second Example: A Taxonomic Investigation Is Made Continuous With Generic Explanations

Of course, most of the 44 taxonomic and correlational investigations that the researcher initiated did not have the straightforward consequences shown in Excerpt 1, in which certain distinctions directly supported Dave's explanation of how the galvanic cell worked. Instead, different kinds of investigations interacted in more subtle ways. In Excerpt 2 and Figure 3, we illustrate an instance in which a taxonomic investigation interacted with efforts to sort out more generic conceptual explanations of electrochemistry (cf., Garnett & Treagust, 1992b).

Michael has struggled for some time to explain what could be happening at the cathode and eventually suggests that something on that side tries to fill its valence shells as electrons move there (Turn 35).


Excerpt 2

35Michael:Yes. Well but it, in any case, they try to fill their shells. I'd say.
36Researcher:Mm. I'd say that too.
37Michael:But they r… this one [copper] releases its positive … or it, I don't know if it's got to release its positive …
39Michael:Considering that this one [magnesium] sends its negative ones here [to the cathode].
40Researcher:Right, so, one may rather think about, when the negative ones arrive here, at the //copper// …
42Researcher… is there anything in here that might accept those electrons?
43Michael:That would be sulf… solution, the copper sulfate //that// …
45Michael:… that is two plus.
47Michael:… that tries to … make itself even.
48Researcher:So it, and it's not the copper sulfate that's two plus but what in the copper sulfate is //two plus//?
49Michael://It's the// copper itself
50Researcher:Right, yes.
51Michael:So it's positively charged.
52Researcher:And it could consider taking up cop… electrons?
54Researcher:And then the question is what happens to a copper ion that accepts electrons?
55Michael:(2) Does it give off, no?

In Turns 37–39, Michael notices a gap concerning the function of the cell (Figure 3, gap 1) but cannot fill the gap that lingers (Turn 39; Figure 3). Note that the researcher's “no” in Turn 38 does not constitute a negative response to Michael's tentative suggestions in Turn 37. It is simply a normal response to a negative clause, perhaps more suitably translated with a “right” or “uh-huh” and thus serving the purpose of affirming that you are following the reasoning of the other person.

In line with the purpose of the study, the researcher then tries to support Michael's reasoning by introducing a taxonomic investigation. Consequently, the researcher introduces a gap about what might be “in here” that could be relevant to the explanation of what happens at the cathode (Turns 40 and 42; Figure 3, gap 2). In part, this measure is analogous to that in Excerpt 1 (Turn 7), where the researcher initiated a taxonomic investigation of what there is in the different half-cells in response to Dave's effort to produce an explanation of what happened to the cell in front of him. However, in this case, the researcher, through the relations that he establishes as he introduces the taxonomic investigation, actually presupposes that Michael's relation to “negative ones” (Turn 39) refers to electrons (Turn 42). An alternative intervention from the researcher could very well have been to begin the taxonomic investigation by instead sorting out what “its positive” (Turn 37) and “its negative ones” (Turn 39) may refer to in the first place.

Nevertheless, they jointly make the relevant distinctions in Turns 43–53, thus filling gap 2 (Figure 3). The researcher then invites Michael to connect this distinction to a generalized explanation (Turns 52–54; Figure 3). But as can be seen in Turn 55, Michael cannot make the connection. They therefore begin to sort out what happens to an ion when it accepts electrons (Turns 56–62; Figure 3, gap 3). This, then, is a joint investigation into a generalized explanation of chemistry.

Excerpt 2 continued

56Researcher:No, if you consider like this, let's make a drawing …
58Researcher:Here we've got Cu two plus
60Researcher:Then it accepts, I balance it here so that …
62Researcher:What happens to this one [the copper ion accepting an electron]?
63Michael:I'd say that it turns into an … an … [writing on the paper]
64Researcher:That's right
65Michael:It turns, neutral or it's got … it's got filled shells
67Michael:So it's … it's happy.
68Researcher:So the copper ions in this solution …
71Michael:… filled up their shells.
73Michael:And then … it's like, I think it's working like this … this, the galvanic cell will continue, as long as there's copper …, s u…, copper ions lacking filled shells.

Together they construe relations that fill gap 3 (Turns 63–67 and 68–71). As a result, Michael manages to partly fill also the initial gap concerning the function of the cell (Turn 73; Figure 3).

However, what happens at the cathode still needs to be established. The researcher now chooses to directly suggest a certain taxonomic distinction, namely that the layer on the copper foil is copper (Turn 74).


Excerpt 2 continued

74Researcher:And then would it be possible that what's covering this one … could it be copper?
77Michael:Actually it could be … yes, copper's probably forming on the copper foil itself.
78Researcher:Cause here you've got electrons coming.
80Researcher:And every copper ion bouncing against this copper foil will get access to two electrons.
81Michael:Right, then …
82Researcher:And then copper may form on this one.
83Michael:So does it turn into a solid substance when it accepts?
84Researcher://Yes//, you could say it's //solid// here don't you think?
85Michael://Yes// //Yes//.
86Researcher:Probably it's, you can't just wipe it off //like this//…
87Michael://No so it's// …
88Researcher:… but you could probably rub it off with steel wool if you wanted to.
89Michael:Yeah but, I'm satisfied with this.
91Michael:So you can see that there's formed…, there's… copper's formed on it.

They jointly carry out this second brief taxonomic investigation (Turns 74–77; Figure 3, gap 4), with Michael confirming the distinction directly suggested by the researcher in Turn 74 twice. Also jointly, although obviously primarily with the researcher establishing the important relations, they continue the explanation of how the cell works (Turns 78–82; Figure 3). Then, through his discrete question in Turn 83, Michael puts several previously construed relations together, thus establishing a relationship between what had been sorted out by filling gaps 2, 3, and 4 (Figure 3), respectively. By jointly filling gap 2 (Figure 3), a taxonomic investigation, Michael knew that the copper sulfate solution contained positively charged copper ions that may accept electrons (Turns 42–53). By jointly filling gap 3 (Figure 3), through an investigation into a generalized explanation, he also knew that charged copper ions will accept electrons and turn into uncharged copper atoms (Turns 54–67). Finally, by jointly filling gap 4 (Figure 3; Turns 74–76), another taxonomic issue, he knew that the visible precipitation on the cathode was copper. But it was not until Turn 83 that he was able to pull the threads from these different joint investigations together. Thus, the example illustrates the close interaction between resolving issues (e.g., distinctions) that are particular to the galvanic cell and more generalized explanations. It also shows that sometimes, direct telling from a more knowledgeable person may indeed lead to more than simple rote learning, which is evident from Michael's comprehensive question in Turn 83. Through the joint taxonomic investigations conducted, Michael was able to begin to situate the generalized explanation about what happens to ions accepting electrons in the real galvanic cell in front of him. And, conversely, by sorting out the generalized conceptual explanation, he was then able to begin making the particular distinctions pertaining to his galvanic cell part of the explanation of how this particular cell works.

Third Example: Taxonomic and Correlational Investigations Interact to Exclude Certain Details From the Explanation

In Excerpt 3, an investigation of correlations initiated by the researcher comes to the consequence that Cassandra excludes certain distinctions from her explanation of how the electrochemical cell can produce current. At the beginning of the excerpt, Cassandra and the researcher are engaged in giving an explanation of how the cell works (Turns 92–96: Figure 4, gap 1).


Excerpt 3

92Cassandra:And then they're positive, which means that electrons are coming … in from there and … form copper but that's not what's happened yet it might take some ….
93Researcher:Let's have it //going// for a //while//
94Cassandra:… //time// //Mm//
95Researcher:… and so we can check in a while, if we see anything
96Cassandra:That's what I think anyway, and then … there's released … (4) magnesium … (3) no, yes, magnesium ions are what … or is it sulfate, magnesium's not a gas
98Cassandra:(3) Sulfate, sulf… sulfur. (2) Could it be sulfur?
99Researcher:You're thinking of what it is //that … gives electrons//?
100Cassandra://What, yeah, what it is that's bubbling//.
101Researcher:Oh, you're thinking of what it is that's bubbling.
104Cassandra:And it's got to be, since it is … (2) magnesium can't bubble because it's, a metal.
106Cassandra:Oxygen maybe! (3) Sulfate but then would it dissolve, the ions somehow? (4) Cause it's you know, well …

They cannot fill gap 1 concerning how the cell works, which therefore lingers (Turn 96; Figure 4). Cassandra then notices another gap (Turn 96; Figure 4, gap 2) concerning the nature of the bubbles being produced in the magnesium half-cell, thus introducing herself a taxonomic investigation that they jointly carry out until Turn 106 (Figure 4). Contrary to the joint taxonomic investigations in Excerpts 1 and 2, however, they are unable to fill gap 2 with working relations, which means that this gap also lingers (Turn 106; Figure 4). Therefore, the researcher instead reminds Cassandra of a correlation they noticed a while before (Turn 107; Figure 4, gap 3) and initiates a further investigation of it (Turn 109).


Excerpt 3 continued

107Researcher:Mm. You noticed, didn't you, or you mentioned that it, you didn't expect it, to start bubbling right from the beginning, did you?
108Cassandra:No. I didn't expect that, I thought that it would need …
109Researcher:What do you think would happen if we pull this out [copper electrode]? If we take this one out of the solution?
110Cassandra:Then the circuit's interrupted.
111Researcher:Then the circuit's interrupted.
112Cassandra:So then, it should reasonably stop bubbling, maybe. Because they won't have anywhere to go. [Pulls out the copper electrode]



113Researcher:Well something's happening, it doesn't seem to stop bubbling but…
114Cassandra:But the fan stops.
115Researcher:The fan stops.
116Cassandra://Because there's released, it doesn't need to// …
117Researcher://Now it didn't start turning again// [after immersing the copper electrode]. We'll have to give it a push and I think it'll get going.
118Cassandra:Which way was it turning? (2) Really weak current.

Together they pursue this correlational investigation by establishing the relations “circuit – interrupted (Turns 110–111), “doesn't stop – bubbling” (Turn 113), and “fan – stops” (Turns 114–115). At this stage, their joint reasoning has consisted of efforts to produce an explanation of how the cell works, which ends up in gap 1 lingering, a concomitant taxonomic investigation, which ends up in gap 2 also lingering, and finally a correlational investigation, which ends up in filling gap 3. Eventually, in Turn 120, these three investigations all come together.


Excerpt 3 continued

120Cassandra:So that means that whatever it is that's bubbling it's got nothing to do … with the electron current.
122Cassandra:(5) And then what can it have been, could it have been… w… water it's like, is it water solutions?
123Researcher:It's water solutions.
124Cassandra:(2) So then it might, is it hydrogen gas maybe. Or oxygen gas it could be both and … I'd say it's hydrogen gas. Magnesium displaces hydrogen ions and produces hydrogen gas.
126Cassandra://It is//, right, then it has to be hydrogen gas. And that's got nothing to do with the electrolysis.
128Cassandra:So it's interrupted, that's right! So it's got effectively nothing to do with that but what's … it's magnesium … (2) ions … or magnesium atoms and copper … It should be, rather, that it's, breaking down.
129Researcher:What is?
130Cassandra:Z… zinc, uhm, the magnesium ribbon.

Through the relations that Cassandra construes in Turn 120, the outcome of the correlational investigation (“So that means that …”) interacts with the still lingering taxonomic gap (“… whatever it is that's bubbling”) and, as a consequence, the initial gap concerning the explanation of how the cell can produce current is partly filled (“got nothing to do … with the electron current”). Finally, they also fill gap 2 through another taxonomic investigation, thus establishing which constituents might be responsible for the bubbles (Turns 122–124). As a consequence of that Cassandra also extends the explanation begun in Turn 120 to “hydrogen gas – nothing to do with – the electrolysis [sic]” (Turn 126).

Here we see another interaction between the different investigations jointly conducted by the student and the researcher to further the explanation of the real galvanic cell in front of them. Thus, the taxonomic investigations (Turns 104–106 and 122–124) made Cassandra establish that the bubbles should be hydrogen gas. Through the correlational investigation, which the researcher initiated (Turns 107–115), she subsequently excluded hydrogen gas, which was the outcome of the joint taxonomic investigations, from her explanation of how a current can occur in the cell (Turns 120, 126, and 128).


Thus, the results show that, if a student is encouraged to engage in what we here call taxonomic investigations pertaining to the material present in a school science activity, this may sometimes have as a consequence that the student is reminded of knowledge that s/he had already come across but whose relevance for the present activity s/he had not appreciated until the taxonomic investigation was conducted (Excerpt 1, Figure 2). On other occasions, similar investigations may help the student to connect the concepts and categories of generalized explanations of a science topic to the present activity (Excerpt 2, Figure 3). At the same time, these same generalized conceptual and propositional explanations may help the student to connect the particular distinctions made to the broader field of electrochemistry (Excerpt 2, Figure 3). Finally, taxonomic and correlational investigations may interact to support the learning of what to include or exclude from the activity (Excerpt 3, Figure 4).


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Our results demonstrate that student learning in science is not only about making connections between a number of big ideas or central concepts of the area in question but also making these ideas continuous with particular distinctions and correlations pertaining to the concrete phenomena with which the students are supposed to cope in the classroom (Figures 2-4). Other authors have likewise suggested that accounts of science learning should pay attention to the concrete and particular aspects of school science tasks (diSessa et al., 2004; Hwang & Roth, 2007; Jiménez-Aleixandre & Reigosa, 2006). Here we have tried to further show in close detail how distinctions and correlations pertaining to encounters with these concrete aspects of school science can be turned into relevant parts of the students' learning through joint taxonomic and correlational investigations.

As is evident in the excerpts, however, the researcher did not restrict his contribution during these joint investigations to merely introducing a distinction or a correlation. Instead, he actively provided various prompts and scaffolds, which guided the student through the investigations in certain directions. One might argue that it was not the distinctions or correlations in our three examples, but rather the scaffolds and prompts given in relation to them, which were important for how the students were subsequently able to cope with the purpose of explaining their galvanic cell. However, in the present context neither the actual distinctions and correlations noted, nor the prompts and scaffolds provided by the researcher to make these continuous with the rest of the activity, can be singled out as standing on their own. As was pointed out in the Introduction in relation to the studies on which the present one is based, a taxonomic and correlational investigation is not only about actually learning a certain distinction or correlation. Indeed, sometimes the distinction itself was already common knowledge to the student (e.g., for Dave, Turn 27). Rather, the importance of a particular investigation lay precisely in learning that the distinctions and correlations noted were indeed worth taking into account in the explanation (which the students in those previous studies rarely managed to do when left on their own). So, the guiding role of the researcher is not a methodological problem for the present analysis but rather a necessary and integral part of making the taxonomic or correlational investigation meaningful in relation to the purpose of the activity. During the joint investigation between Dave and the researcher, for instance, the researcher's most important contribution, besides focusing Dave's attention on making the distinctions in the first place, was to provide precisely the prompts and scaffolds that guided Dave toward making this distinction a relevant part of his explanation. Without these scaffolds, it is possible that the continuity that Dave established between the distinction and his initial explanation would never have occurred. Indeed, this is why teachers are needed in the first place. Leaving out these prompts and scaffolds would be tantamount to simply providing the student with a note where the distinction or correlation has been stated. But it is not a claim of this study that certain distinctions or correlations, just by simply being there for the students to read or hear, would have certain consequences. Instead, our claim is that we may do well in doing the additional work of making certain distinctions and correlations relevant to the purpose of the activity, because these distinctions and correlations may be made continuous with each other and the generalized explanations needed to make sense of, in this case, how a real galvanic cell works.

Thus, although the researcher's support consisted of more than inviting the student to conduct joint taxonomic and correlational investigations, the results from this study demonstrate aspects of science learning which go beyond those generally considered in the scaffolding literature. As was pointed out already in the Background section, scaffolding primarily deals with various kinds of temporary support that are ultimately intended to be removed, as the student has acquired the appropriate level of proficiency. This kind of scaffolding was also given in the present study to support the learning, not only of generalized explanations but also of distinctions and correlations pertaining to the real galvanic cell. In other words, this study does not primarily deal with how a more knowledgeable person may assist students' learning, but rather what knowledge apart from the generalized concepts and ideas should be supported and what consequences learning of this additional content may have for students' possibilities of explaining a real phenomenon in front of them. This difference clearly makes this study an important complement to the main body of work on student–teacher dialogue and scaffolding by focusing primarily on the content of the interaction.

Our results, then, provide new insight into the details of what it may look like in students' reasoning if they are encouraged to focus not only on the generalized explanations of a science topic but also on the particular and contingent aspects of the school science activity in which they are engaged. The examples indicate that learning the generic and abstract knowledge of science does not necessarily have to be accomplished through more of the same. Instead, diving into some of the particular or contingent aspects of the activity of which one is presently part may be a productive route for taking one's reasoning further. Indeed, two key characteristics of contingent processes are that similar endpoints may be reached by very different routes, and through radically different events along the way (Pickering, 1995). So, in the broadest sense, our results indicate that we may need to approach learning in science more as this kind of contingent process, the direction of which is continually affected by several of the aspects being part of an experience. If this is so, the incentive for laying out possible learning trajectories primarily for the acquisition of a number of big ideas would become significantly weaker. Instead, we would need to begin producing far more complex, but at the same time hopefully more useful, hypotheses about what students need to learn as they progress through the science curriculum.

Our results may also be seen as descriptions of the processes involved in the appropriation of sociocultural tools, for instance, the concepts of electrochemistry, during school science activities (Jakobsson, Mäkitalo, & Säljö, 2009; Kelly & Chen, 1999; Roth, 1999). Indeed, the process of appropriation involves learning when and how to use a tool, such as a scientific concept, in relevant ways in a certain activity (Wells, 2008). For instance, through the taxonomic investigation that Dave conducted together with the researcher, he learned how to use previously known concepts and categories to get things done on this particular occasion in relation to its particular purposes (cf., Wells, 2008). This is no doubt most often accomplished as people come across new situations in which the tool may be used with different consequences. As such, it constitutes an open-ended process of learning ever-finer ways of using the tool. Our results suggest, however, that introducing taxonomic and correlational investigations into a learning activity might constitute a more focused and deliberate way of actively supporting this appropriation process in the science classroom.

Finally, our results may be seen as providing detailed accounts of the processes by which students situate what they learn during a school science activity in both the particulars and contingencies of that activity and in the generalized explanations of the topic. In our examples, the students learned aspects, such as what to include or exclude or what knowledge is relevant for the activity, which are commonly associated with situated learning and its concomitant participation metaphor (Scott et al., 2007; Sfard, 1998). But we show that these aspects were closely tied to the students' possibilities of giving a scientific explanation of how their galvanic cell worked, that is, with knowledge more often associated with the acquisition of the concepts and generalizations of science.

The results from this study support the claim that there is much more involved in the process of progressing toward increased competency in school science, here operationalized as providing explanations for a real natural phenomenon, than the ways in which students use generalized conceptual and propositional explanations (Hamza & Wickman, 2009; Wickman & Ligozat, 2010). Other authors have come to similar conclusions on the basis of both empirical (Greeno, 2006; Jiménez-Aleixandre & Reigosa, 2006; Kelly & Green, 1998; Lindwall & Lymer, 2008; Roth & Hwang, 2006) and theoretical (Garrison, 1995; Kruckeberg, 2006; Wong & Pugh, 2001) grounds. Yet, the science education community continues to privilege the big ideas and generalizations of science in hypotheses of how students progress toward increasingly more scientific explanations of natural phenomena (e.g., Corcoran et al., 2009; Duncan & Hmelo-Silver, 2009; Scott et al., 2007; Smith, Wiser, Anderson, & Krajcik, 2006). Our three examples, on the other hand, suggest that what students learn, apart from the big ideas and generic explanations of science, should not be relegated to a separate realm, as if that learning was something set aside from learning to deal scientifically with various phenomena around us. During any science learning activity, students need to learn how to make appropriate distinctions, what aspects are relevant to pay attention to, what counts as good, bad, or beautiful in science, and how to use generalized concepts to explain the phenomena around them. Obviously, these aspects interact in important and nontrivial ways and therefore need to be made continuous with each other to further the student's understanding of the science topic. Through the PEA, we were able to examine and concretely illustrate what this continuity may actually look like in action (cf., Figures 2-4).

Specifically, we have demonstrated that due consideration of aspects other than the big ideas of the topic in question constitute potentially productive points of departure for teachers supporting students' learning of science. One way to handle these results in the science classroom would be to treat these other aspects that are more tied to the specific contexts and concrete materials of the activity separately from the more general concepts that apply in a particular situation. However, this may not be the most straightforward conclusion considering the results from this study. Instead, it seems as though students may need help precisely to establish links, or continuity in PEA terms, between the more generalized concepts and explanations on the one hand and the particular and contingent aspects of the situation on the other, to come to terms with the scientific point of view when facing a natural phenomenon. From that point of view, the results illustrate possible and alternative learning trajectories in which familiar difficulties that the students come across during virtually every normal assignment in any science classroom may be turned into productive resources for their further learning. Here, these difficulties were referred to as the need to learn the relevance of certain distinctions and correlations to provide a scientific explanation of a real phenomenon. After all, every teacher knows that these sorts of issues need to be dealt with anyway; only, they are usually seen more as a necessary evil than as possible assets for coping with the main purpose of a science learning activity, particularly during laboratory work (Kirschner & Huisman, 1998; White, 1996). Therefore, one possible direct implication for teaching from this study might be that we may actually calculate our students' need to resolve taxonomic and correlational issues during laboratory work as important events that, by being made continuous with the more generalized knowledge to be learned, may increase their possibilities of coping with the main purpose of the laboratory. Another possible conclusion might be that we need to begin supplementing learning progressions including the big ideas also with these other aspects and see how these might fit into the bigger picture.

Still, the present study is limited to presenting a few intriguing examples of alternative, and perhaps often neglected, learning trajectories that take into account the messy contingencies of real practice as assets for student learning, as opposed to trying to eliminate them from the learning experience. If the examples presented here can be applied more generally, considerably more effort would need to be put into the systematic description of the interactions between the vast array of aspects that come into play as students learn science in the classroom, as well as to how they can be made continuous with each other in the progressions of students' learning over time. The results from this study constitute one step toward such an effort.


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This study is part of the project “How Can Teachers Aid Students Towards Scientific Reasoning” funded by the Swedish Research Council. This research was also part of the research project “Learning, Interactive Technologies and the Development of Narrative Knowing and Remembering” in cooperation with Göteborg University, Linköping University, and Uppsala University financed by the Knut and Alice Wallenberg Foundation, Riksbankens Jubileumsfond, and the Swedish Research Council.

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    Our finding that situated explanations of real phenomena (such as a real galvanic cell) involve more aspects than those commonly acknowledged in studies of students' generalized explanations (such as those produced in clinical interviews) shows interesting affinities with the distinction between causal and mechanistic explanations in scientific (Machamer, Darden, & Craver, 2000) and student (Russ, Scherr, Hammer, & Mikeska, 2008) discourse. Machamer et al. (2000) argued that scientific explanation crucially concerns the description of mechanisms. Such mechanisms, moreover, are composed of two constitutive parts, namely entities and their activities (Machamer et al., 2000). Russ et al. (2008) later proposed a framework for analyzing students' scientific reasoning based on this notion of mechanism in scientific inquiry. Here we simply want to point out that resolving taxonomic issues may be seen as one way of identifying (i.e., distinguishing and naming) the relevant entities and activities of a particular mechanism (e.g., for how a galvanic cell works). Likewise, students' need when dealing with correlations may be partly equated with identifying the relations between the entities and activities that are recognized as part of a mechanistic explanation. Although this is not the place, we feel that a more detailed comparison between the two frameworks could indeed generate interesting results.


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