Elementary teachers' pedagogical content knowledge for teaching the nature of science

Authors


Abstract

Although teacher educators have achieved some success in improving teachers' understanding of the nature of science (NOS), helping teachers teach NOS has proved a much greater challenge. Currently, there are few examples in the literature of teachers who effectively teach NOS, and fewer still that rely on student outcomes as a measure of teachers' effectiveness. Much remains to be understood regarding the sources, nature, and development of teachers' pedagogical content knowledge (PCK) in regard to NOS. Using S. Magnusson, J. Krajcik, and H. Borko's (1999) framework, we examined the PCK for NOS of three elementary teachers who have been successful in improving their students' understanding of NOS. We relied on interviews, questionnaires, classroom observations, and classroom artifacts collected over a 3-year period to characterize their PCK for NOS. Although each had robust knowledge of instructional strategies for teaching NOS, teachers lacked the requisite knowledge of assessment that would provide a feedback loop to support continued development of their knowledge of learners and lead to improvement in their teaching of NOS. Our findings highlight a need for professional development that focuses on developing aspects of PCK for NOS such as teachers' knowledge of assessment as well as educative curriculum materials to support continued development of teachers' PCK for NOS in practice. © 2010 Wiley Periodicals, Inc. Sci Ed95: 145–167, 2011

INTRODUCTION

There is widespread consensus that effective teachers are a critical factor for student learning. Teachers must not only understand subject matter and pedagogy but be able to transform such understandings within their teaching practice so their students can conceptualize new ideas (Shulman, 1986). In science, subject matter includes understandings about nature of science (NOS). Although efforts to improve teachers' knowledge of NOS (Abd-El-Khalick, 2001; Akerson et al., 2000, 2004; Akerson & Hanuscin, 2007) have met with some success, helping teachers successfully teach NOS has proved a much greater challenge. Further research is needed regarding how teachers who understand NOS translate such understandings into their classroom practice (see Bartholomew, Osborne, & Ratcliffe, 2004). This study focuses on three elementary teachers who improved their understandings of NOS through a 3-year professional development program. Using the theoretical framework of pedagogical content knowledge (PCK), we explored the kinds of knowledge and practices used by these teachers as they successfully translated NOS into forms accessible to their elementary students.

LITERATURE REVIEW

The Nature of Science

NOS has been underscored as a critical component of scientific literacy in science education reforms (American Association for the Advancement of Science [AAAS], 1990, 1993; National Research Council [NRC], 1996) as well as in a position statement of the National Science Teachers Association (NSTA) (2000). NOS refers to understanding science as a way of knowing, or the values and beliefs inherent to the development of scientific knowledge (Lederman, 1992). As Driver, Leach, Millar, and Scott (1996) emphasize, understanding NOS helps individuals become informed consumers of scientific information, make sense of socioscientific issues, participate in decision-making processes, and appreciate science as a part of contemporary culture.

It should be noted that U.S. reform documents such as the Science for All Americans (AAAS, 1990) provide a simplified and noncontroversial account of what remains an area of much debate among historians, philosophers, and sociologists of science (Duschl, 1994), though there is some degree of consensus regarding the importance of these ideas about science to science education (Osborne, Collins, Ratcliffe, Millar, & Duschl, 2003). We adopted a pragmatic approach, used by Lederman and others, that focuses on seven broad aspects of NOS common to the reforms. These were articulated by the NSTA in its 2000 Position Statement on the Nature of Science, specifically, that (a) scientific knowledge is both reliable (one can have confidence in scientific knowledge) and tentative (subject to change in light of new evidence or reconceptualization of prior evidence); (b) no single scientific method exists, but there are shared characteristics of scientific approaches to science, such as scientific explanations being supported by empirical evidence, and testable against the natural world; (c) creativity plays a role in the development of scientific knowledge; (d) there is a relationship between theories and laws; (e) there is a relationship between observations and inferences; (f) although science strives for objectivity, there is always an element of subjectivity in the development of scientific knowledge; and (g) social and cultural contexts also play a role in the scientific endeavor. We chose to focus on these particular ideas about science during the professional development program because they were in line with the state standards teachers were expected to teach, and thus they also served as a frame for the current study; however, we acknowledge this is but one way to conceptualize NOS and to approach teaching NOS. Recent work has criticized this approach for provided a limited account of the pedagogical relevance of teachers' understanding of NOS (e.g., Guerra-Ramos, Ryder, & Leach, 2010). To address this concern, in the present study we provide a rich account of how teachers internalize these aspects of NOS and how that knowledge manifests itself in their practice.

Effectively Teaching NOS: The Need for Explicit Instruction

Research has demonstrated that to teach NOS effectively, teachers must make aspects of NOS an explicit part of the classroom discourse. Rather than utilizing didactic means, teachers should provide learners with opportunities to reflect upon and explain their ideas about NOS, discuss the strengths and limitations of those ideas, and assess the consistency of their ideas with those of others (Schwartz & Lederman, 2002). For example, Khishfe and Abd-El-Khalick (2002) found that sixth-grade students who engaged in inquiry-based learning and had explicit instruction about NOS improved their NOS understanding, whereas those who engaged in inquiry-based learning where NOS was an implicit component of instruction did not. Similarly, Akerson and Abd-El-Khalick (2003, 2005) found that despite immersion in inquiry-based instruction, fourth-grade students' views of NOS were not improved when the teacher neglected to provide explicit instruction. Akerson and Volrich (2006) found that a student teacher who had sufficient understanding of NOS, as well as intentions and motivation to teach NOS, could effectively implement strategies for explicitly emphasizing NOS within her instruction. This resulted in improvements in first graders' views of the tentative, inferential, and creative NOS.

It is important to note that when student outcomes have been used to gauge the effectiveness of teachers' NOS instruction, as in the studies above, improvements in students' understanding of NOS have typically been identified through researchers' instruments versus teachers' own classroom-based assessments. Although there has been much debate among science educators as to the best way to assess understanding of NOS for research purposes (Chen, 2006; Elby & Hammer, 2001; Lederman, Abd-El-Khalick, Bell, & Schwartz, 2002), teachers' strategies for assessing their students' understanding of NOS have received minimal attention in the current body of research. By definition, an explicit approach is one in which NOS understandings are “…intentionally planned for, taught, and assessed (emphasis added)” (Lederman, Schwartz, Abd-El-Khalick, & Bell, 2001, p. 137). To develop a robust understanding of teachers' classroom practices, such as their use of explicit approaches to NOS, we argue that teachers' assessment practices should be considered.

Assessment of NOS as a Component of Explicit Instruction

If we assume effective NOS instruction is that which results in student learning about NOS, then it logically follows that assessment of students' ideas about NOS serves as an important component of teachers' classroom practice. Presently, research has focused almost exclusively on teachers' use of instructional strategies; descriptions of teachers' assessment practices related to NOS are at best vague. Several studies that have considered teachers' assessment of NOS (though not as a central focus of the research) reveal that teachers do not assess student ideas' using formal assessments (Abd-El-Khalick, Bell, & Lederman, 1998). Rather, teachers may informally assess NOS based on questioning in class (Schwartz & Lederman, 2002) or intuition about how the lesson “worked” with students (Bartholomew et al., 2004). Teachers who have been reported to have formally assessed NOS have done so through more traditional means. For example, Lederman and colleagues noted a teacher who wrote “two exam questions aligned with his two objectives on scientific models (inference) and tentativeness” (2001, p. 152). Similarly, Bartholomew and colleagues (2004) cited teachers' intentions (though not carried out) to test students' understanding of the words “observation” and “inference.”

From the limited evidence currently available in the research literature, it is unclear whether teachers are neglecting to assess their students' understanding of NOS or simply do not possess the necessary knowledge and skills to do so. By utilizing PCK as a framework for the study, we hope to develop a more complete view of elementary teachers' knowledge, skills, and classroom practices related to NOS.

Purpose of the Study

Given PCK usually develops as a result of extensive and extended experiences teaching a specific topic and that teaching experience is one of several variables shown to mediate and constrain the translation of teachers' views of NOS into their teaching practice (Abd-El-Khalick et al., 1998), there is a need to focus on experienced classroom teachers who have successfully improved their students' views of NOS. Such perspectives might better inform our understanding of how to support novice teachers. In this study, we examine the classroom practices of three experienced elementary teachers who, through explicit-and-reflective instruction, successfully improved their students' understanding of NOS. The teachers were part of a 3-year professional development program focused on NOS and inquiry (Akerson & Hanuscin, 2007). Through multiple data sources, we examine how teachers' understanding of NOS manifests itself in their classroom practice, including their instruction, but also, importantly, their assessment of students' ideas. We rely on the construct of PCK as a theoretical lens to help us better understand the interplay between the various knowledge bases that teachers draw on as they plan and enact NOS instruction and assessment. The overarching research questions guiding our work include the following:

  • 1.How do teachers transform their understandings of NOS into representations that are accessible to K-6 learners?
  • 2.How are teachers' practices constitutive of their PCK for NOS?

THEORETICAL FRAMEWORK

Pedagogical Content Knowledge

Shulman (1987) first introduced the notion of PCK as a fundamental component of the knowledge base for teaching. PCK, according to Shulman, is what makes possible the transformation of disciplinary content into forms that are accessible and attainable by students. This includes knowledge of how particular subject matter topics, problems, and issues can be organized, represented, and adapted to the diverse interests and abilities of learners and presented for instruction. It represents the synthesis of teachers' knowledge of both subject matter and pedagogy, distinguishing the teacher from the content specialist. The development of PCK involves a dramatic shift in teachers' understanding

from being able to comprehend subject matter for themselves, to becoming able to elucidate subject matter in new ways, reorganize and partition it, clothe it in activities and emotions, in metaphors and exercises, and in examples and demonstrations, so that it can be grasped by students. (Shulman, 1987, p. 13)

Shulman's model has been elaborated upon and extended by other scholars (e.g., Grossman, 1990; Magnusson, Krajcik, & Borko, 1999). As van Driel, Verloop, and de Vos point out, while there is no universally accepted conceptualization of PCK, there is agreement with two key elements of Shulman's model—knowledge of representations of subject matter and understanding of specific learning difficulties and student conceptions (1998). In addition, they emphasize that there is some consensus on the nature of PCK. First, that it refers to particular topics, and therefore is distinct from general knowledge of pedagogy, educational purposes, or learner characteristics; second, that it differs from subject matter knowledge (SMK); and third, that PCK is developed through an integrative process rooted in teachers' classroom practice, implying that beginning or novice teachers will have relatively undeveloped PCK.

In the present study, we relied on the transformative model of PCK of Magnusson et al. (1999) that includes five interacting components: (a) orientations toward science teaching, (b) knowledge and beliefs about science curriculum (goals and objectives/curriculum and materials), (c) knowledge and beliefs about students' understanding of specific science topics (prerequisite knowledge and student misconceptions), (d) knowledge and beliefs about assessment in science (dimensions of science learning to assess and knowledge of methods of assessment), (e) knowledge and beliefs about instructional strategies for teaching science (topic-specific activities, e.g., activities for teaching photosynthesis; as well as subject-specific strategies, e.g., inquiry).

PCK for NOS

Within the various domains of teacher knowledge, understanding of NOS can be considered part of teachers' SMK—more specifically, their syntactic knowledge of science, which includes knowledge of the source and justification of scientific knowledge. According to the model of Magnusson et al., SMK influences PCK; however, as Lederman points out, “the relationship between one's views of NOS, subject matter, and pedagogy remains uncertain” (2007, p. 870).

In terms of teaching NOS, researchers have argued that NOS be viewed as a cognitive, rather than affective outcome of instruction (Abd-El-Khalick, 2001) and that NOS is as much an aspect of subject matter as the reactions of photosynthesis or pH (Lederman, 1998). In other words, NOS may also be viewed as a particular topic within the domain of science. This is further evidenced by the inclusion of NOS as one of the content standards in the National Science Education Standards (NRC, 1996). Thus, while teachers' own views of NOS can be considered part of their SMK, NOS can also be viewed as analogous to other content a teacher might teach, and for which they would develop PCK.

Despite numerous investigations into the development of PCK throughout all disciplinary areas and science in particular (e.g., Gess-Newsome & Lederman, 1999), “the nature and development of teachers' PCK for NOS is an area of research that has yet to be investigated” (Lederman et al., 2001). Several studies have alluded to the impact of interventions on teachers' PCK for NOS (Akerson & Abd-El-Khalick, 2003; Akerson & Volrich, 2006) but have not investigated the sources, nature, and development of PCK for NOS in any systematic way. “Virtually no research has used the PCK perspective, which was so heavily researched during the 1990s, as a lens for research on the teaching of NOS” (Lederman, 2007, p. 870). Several efforts have been made, however, to articulate PCK for NOS.

In addition to adequate understanding of NOS, Abd-El-Khalick and Lederman (2000) propose that teachers' PCK for NOS would include

…knowledge of a wide range of related examples, activities, illustrations, demonstrations, and historical episodes. These components would enable the teacher to organize, represent, and present the topic for instruction in a manner that makes the target aspects of NOS accessible to pre-college students. Moreover, knowledge of alternative ways of representing aspects of NOS would enable the teacher to adapt those aspects to the diverse interests and abilities of learners …. [T]eachers should be able to comfortably discourse about NOS, design science-based activities that would help students comprehend those aspects, and contextualize their teaching about NOS with some examples or “stories” from history of science. (pp. 692–693)

In later work, Schwartz and Lederman (2002) proposed an emerging model of critical elements for the development of PCK for NOS and application of that knowledge in the classroom. According to these researchers, knowledge of NOS, knowledge of science subject matter, and knowledge of pedagogy are just three of the elements that blend to form PCK for NOS. They argue that to be able to teach NOS, teachers must intend and believe they can teach NOS, must believe that their students can learn NOS and must have the knowledge base for teaching NOS (Schwartz & Lederman, 2002).

We concur with Lederman's arguments (1998) that PCK for NOS is analogous to PCK for other topics; however, we argue the present descriptions of PCK for NOS do not represent alternative ways of viewing of PCK but include elements that can be mapped onto existing models for PCK. For example, teachers' knowledge of historical episodes that could be used to illustrate particular aspects of NOS and analogies that could help students understand NOS are part of a teacher's knowledge of instructional strategies (cf. Magnusson et al., 1999).

Our study was guided by the assumption that our teachers, having improved their understandings of NOS during the professional development, had sufficient SMK of NOS to teach it. In addition, because they had successfully improved their students' views of NOS, we assumed they had relatively well-developed PCK for NOS. By examining their classroom practices in-depth, our intent was to identify aspects of their practice relative to the different domains that comprise PCK. As emphasized by Abell (2008), however, while the discrete components of PCK in the model of Magnusson et al. (1999) can serve as useful tools for researchers, PCK is more than the sum of its parts. Thus, we also sought to examine the interplay between the components of PCK as teachers enacted NOS instruction.

METHODS

Research Design

Our efforts reflect a critical reexamination of data from a previous study (Akerson & Hanuscin, 2007) or what Heaton (1998) refers to as secondary analysis. While already a common and generally accepted mode of inquiry in quantitative research, secondary analysis is increasingly being utilized in qualitative inquiry (Heaton, 2004). Within this framework, researchers utilize “retrospective analysis of the whole or part of a data set from a different perspective, to examine concepts which were not central to the original research” (Heaton, 1998).

Our initial study focused on the impact of a multiyear professional development program on teachers' views of NOS and instructional practices, as well as the impact of teachers' instructional practices on students' understandings of NOS. Our primary interest was identifying features of the program that effectively supported teachers in developing their abilities to teach NOS. In the present study, we focus on the broader question, what can we learn about PCK for NOS by examining the practices of elementary teachers who are “effective” in teaching their students about NOS? Specifically, we examine (1) the ways in which teachers transformed their understandings of NOS into representations that are accessible to K-6 learners and (2) how they draw on the various component knowledge bases that comprise their PCK. In this way, our work transcends our original study by examining teachers' practices through a PCK lens.

As Thorne (1994) emphasizes, in presenting a secondary analysis, researchers should include an outline of the original study and data collection procedures, together with a description of the processes involved in categorizing and summarizing the data for the secondary analysis, as well as an account of how methodological and ethical considerations were addressed. Appropriately, we provide this account in the sections that follow. Additional information can be found in Akerson and Hanuscin (2007).

Context

The Inquiry Teacher Study Group1 was a single-school professional development program that focused on developing teachers' understanding of NOS and scientific inquiry and empowering them to teach in ways that foster students' understandings of these as well. During initial workshops, teachers were introduced to aspects of NOS advanced by the reforms (AAAS, 1990, 1993; NRC, 1996) and participated in inquiry-based experiences designed to illustrate these aspects of NOS. In addition, teachers examined their curricula to determine whether and how NOS and inquiry were emphasized. Workshop sessions focused on strategies for teaching NOS and inquiry in the elementary classroom and included collaborative planning sessions for adapting curriculum.

Throughout the 3 years of the program, project staff (first and third authors) provided support to participants by teaching model lessons, coteaching collaboratively planned lessons, observing and providing feedback to teachers about their instruction, and assisting in preparing presentations and publications of teachers' work through professional organizations (conferences, monographs, etc.). We examined the impact of the professional development on teachers' understanding of NOS and instructional practices, as well as the impact of teachers' instruction on students' understandings of NOS (see Akerson & Hanuscin, 2007). We found that though the teachers held misconceptions about NOS at the outset of the program, their views improved substantially over the course of their participation. In addition, they began to emphasize NOS explicitly in their instruction following modeling of this instruction by the professional developers. We found monthly workshops, coupled with individualized classroom support, successfully improved teachers' NOS views and teaching practice.

Participants

Six of the fourteen classroom teachers at Parker2 Primary School participated in the program through a series of monthly half and full-day workshops (n = 19) over 3 years. Only three teachers consented to participate in the research component of the project; however, these teachers were representative of their colleagues in terms of teaching experience and background. Cameron3 had 29 years of teaching at the kindergarten level, Jennifer had 5 years experience at the first-grade level, and Kayla was in her second year of teaching a combined fifth–sixth-grade class. Each of the teachers had clear intention to teach NOS, which Schwartz and Lederman (2002) emphasize as critical to teachers' PCK for NOS. Conversations among teachers during a final debriefing at the end of the project revealed teachers' rationales for teaching science as inquiry and emphasizing NOS, which included fostering students' enjoyment of science, empowering students to do science, and supporting student learning:

Researcher: We've been talking about the nature of science—why do you feel it's important to teach that? What would you explain—what's motivating you?

Jennifer: For me, it's like giving the kids the empowerment that they can do this on their own—I think we all started in the place that science is this “other” thing and that we were all kind of intimidated by it, and having the kids see themselves as scientists, and be willing to try out an idea, knowing that it could work or not—but not having that fear—that's where I come from …

Kayla: I think for me, it was—I remember when I took my methods class for science, it was a lot different—and I was like this is really neat, there are some really neat things—I felt like I left with some good ideas about it, but then, when I actually got to the classroom and I did my first year of science I kind of felt oooh … this is hard, I don't like this book, I don't like this, and I felt kind of icky about it so I would just push it to the side, like, well, it's OK if we get to just a little bit of it. And then from doing this [workshop], I feel it to be more of a priority for me, and I find that the kids enjoy it and like it—I think it made me realize more of the importance of [science]. It gave it a much more important place in my classroom than it was to me a few years ago ….

Cameron: I initially did it because I never liked teaching science, and I feel like I've done a poor job of it in the past. And maybe because I've done, you know, some of those activities that are described in the one article—they're hands-on, but they're not really learning anything—I felt like this would be good for me, and I think it has, and I think what's happened is, it's evolved into me realizing, like Jennifer says, this is really how people learn, and so I've gotten really excited …. [Transcript 5.13]

We considered these teachers “effective” in teaching NOS because they had a clear rationale and commitment to teaching NOS as well as the ability to emphasize NOS explicitly in their instruction. Most importantly, we had determined through our research that their instruction had positively impacted their students' views of NOS. In the third year of the program, interviews were conducted at the beginning and end of the school year with a subset of teachers' students using the VNOS-D (Lederman & Khishfe, 2002). The size of this sample was limited by parents' willingness to provide consent, as well as students' ability to participate in both interviews. In all, we were able to interview 15 of the 40 students in Cameron's class (two half-day K classes), 8 of 24 students in Jennifer's class (first grade), and 10 of the 24 students in Kayla's class (fifth–sixth-grade split). Table 1 illustrates the changes in students' views of five aspects of NOS targeted in the workshop and emphasized by teachers in their lessons. Further details of specific changes in students' views are described in Akerson and Hanuscin (2007).

Table 1.  Number of Students Holding Adequate Views of NOS
 EmpiricalObservation and InferenceCreative and ImaginativeTentativeSubjective
Teacher-Grade LevelPrePostPrePostPrePostPrePostPrePost
Cameron-K0477350101
Jennifer-10246351523
Kayla-51233133322
Kayla-61355032302

Arguably, teachers normally would not have researchers assessing learning outcomes of their students, and so we were interested in exploring teachers' own perceptions of the impact of their instruction on students' understanding of NOS and the ways in which they gathered evidence of the effectiveness of their instruction.

Data Sources

The nature, richness, and diversity of available data from the first study meet Heaton's criteria of compatibility with the secondary analysis. Furthermore, the first and third authors' roles as primary analysts in the first study position us to have access to the original data in line with the original informed consent of participants. Keeping in mind that PCK can be more richly understood through multiple data sources, we sought to capture teachers' PCK in action as well as in their discussion of their teaching. We selected the following data sources from our first study for use in our secondary analysis: (1) questionnaire and interview data collected at the beginning and end of the project to document teachers' own understanding of NOS; (2) fieldnotes and transcripts from 15 full and/or half-day professional development sessions held over a 3-year period; (3) videos, lesson plans, and fieldnotes from 15 separate observations of teachers' classroom teaching of NOS over the course of the project; (4) video stimulated-recall interviews conducted with teachers following each of these classroom observations; (5) videos, transcripts, and artifacts from teachers' presentations of their teaching experiences at both a state and regional professional conference; (6) teachers' written contributions to professional publications, including two chapters in NSTA monographs; (7) individual interviews conducted with teachers at the end of Years 1 and 2 of the project; and (8) a focus-group session held with teachers at the conclusion of the project.

Analysis

We utilized modified analytic induction (Bogdan & Biklen, 1998; Taylor & Bogdan, 1984) to develop our coding schema and identify emerging themes. Independent examination of the data by each of the researchers and comparison of analyses was used to establish credibility of our findings. We began with a thorough review of all data sources, assigning codes and making analytic memos to denote instances relevant to teachers' explicit instruction and assessment of NOS. Judgments about what constituted an explicit approach were rooted in four overarching criteria—that teachers (a) planned to teach a particular aspect of NOS; (b) students were made aware of the target aspect of NOS; (c) students were provided an opportunity to discuss and/or reflect on their ideas about the target aspect of NOS; and (d) teachers elicited students' ideas about NOS before, during, or at the conclusion of the activity. Themes and categories emerged through an iterative process of engagement and reengagement with the data (Strauss & Corbin, 1998). At this stage, we sought to examine the extent to which teachers' practice reflected the types of instruction we modeled for them in the professional development and how they modified their instruction to meet the needs of their particular students. Matrices were used to triangulate data and track themes across multiple data sources for individual teachers, allowing us to identify gaps, overlaps, patterns, and trends. Through this process, we sought to identify common aspects of teachers' instruction and assessment of NOS. As assertions were generated, we actively searched the data for negative cases, modifying our assertions to account for these as necessary. As our analysis proceeded, we refined our focus to consider more precisely what it means to translate one's understanding of NOS into forms accessible to learners, and how one might make judgments about the success of these efforts. Our data, therefore, represent the efforts of our teachers not only to understand NOS themselves but to help their students understand NOS. The different ways and extent to which these teachers did so provide us insight into their PCK for NOS.

FINDINGS

Teachers' Classroom Practices and Representations of NOS

According to the National Science Education Standards (NRC, 1996), effective teachers must select science content and adapt their curricula to meet the interests, knowledge, understanding, abilities, and experiences of students. That is, teachers will rarely implement lessons “as is.” Although the professional development program modeled explicit-and-reflective teaching strategies, teachers were challenged to adapt these strategies within their own classroom contexts. Our first research question was concerned with the ways in which teachers did so. In our analysis, we identified three distinct, but related, ways through which teachers transformed their understanding of NOS into forms accessible to their students. These consisted of (1) translating the language of the reforms into “kid-friendly” terms, (2) operationally defining NOS in the context of inquiry-based experiences, and (3) drawing analogies to NOS aspects using children's literature. Below, we discuss each of these transformations and what they reveal in terms of teachers' PCK for NOS.

Translating the Language of the Reforms

Despite teachers' belief that students were capable of learning through inquiry, they nonetheless questioned the appropriateness of using the terms for NOS from the workshop with their elementary students. During one session, they raised the question whether the phrase “nature of science” was necessary to use with elementary students. The facilitator, an invited speaker and expert in NOS, explained to them that it was not explicitly using the phrase “nature of science” but being explicit about the ideas about NOS that was critical:

I don't even call it “nature of science” with kids, but I use some of these words, or some form of these words. …Empirical means that scientists collect data. Use whatever words work that help your students understand the underlying concepts. [Transcript 5.16]

Although teachers questioned the appropriateness of the vocabulary, they nonetheless believed their students were capable of learning these ideas. Following this episode, teachers collaborated to create of a series of posters for their classrooms that employed what they believed were age-appropriate terms for each of the aspects of NOS to which they had been introduced. This transformation of their understanding of NOS into their classroom practice is depicted in Figure 1.

Figure 1.

Translating the language of the reforms.

Like the facilitator, teachers indicated that science was based on “data” and “evidence,” versus referencing the “empirical basis of science.” Table 2 provides the age-appropriate wording teachers used to communicate to students the aspects of NOS they had learned through the professional development.

Table 2. Teachers' Translation of the Reforms
Aspect of NOSKid-Friendly Terms
EmpiricalScientists collect data and use evidence to explain their ideas
TentativeScientists can change their ideas
SubjectiveScientists use their personal perspectives when they think about their problems and data
Creative/imaginativeScientists create new ideas
Observation/inferenceScientists interpret their observations and make inferences about them

These alternative descriptors for the aspects of NOS were displayed in teachers' classrooms on a set of posters they designed. These posters then became the basis for fostering explicit discourse about NOS throughout their science lessons. While the posters served as a benchmark for assessing student learning about NOS, teachers typically used this as an informal means for gauging student understanding. As teachers noted in a focus-group session with teachers held at the conclusion of the program:

Researcher: How much do you feel your students have understood about the nature of science and how do you know?

Jennifer: It's hard to tell in some ways, because it's not something you can assess very easily …I mean, through discussion I hear them using the language more, I see them—I mean, the language is also up on the wall—and I see them kind of using that, or …whenever we do science, their attention—they look up there …in that sense, they have a better understanding.

Cameron: Well, and sometimes, even when we're doing something else they will bring it up or they will tie it in with something that they learned. I'm always really pleased, and maybe even a little surprised—

Kayla: –that they're making a connection.

Cameron: Yeah! And I feel like as the year has progressed, that's definitely happened for some of the kids. I still have children who go off on tangents or aren't quite grasping things, but there are a lot of kids I think are getting a grasp of what it's about—the things we've done this year. [Transcript 5.13]

Operationally Defining NOS in the Context of Inquiry

Inquiry, which was a dual focus of the professional development program, was an important part of teachers' classroom practice as it provided them a venue for emphasizing the various aspects of NOS explicitly. Teachers fostered discourse about NOS through debriefing sessions following student investigations, by asking students to reflect on their own inquiry experiences and draw parallels between their work and the work of scientists. As the teachers described in their presentation at the annual meeting of the state science teachers' association, they had focused the wording of their posters on “what scientists do.” Displayed throughout the year in teachers' classrooms, the posters became a tool for making various aspects of NOS explicit and to help students operationally define NOS in the context of inquiry. In other words, teachers used the posters to help students deepen understanding of their own knowledge construction in science class and link this to the broader scientific enterprise. For example, following a field trip to the NASA Challenger Center, Kayla's students created Venn diagrams that compared their actions during the mission simulation to the work of scientists. As Kayla explained, this consisted of

Talking about what scientists do, how different scientists use different things—things that kids can relate to. I also think it's more—talking about science in different areas than here's what we're doing, here's the unit, here's an activity.

Cameron and Jennifer similarly held such debriefing sessions at the end of science lessons, focusing on the question “How is what you did [in this lesson] like what scientists do?” For example, Cameron used formative assessment through the open-ended question to identify students' prior knowledge about force and motion and guide her instruction. For example, she began a subsequent lesson on “pushes and pulls” from her curriculum with a class discussion during which she raised the question, “How do we make things move?” She recorded the students' responses on chart paper so they could revisit their ideas after the investigation. She also concluded her lesson with an explicit debrief regarding the empirical NOS by asking students to think about what they had done in the context of scientists' work (Akerson & Hanuscin, 2007).

Of course, it should be noted that teachers had spent a significant amount of time over the 3 years of the project adapting their curriculum materials and de-cookbooking science activities to make them more reflective of NOS and scientific inquiry. The way in which teachers drew on their more general pedagogical knowledge (PK) to do so it depicted in Figure 2.

Figure 2.

Emphasizing NOS in the context of inquiry.

Had teachers not adapted their curricula, it is unlikely that debriefing would have provided opportunities for students to draw appropriate parallels between their own activities in the lessons and the activities of science. As Sandoval emphasizes, “school science [is often] so unlike professional science that we have no real hope to expect that students would develop robust epistemologies of science” (2005, p. 12). Thus, teachers' knowledge of inquiry pedagogy and ability to create an inquiry-based classroom were essential to their teaching of NOS. Nonetheless, inquiry was not the only instructional context in which teachers explicitly focused on NOS. Children's literature provided another fruitful venue through which teachers engaged students in discourse about the work of scientists.

Drawing Analogies to NOS Using Children's Literature

In addition to building connections between students' classroom inquiry and NOS, teachers used children's literature to introduce students to ideas about NOS (Figure 3).

Figure 3.

Using children's literature to draw analogies to NOS ideas.

By calling attention to aspects such as subjectivity (or, as teachers put it, the personal perspectives) in the context of familiar stories, teachers were able to assist students in recognizing these same qualities in scientific work. For example, Cameron utilized Seven Blind Mice (Young, 1992) to help students understand the subjective NOS. In this story, seven blind mice each feel a part of an unidentified object, but come away with a different idea about what the thing is (an elephant):

After reading the book, Cameron followed up by drawing students' attention to the subjective NOS. She began by talking about the background knowledge the white mouse had after he heard the other mice's observations and inferences about the “unknown thing.” She asked, How is this like what scientists do? Do scientists ever talk to other scientists? Do you think they share ideas and do you think by sharing their ideas with each other they are influencing each other's interpretations? [Fieldnotes 5.12]

It is important to note here that a prominent feature of Cameron's science instruction involved students sharing their ideas with her and with each other. Cameron would often refer students back to this story as they debriefed subsequent science activities. Thus, while the use of children's literature was a more content-generic approach to teach aspects of NOS, the experiences provided a basis for connecting to NOS while learning content.

The following fall, Cameron again used the book with her kindergarten students, to make this aspect of NOS explicit by drawing an analogy between the actions of the mice in figuring out the “unknown thing” and what scientists do. When she asked whether scientists always agree with one another, several eager students shouted “No!”

Cameron: [responding to these students] You think they don't. They don't really think the same thing all the time? [Redirecting her question to the whole class] Do you think they always agree all the time?

Students: No.

Cameron: No. [nodding in agreement with the class] Because everybody is different and everybody thinks different. They are exploring looking for things. One scientist thinks different than the others. Just like how the mice did. Each mouse came back with different feeling. One of them said it was a fan and other said it was a rope. They all came back with different ideas. And do you think this happens to the scientist?

Students: Yes. [Transcript 11.22]

Because the students could recognize the different perspectives of the mice in this situation, Cameron believed this would facilitate student thinking about how scientists' different perspectives play a role in formulating ideas in science. In this particular excerpt Cameron enacts what could be considered a more didactic approach and could have, as an alternative, asked students to explain why they think scientists disagree versus providing an explanation herself. Nonetheless, it illustrates her selection of what she feels is an appropriate example of subjectivity to which her students can relate. As Bartholomew et al. have emphasized, “Many of the ideas embedded in an understanding of the nature of science are difficult to formulate in clearly teachable propositions” (2004, p. 268). Cameron's relativistic portrayal of subjectivity in the example above illustrates this difficulty and the potential for ideas about NOS to be “lost in translation” when simplifying ideas for young learners.

Jennifer also utilized the children's literature selections from the workshops to help her students understand the creative and subjective NOS. As she explained,

Actually, “personal perspectives” I've emphasized a lot this year—and I think I mentioned, we started out using that Professor Xargle book …. Just how something is described …it can depend on your experience with it …pointing out that names and titles and things are human-derived, and they're not just “there” [Transcript 5.13]

Jennifer asked students to consider why the ideas Professor Xargle (an alien visitor to Earth) may have formed what we would consider to be incorrect inferences regarding his observations of humans engaged in everyday activities. Students quickly recognized that Professor Xargle had a different perspective, not having grown up on Earth. In subsequent lessons in her classroom, Jennifer drew an analogy between Professor Xargle's (Willis, 1989) formation of inferences based on his observations to students' own observations and inferences, and the prior knowledge they had. At the conclusion of the lesson, she had students debrief the experience by making T-charts of their observations and inferences to highlight a distinction between the two.

Unlike Cameron and Jennifer, Kayla did not use children's literature to engage her students in discourse about NOS. When asked about this, Kayla said, “If you're wanting to get students talking about NOS specifically, none of the science books I've looked at have talked about the nature of science” [Transcript 12.6]. Unlike Jennifer and Cameron, Kayla was teaching upper-elementary students, and relied more on chapter books in her teaching, versus the kind of picture books utilized to model this strategy in the workshops. The literature selections utilized in the primary teachers' lesson could certainly have been used with upper-elementary students (indeed we have used children's literature to teach teachers about NOS), and so this finding may perhaps reflect Kayla's inexperience using literature to teach science, more generally. For example, prior to the program both Cameron and Jennifer reported using children's literature often with their students during science lessons, whereas Kayla did not.

Teachers' PCK for NOS

The three ways in which teachers transformed their understanding of NOS into forms accessible to students provide rich accounts of their PCK in action. Figure 4 synthesizes the way in which teachers drew on their SMK, general PK, and knowledge of their context, as well as the interactions between the various knowledge bases that are integrated in the enactment of their PCK. In this figure, we have foregrounded particular aspects of teachers' PCK that were more developed (e.g., instructional strategies) and used solid arrows to indicate the paths the various knowledge bases on which teachers drew most heavily. Dashed lines indicate a path or influence that was not fully utilized as teachers enacted their PCK for NOS (e.g., the feedback loop between instruction and assessment).

Figure 4.

Teachers' PCK for NOS.

Orientations Toward Teaching Science

Orientations, or the knowledge and beliefs teachers have about the purposes and goals for teaching science at a particular grade level, guide teachers' decision making in the classroom. As Volkmann and Zgagacz (2004) indicate, a teacher's fundamental beliefs about NOS support certain orientations. In our program, teachers initially possessed activity orientations (Akerson & Hanuscin, 2007), but through the professional development had developed an inquiry orientation—that is, they began to represent science as inquiry in their classrooms and emphasize what scientists do. Their instruction focused on the goal of providing experiences for students that reflect science as it is practiced in the “real world.” This is consistent with Abell's (2007) review of the research on teacher knowledge, in that orientations can change over time. However, the author also points out that while research suggests orientations influence teacher learning and practice, that influence may not be direct. Furthermore, orientations can be context specific. In the case of our teachers, they simultaneously learned about NOS and inquiry. Our data suggest that this dual focus contributed to compatibility between teachers' orientations and their teaching of NOS.

Knowledge of Curriculum

Teachers' classroom practices reveal they drew little upon their knowledge of curricula specifically for NOS—however, this appeared to be more a matter of a lack of availability of specific curricular materials and programs to address NOS, versus deficiency in teachers' knowledge of such materials. Abd-El-Khalick et al. (1998) described how participants needed “more activities in before they could adequately teach NOS” (p. 429), suggesting that lack of appropriate curricula may constrain teachers' ability to teach NOS. The three teachers in our study similarly expressed a desire for additional lessons and activities to use with their students; however, they were not were not dissuaded from teaching NOS by a lack of available curricula. For example, the district-adopted curriculum teachers were provided did not include an explicit emphasis on NOS; as a result, teachers requested time and support to adapt their curriculum materials to teach NOS. Their teaching context provided them with the autonomy to do so; they were not mandated a highly scripted curriculum to follow, but rather were entrusted with the responsibility of using the curriculum flexibly as a tool. By drawing on their knowledge of instructional strategies, specifically the explicit-and-reflective instruction learned in the PD, and knowledge of their students (specifically, age-appropriate terminology to use) teachers were able to embed a focus on NOS within their curriculum.

Knowledge of Instructional Strategies

Magnusson et al. distinguish between subject-specific strategies, which are more general approaches for teaching science, and topic-specific strategies, which include both representations and activities to help students comprehend specific ideas and concepts. Our professional development program was mainly focused on this aspect of teachers' PCK—in terms of helping them develop strategies for teaching NOS that were explicit and reflective. In addition, we focused on more subject-specific strategies such as inquiry. Our findings illustrate that teachers were able to implement these strategies as modeled for them but also improvise and develop their own unique strategies for embedding NOS into their teaching. For example, teachers made decisions about when and how to emphasize NOS within the context of student inquiries—identifying aspects of NOS that were inherent in the lesson, and asking students to relate these to “what scientists do.” Identification of these opportunities hinged on their own understanding of NOS, as well as their ability to design learning experiences that engage students in ways that reflect NOS. In other words, their SMK mediated their choice and implementation of instructional strategies.

Inquiry was not the only context in which teachers focused on NOS, however. For example, two of our teachers, drawing on their more general PK related to using children's literature, were able to emphasize NOS. By introducing more common situations in which different observers reached different conclusions, for example, teachers aimed to help students recognize subjectivity, or the way in which scientists' “personal perspectives” influence their ideas. These analogies were intended to make ideas about NOS more accessible to their young learners.

Knowledge of Assessment

Knowing what to assess, as well as how to assess, is an important part of PCK. While each of the teachers in our study developed a unique repertoire of instructional strategies to teach their students about NOS, it became clear during our secondary analysis that they did not have a similar repertoire for assessing students' ideas of NOS. This was not because they did not view NOS as important for students to understand, but rather they had insufficient knowledge of assessment specific to this topic. For example, teachers' comments about the difficulty of assessing students' views of NOS point out their difficulty in knowing what to assess. This is significant, because teachers' ability to assess their students' views of NOS can limit the degree to which they can evaluate their own effectiveness. Without this source of feedback, it would be unlikely that they would be able to make continued improvement in their abilities to teach NOS, as well as their ability to identify and address the specific views and difficulties of their students.

The type of reflective debriefing teachers conducted in the context of literature experiences and following classroom investigations did, indeed, promote students' understanding of NOS. However, teachers' use of these discussions as informal assessment strategies provided them with only a general sense of what their students understood about NOS, versus an understanding of specific student ideas and areas of difficulty. Teachers trusted they were learning appropriate instructional strategies in the workshops and assumed these to be effective. What became evident in our reexamination of the data is that, while teachers had a growing sense their students were “making connections,” they had ultimately relied on the results of our research assessments as evidence of the impact of their instruction on their students' ideas about NOS. What is noticeably absent from teachers' practice is the use of formal and/or summative assessment strategies to determine NOS learning outcomes of individual students. We noted, however, that teachers used such assessments to determine learning outcomes related to students' understanding of other science topics. Thus, while they had more general knowledge of assessment that they drew on to assess students' ideas about other content, they had not developed topic-specific strategies for assessing students' ideas about NOS.

Knowledge of Learners

In Magnusson et al.'s model for PCK, knowledge of learners consists of two categories of knowledge: that of requirements for learning and that of areas of student difficulty. In transforming NOS into forms accessible to their students, our teachers drew on their more general knowledge of their students' abilities, as well as anticipated areas of difficulty, as shown in the example of translating language of the reforms into grade-appropriate terminology. However, as discussed above, without effective strategies for assessing student ideas, it is unlikely that teachers would be able to identify the specific areas of difficulty their students encountered when learning about NOS. Indeed, while teachers felt their students were “making connections,” noticeably absent from the data are discussions of difficulties teachers faced in helping students understand particular ideas about NOS, or misconceptions about NOS they encountered in their classrooms.

DISCUSSION AND IMPLICATIONS

New Insights Arising From This Study

This study was conceptually grounded in the five components of PCK (Magnusson et al., 1999). Our empirical research supports the applicability of this model to characterize and examine teachers' PCK for NOS. In particular, our study illustrates how this model can be used to develop a more holistic view of teachers' classroom practices related to NOS, including teachers' use of assessment. While teachers were able to successfully enact explicit-and-reflective instructional strategies to teach NOS, they did not specifically assess the impact of that instruction on their students' understanding of NOS. Prior research has attributed teachers' failure to assess their students' ideas about NOS to a “discrepancy between [their practices and] stated belief in the importance of teaching NOS” (Abd-El-Khalick et al., 1998, p. 427). Our study provides an alternative explanation, namely that teachers may lack sufficient knowledge of strategies for assessing students' ideas about NOS. While the teachers in our study had a general sense that their students were “making connections,” they also indicated that NOS was not something that could be easily assessed. That is, they were unfamiliar with appropriate means through which they could determine their students' ideas. These findings align with prior research by Magnusson et al. (1999) that suggests the development of teachers' PCK may be uneven, in that changes in knowledge of one component (e.g., knowledge of instructional strategies) may not be accompanied by changes in other components (e.g., knowledge of assessment). Through participation in the professional development program, our teachers had developed knowledge of instructional strategies for teaching NOS, but not the complementary knowledge of assessment.

As Abell (2007) points out, while research has shown that teachers, overall, lack knowledge of students science conceptions, this knowledge improves with teaching experience. Nonetheless, it stands to reason that teachers' knowledge of assessment might serve as a limiting factor in developing their knowledge of learners. Given the integrated nature of PCK, insufficient development of one component knowledge base can have consequences for enactment of teachers' PCK. For example, without well-developed knowledge of assessment of NOS, the three teachers lack an important source of feedback to inform their instruction. Fortunately for their students, their instructional practices were effective in helping students improve their understanding of NOS. However, the teachers did not possess the knowledge and skills for assessing NOS to determine this on their own; rather, they had relied on the results of our research assessments as evidence that their instruction was effective. Had this data not been available to them, and had their instruction not been effective, it is likely they would have continued unaware. Indeed, it has been reported in several studies that teachers may indeed believe that they are teaching NOS when they are not doing so explicitly (Akerson & Abd-El-Khalick, 2003; Bartholomew et al., 2004; Schwartz & Lederman, 2002). Teachers' beliefs were based on their own actions (i.e., what they did that they considered to constitute teaching NOS), rather than assessment of the impact of their instruction on students' learning. It stands to reason that well-designed classroom assessments could provide the necessary evidence for teachers to realize whether their instruction is effective in addressing students' ideas about NOS. As Schwartz and Lederman emphasize, “student achievement may and should then affect the teacher and subsequent actions” (2002, p. 233). That is, teachers ideally would modify their instruction in light of these assessments. In this manner, the further development of teachers' PCK could be supported as they learn from their practice. Our recent work has shown that through professional development teachers can, and do, develop formal, nontraditional assessments for their students' NOS conceptions (Akerson, Cullen, & Hanson, 2009).

Our work lends further support to the proposition that teacher knowledge builds from more generalized PK and isolated bits of PCK and moves toward PCK that is more integrative and transformative (Friedrichsen et al., 2007; Wang & Volkmann, 2007). For example, drawing on more general PK (e.g., ways of using children's literature) proved fruitful in helping two of our teachers emphasize NOS explicitly in their teaching. Similarly, utilizing inquiry as a teaching strategy enabled all three teachers to make explicit connections to NOS. This suggests that professional developers can capitalize on teachers' existing strengths and instructional strategies to develop their PCK for a new topic, such as NOS; conversely, this means that professional developers should be aware of the possibility that teachers may lack more general PK that could enable them to teach NOS successfully.

Clearly, helping teachers teach NOS effectively is a difficult and complex task for teacher educators. By utilizing PCK as a lens to understand teachers' classroom practice, we were able to identify important gaps in teachers' knowledge—gaps that could remain undetected by focusing more narrowly on teachers' use of instructional strategies and the impact on student learning. In turn, we were provided critical insights that led us to reflect on the design of professional development and how it might better address such gaps in teachers' knowledge. As Magnusson et al. emphasize, “teacher educators should be aware of the possibility that teachers may not have requisite knowledge of components not addressed by the program that would help them effectively use the knowledge they develop from the program” (1999, p. 126). On the basis of our findings, we recognize that professional development efforts could be enhanced by expanding the focus to help teachers develop other aspects of their PCK for NOS, rather than focusing solely on helping teachers develop their skills for particular instructional strategies. For example, equipping teachers with classroom-based assessment strategies for NOS might help them recognize whether learning is occurring, identify specific areas of difficulty students have in understanding NOS, and in turn develop their knowledge of learners. Consistent with this, we assert that research on teachers' classroom practices in relation to NOS must necessarily go beyond examination of instruction to consider the important feedback loop that exists between teachers' instruction and assessment. Such studies would shed light on how teachers develop their PCK for NOS through practice.

Supporting the Development of Teachers' PCK for NOS

Schwartz and Lederman (2002) provided the beginning teachers in their study with an “activity pack” of NOS lessons that they had experienced, as learners, during their teacher education courses. Schwartz and Lederman later observed that teachers relied on these alone in their instruction. In contrast, though the pedagogical repertoire of our three teachers was based on explicit-and-reflective activities modeled for them in their professional development program, we found they applied explicit-and-reflective strategies in novel ways in the context of inquiry-based lessons, literacy experiences, and field trips that they planned for their students. Despite this, however, our teachers continued to request additional “NOS lessons” to implement in their classrooms. Appleton (2006) similarly described elementary teachers' desire for prepackaged “activities that work” and suggests that, indeed, these may play an important role in the development of elementary teachers' PCK for teaching science. A review of elementary science curricula shows that such curricula do not suggest how to embed NOS within the content, therefore teachers need assistance to integrate NOS into their own science teaching (Akerson, Hanson, & Cullen, 2007). While we agree with Schwartz and Lederman that effective professional development should avoid providing “cookbook” NOS lessons for teachers to implement, we also concur with Appleton that some level of support is needed to help teachers develop their pedagogical repertoire and abilities to teach and assess NOS. Professional developers need to provide scaffolds to teachers in terms of both instructional and assessment strategies until they have developed sufficient PCK to create or revise their own lessons.

Our findings highlight a need for “educative curriculum materials” for NOS, or K-12 curriculum materials that are intended to promote teacher learning in addition to student learning (Davis & Krajcik, 2005). Educative curriculum materials can help teachers add important ideas to their repertoires, including SMK of NOS and students' likely ideas; however, such materials should remain flexible in promoting teachers' pedagogical design capacity, or their ability to use personal resources and supports embedded within curriculum materials to adapt curricula to meet the needs, interests, and abilities of their students. In this manner, we believe educative curriculum materials might help address the tension between teachers' desire for prepackaged NOS “activities that work” and professional developers' desire to avoid providing a “bag of tricks.”

Educative curriculum materials for NOS would go beyond the types of resources that currently exist such as collections of activities and pedagogical strategies for teaching NOS (e.g., Bell, 2008) or syntheses of research on effective teaching of NOS in practitioner journals (Hanuscin & Lee, 2009). For example, educative curriculum materials would help teachers develop strategies for both formatively and summatively assessing students' ideas of NOS. Knowledge of assessment strategies forms an important component of teachers' PCK and provides crucial feedback to teachers about the effectiveness of their teaching, which in turn allows them to adjust and respond to students' understanding. As emphasized in the National Science Teachers Association Standards for Science Teacher Preparation (NSTA, 2003) teachers should use assessment to guide and modify instruction. Furthermore, they should be able to “demonstrate that they are effective by successfully engaging students in the study of the nature of science” and that “assessments of effectiveness must include at least some demonstrably positive student outcomes” (NSTA, 2003, p. 17). As emphasized by Davis and Krajcik (2005), educative curriculum materials would provide support for PCK by helping teachers anticipate common student misconceptions, as well as understand reasons why students might hold these ideas. In turn, educative curriculum materials would also provide suggestions to help teachers challenge students' thinking through analogies and alternative ways of representing ideas. Through dynamic interactions between teacher and curriculum, both would be transformed. While professional development workshops, courses, and professional readings can serve as sources of input to PCK, it is in action that teachers' PCK takes form and is shaped. Equipping teachers with the necessary knowledge of assessment to close the feedback loop between teaching and learning can contribute to further development of their PCK. Similarly, educative curriculum materials that support teachers in learning through their practice can play an important role in this process.

  • 1

    Pseudonym has been used for the professional development program.

  • 2

    Pseudonym has been used for the elementary school.

  • 3

    Pseudonyms have been used for all participants.

Ancillary