Closing the gap between beliefs and practice: Change of pre-service chemistry teachers' orientations during a PCK-based NOS course

Abstract

The purpose of this case study was to investigate how pre-service chemistry teachers' science teaching orientations change during a two-semester intervention designed to enhance their pedagogical content knowledge (PCK) for teaching the nature of science (NOS). Moreover, the way that pre-service chemistry teachers translated their change in orientation into both their instructional planning and their PCK was examined. Thirty pre-service chemistry teachers enrolled in a Research in Science Education course participated in the study. Responses to an open-ended instrument, interviews, observations, and documents such as lesson plans and reflection papers were used as qualitative data sources. Through in-depth analysis of explicit PCK and further deductive analysis, we identified the influence of the intervention on participants' orientation and how participants translated their orientation into their planning and PCK. Analysis of data revealed that most of the pre-service teachers' naïve and transitional views about NOS changed into informed ideas after explicit-reflective NOS instruction. Participants revised their science teaching orientations by including more reform-based orientations at the end of the course (i.e., teaching NOS-related orientations). Their plans included at least one NOS aspect as an objective, which indicates that all of the participants designed their lesson plans with more informed views about at least one NOS aspect. In terms of aligning their reform-based orientations with other PCK components, pre-service chemistry teachers were more able to align their orientation with knowledge of instructional strategy and assessment than with knowledge of the learner. Implications for science teacher education and research are discussed.

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Introduction

“I will not be a scientist—why am I learning nature of science?”

– Linda, pre-service chemistry teacher, Reflection Paper [01.14.2013]

Linda's reflection above is indicative of the challenge that we face as teacher educators in preparing prospective teachers to address this aspect of the reforms. Belief in the importance of teaching the nature of science (NOS) as a cognitive learning outcome is closely related to the extent to which a teacher may attempt to teach NOS (Abd-El-Khalick et al., 1998; Bell et al., 2000). Scientific literacy has been a major focus of reform documents and has formed the mission of science curriculums around the world (American Association for the Advancement of Science [AAAS], 1993; Dillon, 2009; Next Generation Science Standards [NGSS], 2013). Scientifically literate individuals should not only know scientific concepts but also understand NOS. Understanding NOS enables individuals to understand socio-scientific issues and hence participate in decision-making processes (Driver et al., 1996). However, science teachers' beliefs about science teaching and learning should be considered first if they are expected to implement reform goals in their classroom (Bryan and Abell, 1999).

Friedrichsen et al. (2011) re-conceptualized science teaching orientation as a result of their extensive review of literature on teachers' beliefs. They define it as consisting of interrelated sets of beliefs that teachers hold in regard to the goals or purposes of science teaching, NOS, and science learning. The literature also provided evidence for the “dimensions of belief” system proposed by Friedrichsen et al. (2011) (Boz and Uzuntiryaki, 2006; Friedrichsen et al., 2011; Park and Chen, 2012). For clarity, science teaching orientation will be used to refer teachers' beliefs in this study.

Science teaching orientations are resistant to change; teacher educators must create conceptual changes in their orientations if they hope to align teachers' orientations with reform-based goals (Koballa et al., 2005). In addition, teachers' knowledge and belief systems are tacit in nature (Loughran et al., 2004). Therefore, teachers should reflect on their orientations (Boz and Uzuntiryaki, 2006; Jones and Carter, 2007). Since science teaching orientation is an overarching component of pedagogical content knowledge (PCK) (Magnusson et al., 1999), PCK should be used as an explicit framework in teacher education courses. Bringing all these recommendations together, we designed a PCK-based NOS course and investigated how pre-service chemistry teachers' science teaching orientations changed during this course. We were also interested in how pre-service teachers translated this change into their instructional plan and their PCK.

We recognize that pre-service teachers have relatively undeveloped PCK (van Driel et al., 1998), but pre-service teachers' PCK may be considered “PCK readiness” (Davis, 2003; Smithey, 2003). PCK readiness enables pre-service teachers to know, apply, and—to some extent—integrate components of PCK. These steps are valuable in developing rich and usable PCK (Smithey, 2003).

Theoretical framework

Nature of science

NOS refers to the epistemology and sociology of science: science as a way of knowing, or the values and beliefs inherent to scientific knowledge and its development (Lederman, 1992). NOS is a fertile hybrid arena including philosophy, history, sociology, and psychology of science. It is the pursuit of answering complicated questions: What is science? How is it done? What is the nature of scientific knowledge? How is science perceived by society and how has it operated throughout history? What are the characteristics of scientists? Who are scientists? How do scientists work? (McComas and Olson, 1998). Although some may criticize the fact that understanding scientific inquiry is not considered in NOS (Irzık and Nola, 2011), a comprehensive and deliberate understanding of NOS not only includes an understanding of the nature of scientific knowledge but also of scientific enterprise or practices (Meichtry, 1993). The inclusion of knowledge about scientific practices is also emphasized by recent reform documents (NGSS, 2013), as is research on the epistemology of science. General epistemological commitments include beliefs about what counts as scientific knowledge and how such knowledge is acquired and justified (Smith et al., 2000; Sandoval and Reiser, 2004). Bearing in mind that NOS is not the same as scientific inquiry (Lederman et al., 2014), in this study, NOS is defined as epistemology of scientific knowledge (i.e., NOS in literature) and scientific practices (i.e., nature of scientific inquiry in literature [NOSI]) (Sandoval, 2005, 2014; Irzık and Nola, 2011; NGSS, 2013; Lederman et al., 2014).

There has been an ongoing debate among philosophers of science and science educators (e.g., Alters, 1997; Smith et al., 1997; Irzık and Nola, 2011; Abd-El-Khalick, 2013) about the specific definition of NOS and what level of NOS understanding should be communicated to students. However, students and teachers are not expected to understand the scientific endeavour from a philosophical point of view (Smith and Scharmann, 1999), given that even scientists themselves do not need that information. Learners of NOS should convey simply “a more complex understanding of science, not a total or even a very complex understanding” [emphasis mine] (Matthews, 1998, p. 168). The science education community has achieved a certain degree of consensus on what this complex understanding of NOS includes for students from kindergarten to 12th grade (K-12) (Niaz, 2009; Abd-El-Khalick, 2013). Although it's more simplistic than a philosophical stance to science, this complex understanding goes beyond what is currently emphasized in science textbooks (Abd-El-Khalick et al., 2008), taught by the majority of science teachers (Abd-El-Khalick and BouJaoude, 1997), and understood by students (Dogan and Abd-El-Khalick, 2008).

In this study, we defined NOS using a set of characteristics common to reform documents and believed to be relevant and accessible to K-12 students (see Table 1) (Abd-El-Khalick, 2012; NGSS, 2013; Erduran and Dagher, 2014; Lederman et al., 2014). These statements are not merely declarative statements about science that students should memorize; rather students can conceptualize these aspects by analysing examples from science, and explain how these aspects relate to one another in terms of scientific practices (Ozgelen et al., 2013). Some may argue that the list is too general or broad and does not sufficiently capture the complexities of various disciplines in science (e.g., Cetin et al., 2010; Irzık and Nola, 2011). However, these researchers have not indicated how these aspects are irrelevant to specific science disciplines, such as chemistry, or provided domain-specific NOS aspects with regards to the various disciplines in science (e.g., nature of chemistry). Also, the level of generality in the NOS aspects in Table 1 could help pre-service teachers to teach NOS to their students in a way that is “…non-controversial, but genuinely more informed than the currently prevalent naive conceptions” (Abd-El-Khalick, 2012, p. 360).

Table 1 Aspects that constituted NOS understanding in this study

NOS aspects	Explanation
Scientific knowledge is tentative	Although scientific knowledge is durable, it changes with new data or reinterpretations of existing ones. This change might be a complete (e.g., phlogiston theory vs. oxygen theory) or partial change (e.g., atom theories).
Science is based on observations and experiment	Scientists use observations and experiments when appropriate to test the validity of their claims. Not every scientific discipline enables scientists to conduct experiments, such as astronomy, and not all scientific knowledge is constructed as a result of experiments, such as evolution theory.
Scientific knowledge is based on inferences as well as observations	Scientific knowledge consists of the inferences derived from observations. Observations are descriptive statements about phenomena obtained by using senses (e.g., sight and hearing) or some technological device (e.g., using a scale to measure mass). However, inferences are the interpretations of these observations (e.g., Rutherford's atom model).
Scientific theories and laws have different roles in science	Scientific theories and laws have different meanings and roles in science. Scientific laws are descriptive statements about the perceived relationships, regularities, patterns, and generalizations in nature (e.g., Boyle's law). On the other hand, scientific theories are the explanations for phenomena or laws (e.g., kinetic molecular theory).
Scientific knowledge is theory-laden and includes subjectivity	When scientists develop questions, design investigations, and make observations and inferences, their previous knowledge, experiences, and expectations, and the theories and laws that they believe, unavoidably affect them.
Creativity and imagination play a major role in science	Logic by itself is not sufficient for science. Creativity and imagination are required during various phases of a scientific study, such as constructing hypotheses, designing different methods for observation and experiments, and final interpretation of data.
Social and cultural factors affect science	Politics, religion, philosophy, economy, and moral values are some of the factors that influence deciding what and how science is conducted, interpreted, and developed. In addition, scientific knowledge is produced, presented, and evaluated in social contexts including groups of scientists and scientific organizations.
Science and technology are not the same thing	Science and technology are different from each other with regard to their purposes, methods, and products. The purpose of science is to explain the natural world while technology seeks solutions for human problems and tries to make life easier. Scientists use scientific inquiry methods, while technicians use problem-solving strategies such as technological design and constructs. Scientific knowledge is the product of science and designs are products of technology. More importantly, technology is not the application of science.
There is no universal step-by-step scientific method	There are several common scientific processes—such as forming hypotheses, observation, experimentation, interpretation, and hypothesis testing—but these processes do not have to follow a specified order (e.g., Darwin proposed the theory of evolution right after his observations in the Galapagos Islands without forming an a priori hypothesis).
Serendipity plays a role in science	Chance (i.e., discovery as a result of unexpected situations) has played an important role in some scientific discoveries, such as X-rays. Just chance is not enough for a scientist to discover new phenomena. Scientists paid attention to unexpected events, interpreted them through logic, and, as a result, produced scientific knowledge different to that which they intended to investigate.

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Pedagogical content knowledge

PCK was first conceptualized by Shulman (1986) and is known as the pedagogical professional knowledge base for teachers (Shulman, 1986, 1987; Abell, 2007; Gess-Newsome, 2015). Magnusson et al.'s PCK model (1999) was utilized for both designing the PCK-based NOS course and examining how teachers' orientations changed during the course for two reasons. First, there has been empirical support for the utilization of this model for several topics, including NOS (e.g., Hanuscin et al., 2011; Park and Chen, 2012; Aydin et al., 2013; Demirdöğen et al., 2015). Second, Magnusson et al.'s (1999) PCK is a recognized theoretical framework that enables researchers to capture teachers' knowledge of teaching (Abell, 2008).

PCK has been used as a theoretical construct to investigate and define teachers' NOS teaching practices (Schwartz and Lederman, 2002; Hanuscin et al., 2011; Abd-El-Khalick, 2013; Hanuscin, 2013). PCK for NOS can be defined as a knowledge base that “…would enable the teacher to organize, represent, and present the topic for instruction in a manner that makes target aspects of NOS accessible to precollege students” (Abd-El-Khalick and Lederman, 2000a, p. 692). With the recognition of PCK in research on teaching NOS literature, some researchers have developed their own PCK models for NOS (e.g., Abd-El-Khalick, 2013) and others used existing PCK models (i.e., Magnusson et al., 1999) (e.g., Faikhamta, 2013; Demirdöğen et al., 2015). Although these various conceptualizations of PCK might be perceived as different, they all share elements of the PCK model proposed by Magnusson et al. (1999): science teaching orientation, knowledge of the curriculum, knowledge of the learner, knowledge of instructional strategy, and knowledge of assessment.

Science teaching orientation (STO) is a teacher's knowledge and beliefs about the purposes and goals of teaching science at a particular grade level (e.g., NOS). Knowledge and beliefs about science curriculum (KoC) includes teachers' knowledge about the objectives related to the science topic they are teaching in the curriculum and curricular materials for teaching the topic. Knowledge and beliefs about learners' understanding of specific science topics (KoL) refers to teachers' knowledge about the requirements for learning specific science concepts and the areas of science that students find difficult, including misconceptions. Teachers' knowledge and beliefs about assessment (KoA) in science comprise their knowledge of the dimensions of science learning that are important to assess (e.g., science concepts and scientific process skills) and knowledge of the methods by which learning can be assessed (e.g., concept maps and open-ended questions). Lastly, knowledge and beliefs about instructional strategies (KoIS) for teaching science is a teachers' knowledge and use of topic-specific activities (e.g., analogies and models) and subject-specific strategies (e.g., conceptual change and argumentation). Fig. 1 represents the conceptualization of Magnusson et al.'s PCK model (1999) from the perspective of NOS that was used during the course design and analysis of data.

Fig. 1 PCK for NOS model used in this study.

Several studies applying Magnusson et al.'s (1999) model to research PCK of NOS have provided evidence for the utility of this model as a lens for research on teaching NOS (Hanuscin et al., 2011; Faikhamta, 2013; Hanuscin, 2013; Demirdöğen et al., 2015). These studies investigated PCK for NOS in different contexts with different participants. Hanuscin et al. (2011) investigated the NOS-related classroom practices of elementary teachers who participated in a professional development program on developing teachers' NOS understanding. They successfully improved students' NOS understanding after the program. Later, Hanuscin (2013) examined critical incidents in the development of a prospective teacher's PCK for NOS. Other studies were similar in the sense that they used the PCK-based NOS course as the context of their study (Faikhamta, 2013; Demirdöğen et al., 2015). However, Faikhamta (2013) investigated in-service science teachers' NOS understanding and orientation, whereas Demirdöğen et al. (2015) examined pre-service chemistry teachers' NOS understanding and PCK components, and the relationship between NOS understanding and PCK for NOS. All these studies emphasized the need for more comprehensive teacher education and professional development programs that address all PCK subcomponents, rather than one component (e.g., instructional strategies for NOS). They also highlighted the demand for research on the interplay among PCK subcomponents. Existing literature on PCK for NOS adds to our understanding of teachers' instructional practices when teaching NOS and their related knowledge. However, belief in the importance of teaching NOS as a cognitive learning outcome is closely related to the extent to which a teacher may attempt to teach NOS (Abd-El-Khalick et al., 1998; Bell et al., 2000) and current literature lacks evidence on how teachers' beliefs—as indicated by their orientations—change to value NOS. Moreover, how this change translates into their planning and teaching is not well documented. Although Faikhamta (2013) investigated change in teachers' orientations, the study did not indicate how teachers reflect this change in their instruction or other PCK components. Therefore, in the present study we were also concerned with how teachers translated the change in their orientation to both their instructional planning and other components of PCK.

Science teaching orientation

Orientation was not the universally agreed-upon term by researchers who propose PCK models until the work of Magnusson et al. (1999). Various terms have been used: conceptions of purposes for teaching subject matter (Grossman, 1990), purposes for math instruction (Marks, 1990), educational goals and purposes (Cochran et al., 1991), and teaching purposes (Fernandez-Balboa and Stiehl, 1995). Although phrased differently, all of these terms were used to refer to teachers' knowledge and beliefs about the purposes and goals for teaching science at a particular grade level. Magnusson et al. (1999) specifically defined nine orientations that a teacher might have: didactic, academic rigor, process, activity-driven, discovery, conceptual change, project-based science, inquiry, and guided inquiry. When defining each orientation they explained the goal of teaching science and the characteristics of instruction for that orientation. For instance, the goal of a teacher with a didactic orientation is to “transmit the facts of science” (Magnusson et al., 1999, p. 100). Instruction for this orientation is characterized as follows: “The teacher presents information, generally through lecture or discussion, and questions directed to students are to hold them accountable for knowing the facts produced by science” (p. 101). Studies investigating PCK utilized these categorizations for orientation for a long time. The first study conceptualizing orientation as a multidimensional construct was conducted by Park and Oliver (2008). They proposed a hexagon model of PCK that includes teacher efficacy as a sixth component. Park and Oliver (2008) advocated that orientation consists of three sub-dimensions: beliefs about purposes of learning science, decision making in teaching, and beliefs about the NOS.

In 2011, Friedrichsen and her colleagues pointed out several problems with orientation. First, there are multiple definitions and unclear use of the term. Second, research on PCK ignores the relationship between orientation and other PCK components. Last, studies assign teachers to one of the nine orientations proposed by Magnusson et al. (1999) instead of trying to understand orientation's multidimensional nature. To provide a clearer picture for other researchers, Friedrichsen et al. (2011) proposed a multidimensional definition for orientation by building on the empirical work in the literature. They defined science teaching orientation as “…consisting of [an] interrelated set of beliefs that teachers hold in regard to the dimensions…; beliefs about the goals or purposes of science teaching, (the nature of) science, and science teaching and learning” (p. 372). Beliefs about the goals or purposes of science include answers to questions such as “Why do I teach science to students?” (e.g., everyday coping). Beliefs about NOS include teachers' understanding both the nature of scientific knowledge and scientific enterprise (Meichtry, 1993). Lastly, teachers' beliefs about science teaching and learning include their beliefs about the role of the teacher, the role of the learner, how students learn science, and how science can be taught. Friedrichsen and her colleagues' work on orientation stimulated more deliberate and theoretical attention to science teaching orientation (Avraamidou, 2013; Boesdorfer and Lorsbach, 2014; Campbell et al., 2014). Orientation was identified as one of the amplifiers that enable teachers to pass topic-specific professional knowledge through their own lenses in the recent PCK model (Gess-Newsome, 2015). Although the new model provided a brief example for orientation (e.g., orientation toward preferred instructional strategies, such as didactic) there was no explicit specific description of what orientation is.

Of the several definitions available in the literature, we preferred to use Friedrichsen et al.'s (2011) definition for orientation for three reasons. First, the definition has a multidimensional nature. Second, it refers to different facets of teacher beliefs and how these beliefs influence teachers' practice. Third, applicability of this definition for research on orientation has been evidenced in the literature (Avraamidou, 2013; Campbell et al., 2013, 2014; Boesdorfer and Lorsbach, 2014). In line with Friedrichsen et al.'s (2011) orientation definition, the curriculum emphases proposed by Roberts (1988) were used to define teachers' orientation in this study. He portrayed each emphasis in terms of underlying the views of science, the learner, the teacher, and society. More importantly, “One can see that this description includes elements of the nature of science, goals of science education, and views of teaching and learning” (Friedrichsen et al., 2011, p. 371). The seven curriculum emphases are defined with their related dimensions in Table 2.

Table 2 Curriculum emphases defined by Roberts (1988, 2007) and used as the coding scheme in this study

Curriculum emphasis	Definition	View of science	View of learner	View of teacher	View of society
Everyday coping	Students use science to comprehend everyday objects and events.	A meaning system necessary for understanding and therefore controlling everyday objects and events	Needs to master the best explanations available, competent explanation of natural events, and control of mechanical objects and affairs.	Someone who regularly explains natural and manmade objects and events by appropriate scientific principles.	Autonomous, knowledgeable individuals who can do mechanical things well, who are entrepreneurial, and who look after themselves, are highly valued members of the social order.
Structure of science	Students understand how science functions as an intellectual enterprise.	A conceptual system for explaining naturally occurring objects and events, which is cumulative and self-correcting.	One who needs an accurate understanding of how this powerful conceptual system works.	Comfortably analyses the subject matter as a conceptual system, understands it as such, and sees the viewpoint as important.	Society needs elite, philosophically informed scientists who really understand how that conceptual system works.
Science, technology, and decisions	Students understand the interrelationship between science, technology, and society and hence make informed decision-making about socio-scientific issues.	An expression of the wish to control the environment and ourselves, intimately related to technology and increasingly related to very significant societal issues.	Needs to become an intelligent, willing decision maker who understands the scientific basis for technology, and the practical basis for defensible decisions.	One who develops both knowledge of and commitment to the complex interrelationships relating to science, technology, and decisions.	Society needs to keep from destroying itself by developing in the general public (and the scientists as well) a sophisticated, operational view of the way decisions are made about science-based societal problems.
Scientific skill development	Students acquire conceptual and manipulative scientific process skills.	Consists of the outcome of the correct usage of certain physical and conceptual processes.	An increasingly competent performer with the process.	One who encourages learners to practice the processes in many different contexts of science subject matter.	Society needs people who approach problems with a successful arsenal of scientific tool skills.
Correct explanation	Students learn about the end of scientific inquiry, which are concepts, theories, laws, models etc. in a scientific discipline.	The best meaning system ever developed for getting at the truth about natural objects and events.	Someone whose preconceptions need to be replaced and corrected.	One responsible for identifying and correcting words and errors in student thinking.	Society needs true believers in the meaning system most appropriate for natural objects and events.
Self as explainer	Students understand their effort to explain phenomena by appreciating the conceptual underpinnings that influence scientists when they are in the process of developing an explanation.	A conceptual system whose development is influenced by the ideas of the times, the conceptual principles used, and the personal intent to explain.	One who needs the intellectual freedom gained by knowing as many of the influences on scientific thought as possible.	Someone deeply committed to the concept of liberal education as exposing the grounds for what we know.	Society needs members who have had a liberal education—that is, who know where knowledge comes from.
Solid foundation	Students use science to prepare them for the topics that they are going to learn next year	A vast and complex meaning system which takes many years to master.	An individual who wants and needs the whole of science, eventually.	One who is responsible for identifying the most capable potential scientists.	Society needs scientists.

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Literature review

Studies investigating orientation fall under four categories: (1) research focusing on the interplay between orientation and other PCK components, (2) research examining change in orientation, (3) research investigating the alignment between orientation and instructional practice, and (4) research exploring teachers' orientation as a multidimensional construct.

Studies in the first category tend to use Magnusson et al.'s (1999) framework to define orientation. These studies revealed the following findings related to the relationship between orientation and other PCK components: Orientation shapes what to teach (Padilla et al., 2008); there is consistency between orientation and knowledge of instructional strategy (Henze et al., 2008; Park and Oliver, 2008; Padilla and van Driel, 2011); orientation is linked to the knowledge of the learner (Padilla and van Driel, 2011; Aydın et al., 2015); a didactic orientation inhibits the interaction between instructional strategy and other PCK components (Park and Chen, 2012); and didactic orientation influences teachers' selection of instructional activities for remedying student misconceptions (Aydın and Boz, 2013).

Research in the second category used either Friedrichsen et al.'s (2011) definition or Magnusson et al.'s (1999) categorization for orientation. Studies using Friedrichsen et al.'s (2011) multidimensional definition investigated prospective elementary teachers' orientations, the experiences that affected their orientation development (Avraamidou, 2013), and the change in in-service science teachers' orientations during technology-enhanced professional development (Campbell et al., 2014). Faikhamta also focused on the change in teachers' orientation during a PCK-based NOS course using Magnusson et al.'s (1999) categorization. Studies in the third category examined the degree to which a chemistry teacher's instructional practice is aligned with his orientation as defined by Friedrichsen et al.'s (2011) definition (Boesdorfer and Lorsbach, 2014). Studies in the last category (Kind, 2016) investigated pre-service science teachers' science teaching orientations through content-specific vignettes and questionnaires before participation in a teacher education program. Kind (2016) examined pre-service teachers' beliefs about NOS and orientations using Magnusson et al.'s (1999) categorization.

The aforementioned research investigating orientation has contributed to our understanding of what orientation is and how it relates to other PCK components and to practice. However, most of the studies considered orientation as a one-dimensional construct; those treating orientation as a three-dimensional construct focused on either change occurring in orientation or the alignment between an inservice teacher's orientation and practice. There need to be more studies investigating how pre-service teachers' orientations change and how this change is reflected in both teachers' planning and other PCK components.

Methodology

Research design

The main purpose of this study was to investigate how pre-service chemistry teachers' orientation changed during a PCK-based NOS course. Moreover, how participants reflected these changes in their planning and other PCK components was examined. Because PCK and its components are tacit in nature (Loughran et al., 2004), this research is qualitative-interpretive (Marshall and Rossman, 2011). According to qualitative research tradition, case studies guided the design, collection, and analysis of the data. Yin (2009) stated that the case study method is valuable when “a how or why question is being asked about a contemporary set of events, over which the investigator has little or no control” (p. 13). The researchers had no control over the way in which pre-service teachers' orientation changed or the reflection of this change into objectives and other PCK components. Moreover, expanding and generalizing theories are the aims of a case study (Yin, 2009). This case study was designed to expand the theory of orientation as defined by Friedrichsen et al. (2011) and Roberts (1988, 2007).

Case can be defined as a phenomenon of some sort occurring in a bounded context (Miles and Huberman, 1994) and may be an individual, role, small group, organization, decision, policy, process, or event of some sort (Creswell, 2007). The selection of a case is not related to its representativeness but to its uniqueness and ability to illustrate an issue (McMillan and Schumacher, 2001). In this study, the pre-service chemistry teachers receiving PCK for NOS instruction formed the case; they were unique in that there was no other group at the university receiving any type of PCK for NOS instruction.

There are several types of case studies depending on the size of the bounded case and the intent of the case analysis (Creswell, 2007; Yin, 2009). Considering the size of the bounded case, the present study constituted a representative single-case study (i.e., one group of pre-service chemistry teachers receiving PCK for NOS instruction) because the pre-service chemistry teachers in this study represent the typical chemistry education majors in the country. In terms of intent, this case study is descriptive—the focus was to describe the way that pre-service chemistry teachers change their orientations and translate this change into both their planning and other PCK components.

Participants

The participants included 30 pre-service chemistry teachers (8 males and 22 females). They were enrolled in an elective course in which NOS was taught. All the participants were in their senior year of a five-year teacher education program and in the position of graduating at the end of the semester. After graduation they would be qualified to start their teaching profession as chemistry teachers for grades 9–12. During their five-year program, chemistry education majors take chemistry (e.g., general chemistry, analytical chemistry, organic chemistry, industrial chemistry), general pedagogical courses (e.g., Introduction to Education, Instructional Planning and Evaluation), and subject-specific pedagogical courses (e.g., Methods of Science Teaching, Laboratory Experiments in Science Education). In addition to these required courses, pre-service chemistry teachers take elective courses on chemistry and chemistry education. Each had similar background in terms of coursework. Also, they were similar in the sense that they had not received explicit NOS instruction in their previous courses. That is, the content of this course was novel for the participants.

Context: research in chemistry education course

A two-semester elective course, “Research in Chemistry Education” formed the context of this study. The course is an elective on chemistry teaching offered to senior pre-service chemistry teachers. The content of this course was determined based on recent reform movements in science education, especially chemistry education. The name of the course includes the word “research” since contemporary research studies and topics determined the content of the course.

Bearing in mind that pre-service chemistry teachers have already taken and are taking chemistry-specific pedagogical courses, the focus of the course was learning about NOS and how to teach NOS during their chemistry teaching.

The course also formed the context for the second year of a three-year project aiming to help both pre- and in-service teachers develop their understanding of NOS and their ability to teach NOS (for more information see Köseoğlu et al., 2010). Both of the authors were also researchers in this project. The institution where the authors teach was not the institution where the project was conducted. There were other researchers on the project also from other institutions. The researchers gained access to the research site with the permission of the Institutional Review Board and department chair.

The course included two instructional sections: the first was devoted to learning about NOS and the second was devoted to PCK for NOS instruction.

Nature of science instruction. Because understanding NOS is a prerequisite to teaching it, participants first learned about NOS (see Table 3). Numerous studies related to effective NOS teaching practices have favored the explicit-reflective approach over an implicit one (Abd-El-Khalick and Lederman, 2000a; Dickinson et al., 2000; Matkins et al., 2002). We utilized both content-generic and content-embedded activities to address NOS, in line with the literature. Content-generic activities included The New Society (Cavallo, 2008) and The Tube (Lederman and Abd-El-Khalick, 1998), among others. We revised several content-embedded activities to address NOS, including Competing Theories: Lamarck and Darwin (National Academy of Sciences, 1998), Sink or float: the case of candy (Lawson, 2002), and others. Additional activities were designed by the first author and the research group to address agreed-upon common aspects of NOS (Lederman et al., 2002) and common myths about NOS (McComas, 1998).

Table 3 How did each explicit-reflective NOS activity address various NOS aspects highlighted in this study?

Explicit-reflective NOS activities	NOS aspects
	Scientific knowledge is tentative	Science is based on observations and experiments	Scientific knowledge is based on inferences as well as observations	Scientific theories and laws have different roles in science	Scientific knowledge is theory-laden and includes subjectivity	Social and cultural factors affect science	Creativity and imagination play a major role in science	Science and technology are not the same thing	There is no universal step-by-step scientific method	Serendipity plays a role in science
a Modified from the activities available in literature. b Developed by researchers studying in research project.
(1) First step in NOS teaching: new society activity^a	✓	✓	✓	✓	✓	✓	✓		✓	✓
(2) Mysterious stones – lithology^b	✓	✓			✓		✓
(3) Phases of the moon – lunar and solar eclipses^b		✓			✓
(4) Competing theories – Lamarck and Darwin^a		✓	✓	✓	✓				✓
(5) Object coming from space – the role and importance of models in science^a	✓	✓	✓				✓
(6) A case from HoS: phlogiston and foundation of modern chemistry^b	✓	✓	✓		✓	✓				✓
(7) Discovery of DNA^b	✓	✓			✓	✓
(8) Thought experiments^b		✓					✓		✓
(9) Superconductivity^b	✓	✓		✓
(10) Science and technology: in the pursuit of Seharap-designs are competing^b							✓	✓

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PCK for NOS instruction. We used the activities summarized in Table 4 to stimulate the development of pre-service chemistry teachers' PCK for NOS. The first author planned the activities and a faculty member who is an expert in teaching and learning about NOS reviewed them. Magnusson et al.'s (1999) PCK model was utilized during the planning of activities to address prospective teachers' PCK components, except for the knowledge of the curriculum. Within Magnusson et al.'s (1999) model, “knowledge of curriculum” refers to teachers' knowledge on mandated goals and objectives, and specific curricular programs and materials related to the topic they teach. From an NOS perspective, this involves knowledge and use of specific curriculum materials related to NOS, as well as the various NOS objectives students are expected to achieve in particular grade levels. In Turkey there is a national curriculum and the same textbooks are used in all public schools. At the time our study was conducted, there was not an explicit purposeful emphasis on NOS within these textbooks. Additionally, there were no supplementary curricular materials available in teachers' native language (the language in which they teach) and no specific NOS objectives in the secondary chemistry curriculum standards. These conditions led us to omit teachers' knowledge of curriculum from our study. The teaching module spanned four weeks, which correspond to 12 in-class hours. To elicit their ideas about the targeted component of PCK for NOS, each class session began with students answering a series of open-ended questions. Next, students engaged in argumentative discussions about a case, targeting a particular PCK component within small groups, and presented their ideas to the class. For example, in one session, students watched a video then considered what types of knowledge the individual shown in the video would need to make an informed decision about swine flu. The instructor facilitated the discussions and wrapped up the instruction with a presentation related to the session's focus. Participants ended the session by writing a reflection on their learning. Although we use the phrase “PCK for NOS instruction,” this does not mean that we explicitly introduced the PCK construct to participants. Rather, we asked framing questions aligned with this construct during each session (e.g., “Why are you teaching science?” for science teaching orientations and “What kind of instructional strategies do you use for teaching NOS?” for knowledge of instructional strategies).

Table 4 Activities designed to enhance different components of PCK for NOS

Target PCK component	Example learning activities
Orientations
Debating on what knowledge is needed to decide on socio-scientific issues facilitated students' reflection and revision of their purposes and goals for teaching science	(1) Watch a video of a mother who has to decide whether or not to get her baby vaccinated for swine flu (socio-scientific decision making). (2) Debate conflicting ideas by two different teachers (one claims that it is enough to know biology and science concepts and the other advocates that further knowledge is needed to decide on socio-scientific issues).
Learner
Arguing about various NOS conceptions enabled students to realize areas of science that students find difficult including misconceptions of NOS	(1) Explain to participants the letters (including concept cartoons on myths of NOS) received from teachers who encountered problems in their class and needed participants' help. (2) Argue about various NOS conceptions: which one is accepted, which one is a misconception. What is the source of misconceptions? And how can a teacher challenge a student to confront his/her misconceptions?
Instructional strategies
Analyzing two lesson plans and arguing on two science educators' views on lesson plans helped students to understand implicit and explicit-reflective approaches to NOS teaching and thus enhanced their knowledge of strategies and representations for teaching NOS.	(1) Case study scenario: assist a chemistry teacher needing help in designing a chemistry lesson in a way to teach both chemistry and NOS concepts. (2) Distribute two lesson plans prepared on the same chemistry concepts: one where teaching NOS is implicit and the other where teaching NOS is explicit-reflective. (3) Analyze lesson plans in terms of alignment between their intended objectives, the teaching method and the appropriateness of teaching method achieving (or satisfying) the objectives. (4) Argue about two science educators' views on lesson planning: one supports an implicit approach and the other one supports an explicit-reflective approach.
Assessment
Assisting a teacher with aligning his/her assessment task with the lesson objectives including chemistry and NOS helped students to consider NOS as a dimension of science learning and the methods by which NOS can be assessed	(1) Give both chemistry and NOS objectives from lesson plans analyzed in the previous class. (2) Case study scenario: assist a chemistry teacher with aligning his/her assessment task with the lesson objectives. (3) Ask pre-service teachers to give specific examples of an assessment task.

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Data collection sources

Qualitative data sources were used to gain in-depth information about the phenomenon being investigated (see Fig. 2). Responses given to open-ended instruments, interviews, observations, and documents such as lesson plans and reflection papers were used as sources of data. Views on Nature of Science Questionnaire Form C (VNOS C, Lederman et al., 2002) in conjunction with follow-up interviews before and after the first course were used for assessing pre-service chemistry teachers' views on NOS. To investigate the change in pre-service teachers' orientations during the course, and how this change is reflected in their planning and other PCK components, we utilized lesson plans, interviews, reflection papers, responses given to open-ended instruments, and observational records, including videos.

Fig. 2 How data collection occurred within the various course activities.

Open-ended questions. Two types of open-ended questions were used during data collection. To understand whether learning NOS influenced participants' views on chemistry teaching and to compare their views on chemistry teaching before and after PCK for NOS instruction, several open-ended questions were utilized: What is the goal of science and especially chemistry education? What kind of instruction do you design to achieve the goals you mentioned in previous questions? What are the difficulties that you may encounter when you are teaching what you want to teach? Up until now, what have you learned from this class about chemistry teaching? Other open-ended questions were unique and designed to evaluate each PCK component (Table 5).

Table 5 Pre-questions asked before each PCK for NOS instruction class

Class	Questions
STO	As a teacher candidate, in your view, what is the goal of science education and specifically chemistry education? As a teacher, in your view, what kinds of knowledge, skills, etc. should a student have as a result of science and especially chemistry teaching?
KoL	What might your students already know about NOS? Why do you think that they might know that? Where do you think they might have learned that?
KoIS	What kind of instructional strategies do you use for teaching NOS and chemistry concepts in the same course hour?
KoA	How would you help a teacher who has difficulty in assessing his objectives for both chemistry and NOS? What suggestions would you give for assessments?

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Reflection papers. Pre-service teachers were asked to write a reflection paper following each PCK for NOS session. These reflection papers were used to clarify each session's effect on pre-service chemistry teachers' knowledge about related PCK components. The questions in reflection papers included the following: What is the message that this lesson wants to give? What did you learn about chemistry/science education? How did this lesson change your perspective on chemistry/science education? How do the things you learned in this lesson affect your chemistry/science teaching?

Interviews, lesson plans, and observations. To gain an in-depth understanding of the development of pre-service chemistry teachers' orientation, and the reflection of this development to their planning and other PCK components, interviews, lesson plans, and observations were used. Participants were asked to prepare two lesson plans—one before PCK for NOS instruction and one after. The first lesson plan gave insight into whether participants reflected their NOS-related orientation, if it existed, in their chemistry teaching after having learned about NOS. The second lesson plan was used to investigate how PCK for NOS instruction stimulated a change in pre-service chemistry teachers' orientation, and the translation of their orientation into their lesson plans and PCK components. All class sessions were videotaped to supplement the data collection since each individual data source has limitations in terms of providing a full picture of teachers' orientation. Below are several example interview questions:

• Was there any change in your views about what you expect students to learn about chemistry before NOS instruction, after NOS instruction, and after PCK for NOS instruction? If yes, how?

• Do you think that your students should learn NOS? Was there any change in your views about this before NOS instruction, after NOS instruction, and after PCK for NOS instruction? If yes, how?

Data analysis

Three main analyses were conducted to determine how the pre-service chemistry teachers' NOS understanding and their orientation changed throughout PCK for NOS instruction.

Analysis of NOS views. Data obtained from VNOS-C and follow-up interviews were analysed deductively to identify how participants' NOS views changed after NOS instruction. To determine participants' NOS views, we used the existing categorization proposed by Khishfe and Abd-El-Khalick (2002). Khishfe and Abd-El-Khalick (2002) advocated that there is a continual change in students' understanding about NOS. Bearing this in mind, pre-service chemistry teachers' NOS understandings were categorized as naive, transitional, or informed. Each NOS aspect was evidenced in more than one data source (interview and VNOS-C) and in more than one item in VNOS-C. A participant's view on a particular aspect was categorized as informed if s/he provided evidence of a meaningful understanding related to that aspect in all contexts. If a participant had not exhibited any meaningful understanding with respect to a particular aspect in all contexts, his/her view of the related aspect was categorized as naïve. If a participant had demonstrated meaningful understanding of a particular aspect in some contexts but not others, his/her view in that aspect was categorized as transitional.

Translation of change in science teaching orientation to instructional plan and other PCK components. This analysis (Patton, 2002) focused on lesson plans, reflection papers, responses to open-ended questions, and interviews. In the first round of analysis, we aimed to understand how pre-service teachers translated the change in their orientation to their instructional planning. We examined to what degree their lesson plans included objectives aligned with their orientation. When deciding whether an objective is a reflection of a particular orientation, we formed a coding scheme describing instances for each orientation and its associated objectives (Table 6).

Table 6 Coding scheme describing instances of reflection on orientations (Roberts 1988, 2007) in lesson plan objectives

Curriculum emphasis	Definition	Definition of objective and sample objective statements reflecting curriculum emphasis
Everyday coping	Students use science to comprehend everyday objects and events.	Objectives related to explaining daily life events (students explain why some reactions occur fast (e.g., explosion) and slow (e.g., rusting) in daily life).
Structure of science	Students understand how science functions as an intellectual enterprise.	Objectives related to NOS (students understand that modern atomic theory may change with new evidence and re-interpretation of existing evidence).
Science, technology, and decisions	Students understand the interrelationship between science, technology, and society and hence make informed decisions about socio-scientific issues.	Objectives related to informed-decision making (students produce reasonable arguments about building power plants).
Scientific skill development	Students acquire conceptual and manipulative scientific process skills.	Objectives related to scientific process skills (students observe, design experiments, and interpret the data).
Correct explanation	Students learn the ends of scientific inquiry, which are concepts, theories, laws, models etc. in a scientific discipline.	Objectives related to students' learning of scientific knowledge (students explain the acid–base theories).
Self as explainer	Students understand the efforts to explain phenomena by appreciating the conceptual underpinnings that influenced scientists in the process of developing explanations.	Objectives related to students' intellectual freedom (students understand that science helps them to be free knowledge seekers).
Solid foundation	Students use science to get ready for the topics they are going to learn next year.	Objectives related to science content that is necessary for next year (students understand intermolecular forces to learn intramolecular forces).

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In the second round, we conducted an in-depth analysis of explicit PCK (Park and Oliver, 2008; Park and Chen, 2012) to reveal how science teaching orientation interacted with other PCK components. This method relies primarily on the construction of a PCK profile for each participants as defined by Magnusson et al.'s (1999) model. The PCK profile consisted of several components (see Appendix), including (a) the chemistry topic on which the lesson plan was prepared, (b) objectives, including science process skills and NOS aims to be achieved, (c) synopsis of the lesson plan prepared after PCK for NOS instruction, (d) evidence of the components of PCK for NOS and connections among them, (e) a description of where the PCK for NOS components were evident throughout the data collection, and (f) post-intervention PCK for NOS map representations, in which components and connections or consistencies are present. The final PCK for NOS map included only four components of Magnusson et al.'s (1999) model, namely, science teaching orientation, knowledge of the learner, knowledge of instructional strategy, and knowledge of assessment, since knowledge of curriculum was not a focus in PCK for NOS instruction. Different types of lines were used to show connections and consistencies among orientation and other PCK components, which were evident in different data sources:

• Bold lines for the connections and consistencies that exist in lesson plans

• Solid lines for the connections and consistencies that exist in reflection papers

• Dashed lines for the connections and consistencies that do not exist in any of the data sources

With recognition of the way in which orientation shapes other PCK components (Magnusson et al., 1999), any integration between those components was coded as consistency. Since the focus of this study was to examine how the change in science teaching orientation is translated into other PCK components, we were interested in consistencies between orientation and other PCK components. Results regarding connections between PCK components were presented elsewhere (Demirdöğen et al., 2015). In order to decide whether consistency was evident in any of the data sources, a coding scheme was formed.

This coding scheme described the instances of PCK components and integration of components in pre-service chemistry teachers' PCK. During the formation of the coding scheme, we relied on the data and literature using in-depth analysis of explicit PCK (Park and Oliver, 2008; Park and Chen, 2012). Based on the data and the literature, we defined every possible instance that could be counted as an evidence for consistencies between orientation and other PCK components. Two researchers who are experts on PCK built the coding scheme by discussing and negotiating any incongruities (see Table 7).

Table 7 Coding scheme describing instances of PCK components and integration within them

PCK components	Instance	Consistency	Direction
STO-KoL	• If pre-service teacher is aware that students have misconceptions about NOS • If pre-service teacher is teaching one of the myths about NOS (e.g., hierarchical relationship between theory and law)	Consistent	STO influenced KoL
STO-KoIS	• If pre-service teacher uses implicit or explicit approach to teach NOS	Consistent	STO influenced KoIS
STO-KoA	• If pre-service teacher assesses NOS	Consistent	STO influenced KoA

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Credibility issues of the study

In this study, triangulation and prolonged engagement were used to ensure credibility. We used multiple data sources to triangulate our findings as well as analyst/investigator triangulation using multiple observers, interviewers, and analysts. Throughout all course instruction and data collection processes, two researchers who are familiar with NOS and PCK were present. During the analysis stage, these two researchers independently coded the data for both NOS and orientation after forming a rubric for each part. The rubric for NOS came directly from NOS literature (Khishfe and Abd-El-Khalick, 2002). The coding schemes used in creating PCK profiles and evaluating the reflection of orientation in lesson planning were formed by the authors, who are experts on PCK, by discussing and negotiating any incongruities. After formation of the rubric and coding scheme, two independent researchers coded the data for NOS and orientation. The incongruities between researchers were resolved by negotiation and discussion. Inter-rater reliabilities were calculated at 95% for NOS and 90% for orientation.

Prolonged engagement was achieved by being present in the research site for an extended period of time. Two of the researchers spent a full year, two semesters of class time, within this research setting and with these participants. Most of the time, two authors were among the leading instructors of the class and had a chance to observe and talk with participants both in and outside of the classroom setting.

Ethical issues of the study

We conducted all study activities in alignment with the Institutional Review Board (IRB). All participants voluntarily participated in the study and submitted written consent form. They were also aware of the role of participant observers, who also had teaching roles during class sessions. The Department Chair served as an external gatekeeper; that role was to act as a point of contact for participants to voice any concerns. The names of the subjects were removed from all data collection forms by giving pseudonyms to participants. Hence, issues regarding ethics in research (i.e., protection of the participants from harm and confidentiality) were negated (Fraenkel and Wallen, 2006).

Findings

In line with the focus of this study, we will present our findings under four sections: (1) the change in NOS understandings, (2) the change in science teaching orientation, (3) translation of change in orientation into instructional planning, and (4) translation of change in orientation into other PCK components.

The change in NOS understanding

Pre-service chemistry teachers had various misconceptions about NOS (e.g., “hypotheses become theories that turn into laws,” or “scientists are particularly objective”) before NOS instruction. The combined percentage of naïve (33%) and transitional (28%) views was 61%, whereas the percentage of informed views was 26% (13% of the views were missing). The majority of the participants (80%) had naïve views about the theory-law aspect of NOS, though no participant had naïve views about the creative and imaginative aspect. However, 43% of the participants had transitional views regarding the creative and imaginative aspect of NOS. Participants' NOS views changed in the desired way after the NOS instruction. The average percentage of transitional (21%) and naïve (5%) views decreased considerably, whereas the percentage of informed views increased to 73%. Pre-service chemistry teachers still had difficulty understanding empirical-based (7%) and sociocultural embedded NOS (7%), as well as the differences between theory and law (13%), and observation and inference (10%), in spite of the increase in informed NOS views (see Fig. 3).

Fig. 3 The comparison of VNOS-C results obtained from its administration before and after NOS instruction.

The change in science teaching orientation

Analysis of data revealed that participants had almost the same orientations before and after NOS instruction. This is an indication that adequate NOS understanding is not enough to stimulate a change in pre-service chemistry teachers' science teaching orientations. During an interview, Grey explained this, saying “In the first part where we learned about nature of science, I did not think that nature of science is something that I should teach to my students.” There were only three pre-service chemistry teachers who added structure of science to their pre-existing orientations. Therefore, we have only presented the change in participants' science teaching orientations before and after PCK for NOS instruction. Regarding the nature of pre-service chemistry teachers' orientations, data indicated that participants did not have a single orientation. They were orientated to teach chemistry for several purposes at the same time throughout the course. For instance, Debbie explained her purposes of chemistry teaching in a reflection paper that she wrote after PCK for NOS instruction: “The purpose of chemistry teaching is to reach scientific literacy by helping students to understand and gain science process skills, nature of science as well as chemistry concepts.” Table 8 indicates some participants' pluralities in science teaching orientation and how their orientations changed after PCK for NOS instruction.

Table 8 Examples of the change in orientations that several pre-service chemistry teachers experienced

Participant	STO before PCK for NOS	STO after PCK for NOS
Howard	Correct explanation Everyday coping	Science, technology and decisions A structure of science Everyday coping
Fletcher	Scientific skill development Correct explanation Self as explainer	Scientific skill development Correct explanation Self as explainer
Irving	Everyday coping Self as explainer	Everyday coping Scientific skill development A structure of science
Grey	Everyday coping Scientific skill development Self as explainer	Everyday coping A structure of science Self as explainer
Sandra	Everyday coping Scientific skill development	Everyday coping Scientific skill development A structure of science Science, technology, and decisions
Florrie	Everyday coping Correct explanation Scientific skill development	Everyday coping Correct explanation A structure of science Self as explainer

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Data showed that all pre-service teachers aspired to increase their students' ability to explain daily life phenomena using scientific knowledge before PCK for NOS instruction (Fig. 4). The vast majority of participants (90%) were open to moulding students to be intellectually open-minded through chemistry instruction. Increasing students' scientific skill development was the third most frequent orientation among pre-service teachers (57%). Orientations toward correct explanations (23%) and science, technology, and decisions (20%) were held by one fifth of the participants. The degree to which pre-service chemistry teachers' orientations changed varied in different categories of orientation. Everyday coping, correct explanation, solid foundation, and scientific skill development were the orientations where the least amount of change was observed. The change in the “self as explainer” orientation was mediocre. The most noticeable change occurred in two orientations: structure of science and science, technology, and decisions. The order of the frequency of the orientations changed after PCK for NOS instruction in most of the categories. Everyday coping still was the most frequent orientation (93%). However, a majority of the participants were oriented to teach the structure of science after the instruction (90%). Two thirds of the pre-service chemistry teachers also started to include science, technology, and decisions among their orientations (73%)—a change from their previous preferences. Although there was a 25% decrease the in frequency of self as explainer orientation, about 60% of the participants still aimed to teach chemistry for scientific skill development and fell into the self as explainer orientation. Teaching chemistry for correct explanations was still the least common orientation, despite the increase in frequency.

Fig. 4 The change in participants' science teaching orientations before and after PCK for NOS instruction.

Translation of change in orientation into instructional planning

All of the pre-service chemistry teachers had NOS related orientations (i.e., structure of science or science, technology, and decisions) after PCK for NOS instruction (see Fig. 4). Aligned with this finding, data revealed that pre-service chemistry teachers focused on at least one aspect of NOS in their lesson plan (Fig. 5). In other words, participants were able to translate the change in their orientation into their instructional planning (evidenced by the objectives in their lesson plan prepared after PCK for NOS instruction). This is also an indication that participants started to see NOS as a cognitive outcome of the learning and teaching process.

Fig. 5 Number of objectives related to NOS and scientific process skills in lesson plans prepared after PCK for NOS.

The pre-service chemistry teachers' lesson plans were different from each other in terms of both the number of NOS-related objectives and the particular NOS aspect addressed in the objectives. Nearly half of the participants (43%) designed their lesson plans to teach one NOS aspect. The percentages of participants focusing on four and five aspects of NOS in their instructional plans were the same, 17%. There were four pre-service teachers who included four NOS aspects in their planning (13%) whereas three participants (10%) chose to emphasize three aspects of NOS. The most frequent NOS aspects addressed in lesson plans (Fig. 5) were the role of creativity and imagination (10), the theory-laden nature of science (9), and the myth of a universal step-by-step scientific method (8). Seven participants included the tentative nature of scientific knowledge and seven included the empirical basis of science in their lesson plans. There were six pre-service chemistry teachers who designed their lesson to teach the cumulative nature of scientific knowledge and six who focused on observation, inference, and the differences between them. Although the majority of the participants had naïve views about theories and laws before NOS instruction (80%), only four of them designed their lesson to teach the nature of theories and laws. The number of pre-service teachers who addressed the difference between science and technology, the nature of classification, and scientific models in their plans was the same (2), which was low. The sociocultural-embedded nature of science and differentiating science from non-science were the least frequent NOS aspects addressed in participants' planning (1).

Despite the fact that pre-service chemistry teachers were able to reflect NOS-compatible orientations in their planning, the situation was a different translation of scientific process skills related orientation into their planning. Although 18 participants had a scientific skill development orientation after PCK for NOS instruction, only 11 of them included objectives related to scientific process skills in their lesson plans.

Translation of change in orientation into other PCK components

The consistencies evident in all 30 pre-service chemistry teachers' lesson plans (represented by bold lines) or reflection papers (represented by solid lines) were compiled into a comprehensive PCK for NOS map (Fig. 6) to provide a summary of the most and least frequent consistencies and to identify the outstanding features of the integration of the PCK components within the group as a whole. Bold lines indicate the consistencies between PCK components that participants were able to reflect to their lesson plans; we categorized these types of consistencies as “application level.” On the other hand, consistencies represented by solid lines were evident in reflection papers but not translated to lesson plans. We categorized these types of consistencies as “knowledge level.” Fig. 6 shows the frequency of integrations among all PCK components evident in both lesson plans and reflection papers. However, this study is interested in translation of the change in orientation to other PCK components. Findings regarding integration among knowledge of learner, instructional strategy, and assessment were presented elsewhere (Demirdöğen et al., 2015).

Fig. 6 Group PCK for NOS map showing the frequency of integrations among PCK components.

The analysis of the data revealed some features of the integration between orientation and other PCK components. First, when pre-service chemistry teachers developed knowledge of the learner, assessment, and instructional strategy either at the knowledge or application level, they succeeded in aligning these components with their NOS-related orientation. That is, they were aware that students may have misconceptions and difficulties regarding NOS (e.g., confusing observation and inference or believing experiments are the principal route to scientific knowledge), and they used instructional strategies, such as various types of explicit-reflective approaches, to communicate information and to overcome misconceptions. Finally, they assessed students' understanding of NOS using several assessment techniques (e.g., concept maps, concept cartoons, true–false questions, and question–answer method).

Another salient feature of the participants' post-intervention PCK for NOS map was that orientation and knowledge of instructional strategy were central to the integration. That is, they were the most frequently connected aspects compared to any two others. In addition, the consistency between orientation and knowledge of instructional strategy was the only one that all participants could translate into lesson plans. When we looked at how pre-service chemistry teachers successfully aligned their instructional strategy with their orientation of teaching NOS (STO), all but three decided to use various types of explicit-reflective approaches in their planning. Inquiry was the most preferred instructional teaching strategy (16) and the order of preferences for other instructional strategies was as follows: inquiry together with history of science (5), history of science (3), case-based (2), and activity (1). Only three of the participants used an implicit approach for teaching NOS and again inquiry was preferred by two of them; history of science was used by one.

Third, when we compared the number of participants who aligned their knowledge of the learner, assessment, and instructional strategy with their orientation in knowledge versus application (e.g., articulated in reflection papers but not lessons), we saw that translating the knowledge of the learner into lesson plans was the greatest area of difficulty (see Fig. 6). Of the participants, 16 provided evidence about the learner component of their PCK through focusing on helping students to eliminate at least one of their misconceptions or difficulties related to NOS. On the other hand, nine out of ten pre-service teachers with knowledge of the learner evident in their reflection papers had only general ideas about their learners, such as “students may have misconceptions or prejudices about science.” For instance, after a lesson in which participants learned about difficulties and misconceptions regarding NOS, Katy stated, “Since I have had similar misconceptions before this lesson, I know that it is hard to eliminate students' misconceptions about the nature of science. Therefore, I will be careful when teaching ideas about the nature of science and try to eliminate misconceptions about NOS.” However, she did nothing to elicit and eliminate these misconceptions in her lesson plan.

Fourth, in terms of assessment of knowledge, participants were more successful in translating their knowledge of assessment to their lesson plans than applying their knowledge of the learner. Out of 30 participants, 22 assessed NOS in their lesson plans using various techniques. Distribution of student teachers among the assessment techniques was as follows: concept map (6); informal assessment (4); giving examples (2); poster (2); video-case (2); project work on the chemistry topic and emphasized NOS aspects (1); written case (1); cartoon (1); concept cartoon (1); true–false test (1); research on focused aspects (1); and diagnostic tree (1). On the other hand, of the six participants who showed consistency between assessment knowledge and orientation at the knowledge level and were aware that they should assess students' understanding of NOS and of the various methods they can utilize to assess (e.g., concept maps, concept cartoons, true–false items, and case), four did not consider assessing NOS in their lesson plans. The two remaining participants demonstrated an even lower developed awareness than he other four, just explaining in their reflection papers that they should consider assessing NOS.

Discussion

The purpose of this case study was to shed light on how science teaching orientation changes during a PCK-based NOS course. Moreover, we were interested in pre-service teachers' translations of those changes into their planning and other PCK components. We utilized Magnusson et al.'s (1999) PCK model and Friedrichsen et al.'s (2011) orientation model. Interviews, responses to open-ended instruments, reflection papers, and lesson plans yielded four sections under which we presented our findings: (1) change in NOS understanding, (2) change in science teaching orientation, (3) translation of change in orientation into instructional planning, and (4) translation of change in orientation into other PCK components. We will discuss our findings in the following section.

Regarding the change in NOS understanding, a vast majority of the pre-service chemistry teachers had naïve and transitional views about various NOS aspects before NOS instruction, as has been indicated elsewhere (Abd-El-Khalick and BouJaoude, 1997; Doğan et al., 2011; Mesci and Schwartz, 2016). Most of the pre-service teachers had naive views on the theory and law aspect. Sociocultural-embedded and theory-laden NOS aspects were almost as poorly understood. These findings were similar to those of others (Chen, 2001; Liang et al., 2008), revealing that both pre- and in-service teachers experience difficulty in understanding theory and law, sociocultural-embedded aspects of science, and theory-laden NOS aspects. The creative and imaginative aspect was the one about which participants had only transitional and informed views, which is in line with the literature (Akerson et al., 2000). Analysis of pre-service chemistry teachers' views after NOS instruction indicated that most of the participants tackled their naïve and transitional views on most of the NOS aspects, however a few of them still had naïve views about several NOS aspects (e.g., empirical-based, social-cultural embedded, observation and inference, and theory and law). These findings are consistent with the results of studies investigating the effects of various teaching approaches on NOS understanding (Abd-El-Khalick et al., 1998; Abd-El-Khalick and Akerson, 2004). Those findings provide evidence for the fact that pre-service chemistry teachers' naïve views about those aspects are resistant to change even after explicit-reflective NOS instruction. Also, this is compatible with research pointing out that misconceptions are resistant to change (Posner et al., 1982). Pre-service chemistry teachers have built their NOS understanding as a result of their primary, secondary, and higher education. Throughout one's education, science textbooks, teachers, classroom instruction, and laboratory experiences have been perceived to influence the formation of students' NOS understanding (McComas et al., 1998). For instance, until recently, the hierarchical relationship between theory and law has been presented in science textbooks while explaining the scientific method (Abd-El-Khalick et al., 2008). Some instructional, motivational, and sociocultural factors might also explain why pre-service chemistry teachers still have difficulty in understanding theory and law, and observation vs. inference (Mesci and Schwartz, 2016). Even though those aspects were addressed several times through the use of various activities during the course (see Table 3), pre-service chemistry teachers might need more hands-on activities, class discussions, examples, and readings. Personal (e.g., utility value and self-efficacy) and social (e.g., peer support and team work) motivational factors might also affect the degree to which pre-service teachers successfully understand the NOS aspects. Lastly, background experiences (i.e., being taught by inquiry) and worldview (e.g., reluctance to accept ambiguity) might create an obstacle for some pre-service teachers attempting to change their naïve ideas about observation vs. inference and theory and law. Although pre-service chemistry teachers had naïve and transitional views on numerous NOS aspects, there was a substantial increase in the percentage of participants with informed views on the majority of the NOS aspects as a result of explicit-reflective NOS instruction. This is consistent with the findings of research investigating the positive effect of this kind of NOS instruction over implicit instruction (McDonald, 2010; Burgin and Sadler, 2016). More specifically, various settings, namely, argumentation, inquiry, and history of science, served as contexts throughout the explicit-reflective NOS instruction in this study. The effectiveness of those environments, where learners are provided authentic science experiences, on NOS understanding was also supported by others in terms of the history of science (Abd-El-Khalick and Lederman, 2000b), argumentation (McDonald, 2010), and inquiry (Yacoubian and BouJaoude, 2010).

Investigation of how pre-service chemistry teachers' orientations changed during the course revealed that they had multiple orientations throughout the course and there was an increase in NOS-related orientations (e.g., structure of science and science, technology and decisions) at the end. Participants' plural nature of orientations is consistent with the literature, which states that teachers have multiple goals and purposes (Friedrichsen and Dana, 2005; Aydın and Boz, 2013). The value of helping pre-service teachers to develop more reform-based orientations through multiple teacher education courses and professional development programs has also been supported by other studies (Faikhamta, 2013; Campbell et al., 2014). Unlike those studies, this study also investigated how pre-service teachers, whose orientations became more reform-based at the end, translated their orientations into their instructional planning as indicated by their objectives. Participants were able to translate their NOS-related understanding into the lesson plans that they prepared after PCK for NOS instruction. Their plans included at least one successfully communicated NOS aspect. This is expectable considering pre-service teachers plan 40 minute lessons. Also, some topics in chemistry are suitable for teaching one aspect of NOS (i.e., gas laws and kinetic molecular theory are suitable for teaching theories and laws) whereas others provide context for teaching two or more NOS aspects (i.e., definitions of acids and bases are suitable for teaching tentativeness and nature of theories). Pre-service teachers including at least one NOS aspect in their planning is evidence indicating that PCK for NOS instruction helped pre-service teachers to see NOS as an important cognitive learning outcome on the same level as scientific content-related ones (Abd-El-Khalick et al., 1998; Schwartz and Lederman, 2002; Lederman, 2007). This finding may be attributed to the nature of PCK for NOS instruction. During the session on science teaching orientation, we satisfied the conditions for conceptual change in pre-service teachers' orientations. That is, first, we elicited their orientations and created dissatisfaction by indicating why their orientations may not fully help them to instruct and produce scientifically literate individuals, as suggested by others (Aydın and Boz, 2013). Second we developed participants' understanding of scientific literacy and the role of NOS in achieving scientific literacy for intelligibility. Third, we achieved the plausibility of a new orientation by indicating how NOS-related and reform-based orientations could be integrated into teachers' existing science teaching orientations (e.g., everyday coping). To ensure plausibility, it was also emphasized that different topics in chemistry are suitable for teaching different numbers of NOS aspects. Some topics are suitable for teaching one aspect of NOS meaningfully while others provide opportunities to teach more than one NOS aspect. Also, we discussed the importance of designing a lesson that helps students meaningfully learn at least one NOS aspect instead of teaching many NOS aspects during a lesson. Finally, conveying to pre-service teachers how NOS-related orientations are applicable to all grades from kindergarten to university ensured a solid understanding and appreciation of the concept. Pintrich (1990) and Kagan (1992) are the pioneers who proposed the application of conceptual change theory in changing teachers' beliefs. However, there are several differences between conceptual change in understanding of a concept and conceptual change in belief. First, meaningful learning is the aim of conceptual change in understanding (Novak, 2002), and a belief revision is more permanent when a conceptual change occurs (Ohlsson, 2009). Pre-service teachers revised their beliefs to value NOS after PCK for NOS instruction. Second, the learner perspective dominates one's thinking during the conceptual change of an understanding, while the teacher perspective directs thinking when there is a conceptual change in a teachers belief (Bryan, 2003). By promoting the plausibility of new orientations and fostering appreciation for their school-wide implementation, we enabled participants to think from a teacher perspective rather than that of a learner who understands what scientific literacy is and the role of NOS in achieving scientific literacy. Third, knowledge changes through “well-established canons of argument,” while beliefs do not (Nespor, 1987; Joram and Gabriele, 1998). There are several motivational and epistemological factors that affect belief change (Patrick and Pintrich, 2001). Teacher educators invite pre-service teachers to entertain alternate realities and consider how new ideas are compatible with and enhance their existing beliefs (Joram and Gabriele, 1998) (i.e., plausibility of conceptual change achieved during PCK for NOS instruction).

Although pre-service chemistry teachers were able to reflect their NOS-compatible orientations in their planning for the most part, there was less translation of the orientation related to scientific process skills. Pre-service teachers generally did not successfully integrate scientific process skill-related objectives in their planning (11 out of 18). This may be explained by the fact that some goals and purposes may be central while others are peripheral (Friedrichsen and Dana, 2005). Pre-service teachers' content- and NOS-related orientations might dominate their thinking throughout the objective writing process whereas other goals (e.g., scientific skill development) might be less influential.

Translation of the change in pre-service teachers' orientations into other PCK components was different for each PCK component both at the application and the knowledge level. All pre-service teachers aligned their NOS-related orientations with their instructional strategy at the application level in their planning, which is compatible with the finding that teachers' development of instructional strategies is higher than development of other PCK components (Abd-El-Khalick et al., 1998; Bell et al., 2000; Hanuscin et al., 2011). After the instructional strategy component of PCK, knowledge of assessment is the component change that the most pre-service chemistry teachers translated into their NOS-related orientations. In contrast to prior studies (Bell et al., 2000; Hanuscin et al., 2011) indicating teachers' inability to assess NOS, our PCK for NOS instruction helped student teachers to align their beliefs with their practices (Abd-El-Khalick et al., 1998) and to increase their knowledge of assessment in terms of both what and how to assess (Hanuscin et al., 2011). Moreover, PCK for NOS instruction prevented pre-service teachers from getting lost in the complexity of assessment. Knowledge of assessment is more complex than its original definition (Lannin et al., 2008). What and how teachers assess is determined by teachers' assessment philosophies (i.e., beliefs and values about assessment) and purposes. Pre-service teachers aligned their assessment philosophies and purposes with what and how they assess. The knowledge of learner component of PCK was the most difficult component to translate at the application level. Several studies provided consistent findings about teachers' inability to adequately consider students' ideas in practice (Tabachnick and Zeichner, 1999; De Jong and Van Driel, 2001; Park and Chen, 2012). Participants in this study did not have the chance to implement their lesson plans in real classrooms. They were not able to align their NOS-related orientation with the knowledge of the learner in their lesson plans, which supports the explanation that knowledge of the learner improves with teaching experience (Abell, 2007). This situation could also be explained by the fact that “…increased knowledge in a single component may not be sufficient to stimulate change in practice” (Park and Chen, 2012, p. 939).

PCK is known for its topic-specific nature (van Driel et al., 1998). However, Davis et al. (2008) advocated that “…while PCK is typically conceptualized as topic-specific, teachers also need discipline-specific knowledge about how a discipline works” (p. 6). In addition, Davis and Krajcik (2005) defined PCK for disciplinary practices, saying “teachers must know how to help students understand the authentic activities of a discipline, the ways knowledge is developed in a particular field, and the beliefs that represent a sophisticated understanding of how the field works” (p. 5). Based on Veal and MaKinster's (1999) taxonomy for PCK, discipline-specific PCK could be defined as the PCK relevant for different disciplines (e.g., science, mathematics, or history). Therefore, chemistry teachers' PCK for NOS includes their knowledge and skills for teaching NOS effectively, since chemistry is a domain in the discipline of science. Moreover, the NOS aspects addressed in this study and in pre-service chemistry teachers' lesson plans are domain-general, not specific to the domain of chemistry (Abd-El-Khalick, 2012). Accordingly, in this study, discipline-specific PCK helped us to explain pre-service teachers' NOS teaching practices across different topics in chemistry. For instance, one participant prepared a lesson on atomic theories and another participant designed a lesson on acid–base theories. However, both of them preferred to use explicit-reflective strategies to teach about the nature of theories. In other words, they both drew on PCK for teaching the nature of theories.

Finally, this study provided evidence for the applicability of Friedrichsen et al.'s (2011) multidimensional definition of orientation. Pre-service teachers who have an informed NOS understanding (i.e., beliefs about NOS dimension of orientation) and whose goals or purposes of teaching are NOS-related (i.e., beliefs about the goals or purposes of science teaching) are able to translate these beliefs into their planning, as indicated by their objectives. During this translation, their beliefs about science teaching and learning (i.e., the other dimensions of orientation) helped them align their instruction with their beliefs about both NOS and the goals of science teaching. That is, interaction occurs between orientation (defined as an interrelated set of beliefs in this study) and other components of PCK for NOS when the dimensions of the orientation relate to each other. When pre-service teachers value NOS as one of their purposes for teaching science, they put their other relevant PCK components into play to teach NOS effectively. This is compatible with the fact that belief in the importance of teaching NOS is an important factor enabling teachers to translate their beliefs about NOS into their teaching (Schwartz and Lederman, 2002). This study also revealed that reflection (Boz and Uzuntiryaki, 2006; Park and Oliver, 2008) and use of PCK (Aydın et al., 2013) might be fruitful in providing the necessary conditions for the interaction between orientation and other PCK components. Pre-service teachers reflected on their orientation and the translation of their orientation into their teaching during all sessions of the PCK for NOS instruction. Moreover, how their orientation relates to other PCK components was emphasized through the use of the PCK framework throughout this instruction.

Implications for research and teacher education

The present study was one of the first to examine both how pre-service teachers' orientations change throughout a teacher education course and the way pre-service teachers translate this change into their planning and PCK. Therefore, the findings of this study have valuable implications for teacher education and research.

Pre-service chemistry teachers have existing beliefs when they enter teacher education programs (Putnam and Borko, 1997), as this study also reveals. Pre-service chemistry teachers' orientations transformed into more reform-based ones at the end of PCK-based NOS instruction. Also, pre-service chemistry teachers were able to align their instructional planning and PCK with their orientation to a reasonable degree. Based on these findings, chemistry teacher educators should develop new methods to make beliefs explicit. Moreover, they should provide opportunities in which pre-service chemistry teachers experience a conceptual change in their orientations (Koballa et al., 2005) if they need to revise their orientations. To help pre-service chemistry teachers align their beliefs with their practice, they should be introduced to their professional knowledge base (i.e., PCK) and the role of their orientation within their knowledge base. Chemistry teacher educators should also ensure that reflection occurs in various settings, such as the Science Teaching Method course, NOS course, and practicum.

Orientation needs to be theoretically defined and empirically supported in terms of both its dimensions and sub-dimensions. Also, the role and nature of central and peripheral orientations should be investigated in detail to reveal their influence in instructional planning and practice. Although this study focused on pre-service chemistry teachers' orientations, studying pre-service teachers from other disciplines (e.g., physics) at a secondary level or teachers of science at an elementary level may contribute to understanding about the nature of orientation.

Regarding the nature of PCK for NOS, more studies are needed to investigate whether the discipline-specific nature of PCK fully captures science teachers' NOS teaching practices across different domains (e.g., chemistry and physics). Examining a physics teacher's and a chemistry teacher's NOS teaching practices for the same topic, such as the atom, might resolve this issue. This kind of study would also contribute to our understanding about the emergence of domain-specific changes regarding how NOS aspects are addressed.

Limitations of the study

There were several limitations inherent to this study. First, the findings are limited to the pre-service teachers enrolled in the course. However, generalizing the findings is not the aim of this case study. We attempted to expand the theory of science teaching orientation proposed by Friedrichsen et al. (2011) and the model of PCK for NOS that was formed by modifying Magnusson et al.'s (1999) model. A second limitation might be related to reaching conclusions about participants' PCK from lesson plans. Some may argue that lesson plans reflect pre-service teachers' planned PCK rather than their actual PCK. Nevertheless, teacher educators have demonstrated the applicability of the lesson-preparation method (e.g., Brown et al., 2013) in investigating teachers' espoused PCK. Future studies might investigate how and to what degree the participants of this study enact their PCK in their classroom practices.

Appendix

Nancy's profile
Participant	Nancy
Topic	Particulate nature of matter
Science teaching orientation	• Science, technology and decisions • Correct explanation • Everyday coping/understand world • A structure of science • Self as explainer
SPS objectives	Absent
NOS objectives	Tentative and cumulative nature of scientific knowledge; subjectivity and creativity and imagination in science
Instructional strategy	5E (inquiry) explicit-reflective content embedded History of science
Lesson synopsis	Nancy used 5E model in her lesson planning. Throughout her planning, she stated expected student answers (ESA) to her questions and designed her instruction based on these answers. In a previous class, students learned that matter consists of mobile particles and there is space between the particles. In this class, students learnt about the states of matter. As a pre-assessment she administered 10 questions as a true–false test to students. Three of the questions were directly related to the nature of science; definitions about the phases of matter is absolute, scientists produce unchangeable knowledge since they do numerous tests, scientists claim that previous knowledge in the discipline is wrong since they do not like each other. The purpose of administering this test is to elicit students' misconception and design instruction considering students' misconception. In the engagement phase, Nancy collected the 10 questions from the true–false test and looked at them to see the students' misconceptions. She informed students that in the previous class they learned about the particulate nature of matter and in this class they would look at the subsequent developments and what questions scientists searched for the answers. She made a PowerPoint presentation on the historical development using the question–answer method. During the presentation Nancy focused on the ideas and contributions of Thales, Anaximandros, Empedocles, Aristo, Kanada, Leucippu, Democritus, Epicurus, and Lucretius. In the explanation phase, she conducted an explicit-reflective discussion on the tentative and cumulative nature of scientific knowledge. After the presentation, Nancy (N) asked “Scientists have thought and searched for the nature and states of matter throughout history. If you consider this process for producing scientific knowledge, what are the things that stood out to you? Is there only one, and only scientists have studied the nature of matter? ESA: Lots of scientists worked on the same topic. N: What else? Did any of them use the already existing knowledge in the discipline? or Did scientists start to work over? ESA: Scientists have used the previous knowledge available in the discipline produced by other scientists. N: Was the knowledge accepted as absolute or did it change over time? ESA: There was a change in scientific knowledge produced throughout history. Nancy communicated the cumulative and tentative nature of scientific knowledge and then she let the students watch a simulation of three states of matter. After the students watched the simulations, they worked in groups and drew how particles are situated in each state. Following the completion of the group work, the students presented their models by creative drama. Nancy conducted a whole class discussion on spaces among the particles and mobility of the particles in three states of matter. Also, she conducted an explicit-reflective whole class discussion on tentativeness, subjectivity and the role of creativity and imagination in science by asking the questions: “Which one of the models about the states of matter is true? One of the groups or animations? Why are there differences between the models? Did you use your creativity and imagination as well as your logic? In the explanation phase, she explained the plasma state of matter and in this way she exemplified the tentativeness of scientific knowledge. Also, Nancy described solid, liquid, and gas states of matter in detail. In the extend phase, she asked students to explain what microscopic changes occur in the particulate level when a solid becomes a liquid and then becomes a gas. Also, Nancy asked students to give examples from daily life where we can see the compressibility of gases. In the evaluation phase, she asked students to draw a concept map providing the concepts about the particulate nature of matter. Also, she asked students to prepare a poster on the areas in which the particulate nature of matter sheds light on and also, this poster had to reflect their understanding of the nature of science.
Evidence for the components of PCK and connections among them	(1) At the end of the lesson, students will be able to understand (a) the tentative nature of scientific knowledge (b) the cumulative nature of scientific knowledge (c) the subjectivity (d) the creativity and imagination in science (Lesson Plan #2, objectives, Nancy) (STO) (2) As a pre-assessment she administered 10 questions as a true–false test to the students. Three of the questions were directly related to the nature of science; definitions about the phases of matter is absolute, scientists generate unchangeable knowledge since they carry out numerous tests, scientists claim that previous knowledge in the discipline is wrong since they do not like each other. The purpose of administering this test was to elicit the students' misconceptions and to design instruction considering the students' misconceptions. (Lesson Plan #2) (KoA, KoL, KoIS) (3) Also, she asked students to prepare a poster on the areas in which the particulate nature of matter shed light on and also, this poster had to reflect their understanding of the nature of science. (Lesson Plan #2) (KoA) (4) She made a PowerPoint presentation on the historical development using the question–answer method. During the presentation Nancy focused on the ideas and contributions of Thales, Anaximandros, Empedocles, Aristo, Kanada, Leucippu, Democritus, Epicurus, and Lucretius. In the explanation phase, she conducted an explicit-reflective discussion on the tentative and cumulative nature of scientific knowledge. After the presentation, Nancy (N) asked “Scientists have thought and searched for the nature and states of matter throughout history. If you consider this process for producing scientific knowledge, what are the things that stood out to you? Is there only one, and only scientists have studied the nature of matter? ESA: Lots of scientists worked on the same topic. N: What else? Did any of them use the already existing knowledge in the discipline? or did scientists start to work over? ESA: Scientists used the previous knowledge available in the discipline produced by other scientists. N: Was the knowledge accepted as absolute or did it change over time? ESA: There was a change in scientific knowledge produced throughout history. (Lesson Plan #2) (KoIS) (5) After the students watched the simulations, they worked in groups and drew how particles are situated in each state. Following the completion of the group work, the students presented their models by creative drama. She conducted an explicit-reflective whole class discussion on tentativeness, subjectivity and the role of creativity and imagination in science by asking the questions: “Which one of the models about states of matter is true? One of the groups or animations? Why are there differences among the models? Did you use your creativity and imagination as well as your logic? In the explanation phase, she explained plasma state of matter and by this way she exemplified the tentativeness of scientific knowledge. (Lesson Plan #2) (KoIS) (6) During the lesson in which we learned how to teach about the nature of science, I learned that I can both teach chemistry and the nature of science at the same time. I will definitely not use the implicit approach since I do not think that students can learn about the nature of science by experiencing science itself. For instance, in the lesson in which we argued about misconceptions about the nature of science using concept cartoons if you did not elicit and explicitly discuss about the misconceptions they would have been changed. There should be opportunities for students where they explicitly reflect and discuss science, scientific knowledge, and scientific methods. (post interview) (KoIS) (7) It is important to elicit students' misconceptions about the nature of science for an affective nature of science instruction. If students believe that there is a universal and step by step scientific method or theories and laws do not change, my first goal should be to create a conceptual change in the students' minds instead of teaching them about what theories or laws are. After eliminating the misconceptions, the next step would be teaching about theories and laws. Students' misconceptions can be identified through the use of concept cartoons and essay type questions. (post interview) (KoL, KoA, KoIS) (8) Instead of directly telling students that their belief about the existence of a universally accepted step by step scientific method is wrong, students should live and engage in the process of science and then the teacher should conduct an explicit reflective discussion on the scientific method. (Reflection paper #5) (KoL, KoIS) (9) Concept maps, concept cartoons, and actvity sheets can be used to assess students' understanding about the nature of science. (post interview) (KoA)
	LP 2	R1	R2	R3	R4	R5	Interview
Description	After PCK for NOS	After STO	After KoL	After KoIS	After KoA	After PCK for NOS	After PCK for NOS
KoL	✓		✓			✓	✓
KoA	✓				✓	✓	✓
KoIS	✓			✓		✓	✓
STO	✓	✓		✓		✓	✓
✓ = present, O = absent; grey = missing data

Acknowledgements

This material is based upon work supported by The Scientific and Technological Research Council of Turkey 1001-Scientific and Technological Research Project Support Program under Grant 108K086 entitled Teaching the Nature of Science: Production of a professional development package for teaching scientific argumentation and reasoning based on philosophy and history of science.

Notes and references

1. Abd-El-Khalick F., (2012), Examining the sources for our understandings about science: enduring conflations and critical issues in research on nature of science in science education, Int. J. Sci. Educ., 34(3), 353–374  DOI:10.1080/09500693.2011.629013.
2. Abd-El-Khalick F., (2013), Teaching with and about nature of science, and science teacher knowledge domains, Sci. Educ., 22(9), 2087–2107 DOI:10.1007/s11191-012-9520-2.
3. Abd-El-Khalick F. and Boujaoude S., (1997), An exploratory study of knowledge base for science teaching, J. Res. Sci. Teach., 34(7), 673–699 DOI:10.1002/(SICI)1098-2736(199709)34:7<673::AID-TEA2>3.0.CO;2-J.
4. Abd-El-Khalick F. and Lederman N. G., (2000a), Improving science teachers' conceptions of nature of science: a critical review of the literature, Int. J. Sci. Educ., 22(7), 665–701 DOI:10.1080/09500690050044044.
5. Abd-El-Khalick F. and Lederman N. G., (2000b), The influence of history of science courses on students' conceptions of the nature of science, J. Res. Sci. Teach., 37(10), 1057–1095.
6. Abd-El-Khalick F. and Akerson V. L., (2004), Learning as conceptual change: Factors mediating the development of preservice elementary teachers' views of nature of science, Sci. Educ., 88(5), 785–810,  DOI:10.1002/sce.10143.
7. Abd-El-Khalick F., Bell R. L. and Lederman N. G., (1998), The nature of science and instructional practice: making the unnatural natural, Sci. Educ., 82(4), 417–436 DOI:10.1002/(SICI)1098-237X(199807)82:4<417::AID-SCE1>3.0.CO;2-E.
8. Abd-El-Khalick F., Waters M. and Le A., (2008), Representations of nature of science in high school chemistry textbooks over the past four decades, J. Res. Sci. Teach., 45(7), 835–855 DOI:10.1002/tea.20226.
9. Abell S. K., (2007), Research on science teacher knowledge, in Abell S. K. and Lederman N. G. (ed.) Handbook of research on science education, New Jersey: Lawrence Erlbaum Associates, pp. 1105–1151.
10. Abell S. K., (2008), Twenty years later: does pedagogical content knowledge remain a useful idea? Int. J. Sci. Educ., 30(10), 1405–1416  DOI:10.1080/09500690802187041.
11. Akerson V. L., Abd-El-Khalick F. S. and Lederman N. G., (2000), Influence of a reflective activity-based approach on elementary teachers' conceptions of the nature of science, J. Res. Sci. Teach., 37(4), 295–317 DOI:10.1002/(SICI)1098-2736(200004)37:4<295::AID-TEA2>3.0.CO;2-2.
12. Alters B. J., (1997), Whose nature of science? J. Res. Sci. Teach., 34(1), 39–55 DOI:10.1002/(SICI)1098-2736(199701)34:1<39::AID-TEA4>3.0.CO;2-P.
13. American Association for the Advancement of Science, (1993), Benchmarks for Science Literacy: A Project 2061 Report, NewYork: Oxford University Press.
14. Avraamidou L., (2013), Prospective elementary teachers' science teaching orientations and experiences that impacted their development, Int. J. Sci. Educ., 35(10), 1698–1724 DOI:10.1080/09500693.2012.708945.
15. Aydin S. and Boz Y., (2013), The nature of integration among PCK components: a case study of two experienced chemistry teachers, Chem. Educ. Res. Pract., 14, 615–624 10.1039/C3RP00095H.
16. Aydın S., Demirdöğen B., Tarkın A., Kutucu S., Ekiz B., Akın F. N., Tuysuz M. and Uzuntiryaki E., (2013), Providing a set of research-based practices to support preservice teachers' long-term professional development as learners of science teaching, Sci. Educ., 97, 903–935 DOI:10.1002/sce.21080.
17. Aydin S., Demirdöğen B., Akin F. N., Uzuntiryaki-Kondakci E. and Tarkin A., (2015), The nature and development of interaction among components of pedagogical content knowledge in practicum, Teach. Teach. Educ., 46, 37–50 DOI:10.1016/j.tate.2014.10.008.
18. Bell R. L., Lederman N. G. and Abd-El-Khalick F., (2000), Developing and acting upon one's conception of the nature of science: a follow-up study, J. Res. Sci. Teach., 37(6), 563–581 DOI:10.1002/1098-2736(200008)37:6<563::AID-TEA4>3.0.CO;2-N.
19. Boesdorfer S. and Lorsbach A., (2014), PCK in action: examining one chemistry teacher's practice through the lens of her orientation toward science teaching, Int. J. Sci. Educ., 36(13), 2111–2132 DOI:10.1080/09500693.2014.909959.
20. Boz Y. and Uzuntiryaki E., (2006), Turkish prospective chemistry teachers' beliefs about chemistry teaching. Int. J. Sci. Educ., 28(14), 1647–1667 DOI:10.1080/09500690500439132.
21. Brown P., Friedrichsen P. and Abell S., (2013), The development of prospective secondary biology teachers PCK, J. Sci. Teach. Educ., 24(1), 133–155 DOI:10.1007/s10972-012-9312-1.
22. Bryan L. A., (2003), Nestedness of beliefs: examining a prospective elementary teacher's belief system about science teaching and learning, J. Res. Sci. Teach., 40(9), 835–868 DOI:10.1002/tea.10113.
23. Bryan L. A. and Abell S. K., (1999), Development of professional knowledge in learning to teach elementary science, J. Res. Sci. Teach., 36(2), 121–139 DOI:10.1002/(SICI)1098-2736(199902)36:2<121::AID-TEA2>3.0.CO;2-U.
24. Burgin S. R. and Sadler T., (2016), Learning nature of science concepts through a research apprenticeship program: a comparative study of three approaches, J. Res. Sci. Teach., 53(1), 31–59 DOI:10.1002/tea.21296.
25. Campbell T., Longhurst M., Duffy A. M, Wolf P. G. and Shelton B. E., (2013), Science teaching orientations and technology-enhanced tools for student learning in science, Res. Sci. Educ., 43(50), 2035–2057 DOI:10.1007/s11165-012-9342-x.
26. Campbell T., Zuwallack R., Longhurst M., Shelton B. E. and Wolf P. G., (2014), An examination of the changes in science teaching orientations and technology-enhanced tools for student learning in the context of professional development, Int. J. Sci. Educ., 36(11), 1815–1848 DOI:10.1080/09500693.2013.879622.
27. Cavallo A., (2008), Experiencing the nature of science: an interactive, beginning-of-semester activity, J. Coll. Sci. Teach., 37(5), 12–15.
28. Cetin P. S., Erduran S. and Kaya E., (2010), Understanding the nature of chemistry and argumentation: the case of pre-service chemistry teachers, Journal of Kırşehir Education Faculty, 11(4), 41–59.
29. Chen S., (2001), Prospective teachers' views on the nature of science and science teaching, Unpublished doctoral dissertation, Indiana University, Indiana, USA.
30. Cochran K. F., King R. A. and De Ruiter J. A., (1991), Pedagogical content knowledge: a tentative model for teacher preparation, Paper presented at the annual meeting of the American Educational Research Association, Chicago.
31. Creswell J. W., (2007), Qualitative Inquiry and Research Design: Choosing among Five Traditions, London, UK: Sage.
32. Davis, E. A., (2003), Knowledge integration in science teaching: Analyzing teachers' knowledge development, Res. Sci. Educ., 34(1), 21–53.
33. Davis E. A. and Krajcik J. S., (2005), Designing educative curriculum materials to promote teacher learning, Educ. Res., 34(3), 3–14.
34. Davis E. A., Kenyon L., Hug B., Nelson M., Beyer C., Schwarz C. and Reiser B. J., (2008), MoDeLS: designing supports for teachers using scientific modeling, Paper presented at the Association for Science Teacher Education, St. Louis.
35. De Jong O. and Van Driel J., (2001), The development of prospective teachers' concerns about teaching chemistry topics at a macro–micro-symbolic interface, in Behrednt H., Dahncke H., Duit R., Graber W., Komorek M., Kross A. and Reiska P. (ed.) Research in science education: past, present and future, Dordrecht: Kluwer, pp. 271–276.
36. Demirdöğen B., Hanuscin D. L., Uzuntiryaki-Kondakci E. and Köseoğlu F., (2015), Development and Nature of Preservice Chemistry Teachers' Pedagogical Content Knowledge for Nature of Science, Res. Sci. Educ.,  DOI:10.1007/s11165-015-9472-z.
37. Dickinson V. L., Abd-El-Khalick F. and Lederman N. G., (2000), Changing elementary teachers' views of the nature of science: effective strategies for science methods curses, Retrieved from ERIC database, (ED441680).
38. Dillon J., (2009), On scientific literacy and curriculum reform, Int. J. Environ. Sci. Educ., 4(3), 201–213.
39. Dogan N. and Abd-El-Khalick F., (2008), Turkish grade 10 students' and science teachers' conceptions of nature of science: a national study, J. Res. Sci. Teach., 45(10), 1083–1112 DOI:10.1002/tea.20243.
40. Doğan N., Çakıroğlu J., Çavuş S., Bilican K. and Arslan O., (2011), Developing science teachers' nature of science views: the effect of in-service teacher education program, Hacettepe University Journal of Education, 40, 127–139.
41. Driver R., Leach J., Millar R. and Scott P., (1996), Young people's images of science, McGraw-Hill International.
42. Erduran S. and Dagher Z. R., (2014), Reconceptualizing nature of science for science education, Netherlands: Springer.
43. Faikhamta C., (2013), The development of in-service science teachers' understandings of and orientations to teaching the nature of science within a PCK-based NOS course, Res. Sci. Educ., 43(2), 847–869 DOI:10.1007/s11165-012-9283-4.
44. Fernández-Balboa J. M. and Stiehl J., (1995), The generic nature of pedagogical content knowledge among college professors, Teach. Teach. Educ., 11(3), 293–306 DOI:10.1016/0742-051X(94)00030-A.
45. Fraenkel J. R. and Wallen N. E., (2006), How to design & evaluate research in education, 6th edn, Boston: McGraw-Hill.
46. Friedrichsen P. and Dana T., (2005), A substantive-level theory of highly-regarded secondary biology teachers' science teaching orientations, J. Res. Sci. Teach., 42, 218–244 DOI:10.1002/tea.20046.
47. Friedrichsen P., van Driel J. H. and Abell S. K., (2011), Taking a closer look at science teaching orientations, Sci. Educ., 95(2), 358–376.
48. Gess-Newsome J., (2015), A model of teacher professional knowledge and skill including PCK: results of the thinking from the PCK Summit, in Berry A., Friedrichsen P. and Loughran J. (ed.) Re-examining pedagogical content knowledge in science education, New York: Routledge, pp. 28–42.
49. Grossman P., (1990), The making of a teacher, New York: Teachers College Press.
50. Hanuscin D. L., (2013), Critical incidents in the development of pedagogical content knowledge for teaching the nature of science: a prospective elementary teacher's journey, J. Sci. Teach. Educ., 24(6), 933–956 DOI:10.1007/s10972-013-9341-4.
51. Hanuscin D., Lee M. H. and Akerson V., (2011), Elementary teachers' pedagogical content knowledge for teaching the nature of science, Sci. Educ., 91(1), 145–167 DOI:10.1002/sce.20404.
52. Henze I., van Driel J. H. and Verloop N., (2008), Development of experienced science teachers' pedagogical content knowledge of models of the solar system and the universe, Int. J. Sci. Educ., 30(10), 1321–1342 DOI:10.1080/09500690802187017.
53. Irzık G. and Nola R., (2011), A family resemblance approach to the nature of science for science education, Sci. Educ., 20(7–8), 591–607 DOI:10.1007/s11191-010-9293-4.
54. Jones M. G. and Carter G., (2007), Science teacher attitudes and beliefs, in Abell S. K. and Lederman N. G. (ed.) Handbook of research on science education, Mahwah, New Jersey: Lawrence Erlbaum Associates, pp. 1067–1104.
55. Joram E. and Gabriele A. J., (1998), Preservice teachers' prior beliefs: transforming obstacles into opportunities, Teach. Teach. Educ., 14(2), 175–191 DOI:10.1016/S0742-051X(97)00035-8.
56. Kagan D. M., (1992), Implication of research on teacher belief, Educ. Psychol., 27(1), 65–90 DOI:10.1207/s15326985ep2701_6.
57. Khishfe R. and Abd-El-Khalick F., (2002), Influence of explicit and reflective versus implicit inquiry-oriented instruction on sixth graders' views of nature of science, J. Res. Sci. Teach., 39(7), 551–578 DOI:10.1002/tea.10036.
58. Kind V., (2016), Preservice science teachers' science teaching orientations and beliefs about science, Sci. Educ., 100(1), 122–152 DOI:10.1002/sce.21194.
59. Koballa T. R., Glynn, S. M. and Upson L., (2005), Conceptions of teaching science held by novice teachers in an alternative certification program, J. Sci. Teach. Educ., 16(4), 287–308.
60. Köseoğlu F., Tümay H. and Ustün U., (2010), Developing a professional development package for nature of science instruction and discussion about its implementation for pre-service teachers, Journal of Kırşehir Education Faculty, 11(4), 129–162.
61. Lannin J., Abell S. K., Arbaugh F., Chval K., Friedrichsen P. and Volkmann M., (2008), Researching teacher knowledge: further delineating the PCK construct for science and mathematics education, Paper presented at the American Educational Research Association Annual Meeting, New York, NY.
62. Lawson A., (2002), Sound and faulty arguments generated by pre-service biology teachers when testing hypotheses involving unobservable entities, J. Res. Sci. Teach., 39(3), 237–252 DOI:10.1002/tea.10019.
63. Lederman N. G., (1992), Students' and teachers' conceptions of the nature of science: a review of the research, J. Res. Sci. Teach., 29(4), 331–359 DOI:10.1002/tea.3660290404.
64. Lederman N. G., (2007), Nature of science: past, present, and future, in Abell S. K. and Lederman N. G. (ed.) Handbook of research on science education, Mahwah, NJ: Erlbaum, pp. 831–879.
65. Lederman N. G. and Abd-El-Khalick F., (1998), Avoiding de-natured science: activities that promote understandings of the nature of science, in McComas W. (ed.) The nature of science in science education: rationales and strategies, NYC, NY: Kluwer Academic Publishers, pp. 83–126.
66. Lederman N. G., Abd-El-Khalick F., Bell R. L. and Schwartz R. S., (2002), Views of the nature of science questionnaire: toward valid and meaningful assessment of learners' conceptions of the nature of science, J. Res. Sci. Teach., 39(6), 497–521 DOI:10.1002/tea.10034.
67. Lederman J. S., Lederman N. G., Bartos S. A., Bartels S. L., Meyer A. A. and Schwartz R. S., (2014), Meaningful assessment of learners' understandings about scientific inquiry—The views about scientific inquiry (VASI) questionnaire, J. Res. Sci. Teach., 51(1), 65–83 DOI:10.1002/tea.21125.
68. Liang L. L., Chen S., Chen X., Kaya O. N., Adams A. D., Macklin M. and Ebenezer J., (2008), Assessing preservice elementary teachers' views on the nature of scientific knowledge: a dual-response instrument, Asia Pac. Forum Sci. Learn. Teach., 9(1), 1–20. Retrieved at December 12 from http://www.ied.edu.hk/apfslt/v9_issue1/liang/index.htm#con.
69. Loughran J., Mulhall P. and Berry A., (2004), In search of pedagogical content knowledge in science: developing ways of articulating and documenting professional practice, J. Res. Sci. Teach., 41(4), 370–391 DOI:10.1002/tea.20007.
70. Magnusson S., Krajcik J. and Borko H., (1999), Nature, sources and development of pedagogical content knowledge for science teaching, in Gess-Newsome J. and Lederman N. G. (ed.) Examining pedagogical content knowledge: the construct and its implications for science education, Boston: Kluwer, pp. 95–132.
71. Marks R., (1990), Pedagogical content knowledge: from a mathematical case to a modified conception, J. Teach. Educ., 41(3), 3–11 DOI:10.1177/002248719004100302.
72. Marshall G. B. and Rossman C., (2011), Designing qualitative research, 5th edn, London: Sage.
73. Matkins J. J., Bell R. L, Irving K. and McNall R., (2002), Impacts of contextual and explicit instruction on preservice elementary teachers' understandings of the nature of science, Paper presented at the Annual International Conference of the Association for the Education of Teachers in Science, Charlotte, NC.
74. Matthews M. R., (1998), In defense of modest goals when teaching about the nature of science, J. Res. Sci. Teach., 35(2), 161–174 DOI:10.1002/(SICI)1098-2736(199802)35:2<161::AID-TEA6>3.0.CO;2-Q.
75. McComas W. F., (1998), The Principal Elements of the Nature of Science: Dispelling the Myths, in McComas W. F. (ed.) The Nature of Science in Science Education: Rationales and Strategies, Boston: Kluwer Academic Publishers, pp. 53–70.
76. McComas W. F. and Olson J. K., (1998), International science education standards documents, in McComas W. F. (ed.) The nature of science in science education rationales and strategies, Kluwer Academic Publishers, pp. 41–52.
77. McComas W. F., Clough M. P. and Almazroa H., (1998), The Role and Character of the Nature of Science in Science Education, in McComas W. F. (ed.) The Nature of Science in Science Education: Rationales and Strategies, The Netherlands: Kluwer Academic Publishers, pp. 3–39.
78. McDonald C. V., (2010), The influence of explicit nature of science and argumentation instruction on preservice primary teachers' views of nature of science, J. Res. Sci. Teach., 47(9), 1137–1164 DOI:10.1002/tea.20377.
79. McMillan J. H. and Schumacher S., (2001), Research in education: a conceptual introduction, 5th edn, New York: Longman.
80. Meichtry Y. J., (1993), The impact of science curricula on student views about the nature of science, J. Res. Sci. Teach., 30(5), 429–443 DOI:10.1002/tea.3660300503.
81. Mesci G. and Schwartz R., (2016), Changing preservice science teachers' views of nature of science: why some conceptions may be more easily altered than others? Res. Sci. Educ. DOI:10.1007/s11165-015-9503-9.
82. Miles M. B. and Huberman A. M., (1994), Qualitative data analysis: an expanded sourcebook, 2nd edn, Thousand Oaks: Sage Publications.
83. National Academy of Sciences, (1998), Teaching about evolution and nature of science, Washington, DC: National Academy Press.
84. Nespor J., (1987), The role of beliefs in the practice of teaching, J. Curriculum. Stud., 19(4), 317–328.
85. Next Generation Science Standards, (2013), Crosscutting Concepts. Retrieved from: http://www.nextgenscience.org/sites/ngss/files/Appendix%20G%20-%20Crosscutting%20Concepts%20FINAL%20edited%204.10.13.pdf (accessed 14.08.2015).
86. Niaz M., (2009), Progressive transitions in chemistry teachers' understanding of natüre of science based on historical controversies, Sci. Educ., 18(1), 43–65 DOI:10.1007/s11191-007-9082-x.
87. Novak J. D., (2002), Meaningful learning: the essential factor for conceptual change in limited or inappropriate propositional hierarchies leading to empowerment of learners, Sci. Educ., 86(4), 548–571 DOI:10.1002/sce.10032.
88. Ohlsson S., (2009), Resubsumption: A Possible Mechanism for Conceptual Change and Belief Revision, Educ. Psychol., 44(1), 20–40 DOI:10.1080/00461520802616267.
89. Ozgelen S., Hanuscin D., Yilmaz-Tuzun O., (2013), Preservice elementary science teachers' connections among aspects of NOS: toward a consistent, overarching framework, J. Sci. Teach. Educ., 24(5), 907–927 DOI:10.1007/s10972-012-9274-3.
90. Padilla K. and van Driel J., (2011), The relationships between PCK components: the case of quantum chemistry professors, Chem. Educ. Res. Pract., 12(3), 367–378 10.1039/C1RP90043A.
91. Padilla K., Ponce-de-Leon A. M., Rembado F. M. and Garritz A., (2008), Undergraduate professors' pedagogical content knowledge: the case of “amount of substance”, Int. J. Sci. Educ., 30(10), 1389–1404 DOI:10.1080/0950069080218703.
92. Park S. and Chen Y. C., (2012), Mapping out the integration of the components of pedagogical content knowledge (PCK): examples from high school biology classrooms, J. Res. Sci. Teach., 49(7), 922–941 DOI:10.1002/tea.21022.
93. Park S. and Oliver J. S., (2008), Revisiting the conceptualization of pedagogical content knowledge (PCK): PCK as a conceptual tool to understand teachers as professionals, Res. Sci. Educ., 38(3), 261–284 DOI:10.1007/s11165-007-9049-6.
94. Patrick H. and Pintrich P. R., (2001), Conceptual change in teachers' intuitive conceptions of learning, motivation, and instruction: The role of motivational and epistemological beliefs, in Torff B. and Sternberg R. J. (ed.) Understanding and Teaching the Intuitive Mind: Student and Teacher Learning, London: Lawrence Erlbaum Associates, pp. 117–143.
95. Patton M. Q., (2002), Qualitative Evaluation and Research Methods, 3rd edn, Sage.
96. Pintrich P. R., (1990), Implications of psychological research on student learning and college teaching for teacher education, Handbook of research on teacher education, pp. 826–857.
97. Posner G. J., Strike K. A., Hewson P. W. and Gertzog W. A., (1982), Accommodation of a Scientific Conception: Toward a Theory of Conceptual Change, Sci. Educ., 66, 211–227.
98. Putnam T. R. and Borko H., (1997), Teacher learning: implications of new views on cognition, in Biddle B., Good T. and Goodson I. (ed.) International handbook of teachers and teaching, Dordrecht: Kluwer Academic, pp. 1223–1296.
99. Roberts D. A., (1988), What counts as science education? in Fensham P. (ed.) Development and dilemma in science education, Barcecome, Lews, East Sussex, UK: Falmer Press, pp. 27–54.
100. Roberts D. A., (2007), Scientifc literacy/science literacy, in Abell S. K. and Lederman N. (ed.) Handbook of research in science education, Mahwah, NJ: Lawrence Erlbaum, pp. 729–780.
101. Sandoval W. A., (2005), Understanding students' practical epistemologies and their influence on learning through inquiry, Sci. Educ., 89(4), 634–656 DOI:10.1002/sce.20065.
102. Sandoval W., (2014), Science education's need for a theory of epistemological development, Sci. Educ., 98(3), 383–387 DOI:10.1002/sce.21107.
103. Sandoval W. and Reiser B. J., (2004), Explanation-driven inquiry: integrating conceptual and epistemic scaffolds for scientific inquiry, Sci. Educ., 88, 345–372 DOI:10.1002/sce.10130.
104. Schwartz R. S. and Lederman N. G., (2002), It's the nature of the beast: the influence of knowledge and intentions on learning and teaching nature of science, J. Res. Sci. Teach., 39(3), 205–236 DOI:10.1002/tea.10021.
105. Shulman L. S., (1986), Those who understand: knowledge growth in teaching, Educ. Res., 15(2), 4–14.
106. Shulman L. S., (1987), Knowledge and training: foundations of the new reform, Harvard Educational Review, 57, 1–22. http://dx.doi.org/10.17763/haer.57.1.j463w79r56455411.
107. Smith M. U. and Scharmann L. C., (1999), Defining versus describing the nature of science: a pragmatic analysis for classroom teachers and science educators, Sci. Educ., 83(4), 493–509.
108. Smith M. U., Lederman N. G., Bell R. L., McComas W. F. and Clough M. P., (1997), How great is the disagreement about the nature of science: a response to alters, J. Res. Sci. Teach., 34(10), 1101–1103 DOI:10.1002/(SICI)1098-2736(199712)34:10<1101::AID-TEA8>3.0.CO;2-V.
109. Smith C. L., Maclin D., Houghton C. and Hennessey M. G., (2000), Sixth-grade students' epistemologies of science: the impact of school science experiences on epistemological development, Cognition Instruct., 18(3), 349–422 DOI:10.1207/S1532690XCI1803_3.
110. Smithey J., (2003), Two perspectives on expertise in elementary science teaching, Ann Arbor: University of Michigan.
111. Tabachnick B. R. and Zeichner K. M., (1999), Idea and action: action research and the development of conceptual change teaching of science, Sci. Educ., 83(3), 309–322 DOI:10.1002/(SICI)1098-237X(199905)83:3<309::AID-SCE3>3.0.CO;2-1.
112. van Driel J. H., Verloop N. and de Vos W., (1998), Developing science teachers' pedagogical content knowledge, J. Res. Sci. Teach., 35(6), 673–695 DOI:10.1002/(SICI)1098-2736(199808)35:6<673::AID-TEA5>3.0.CO;2-J.
113. Veal W. R. and MaKinster J. G., (1999), Pedagogical content knowledge taxonomies, Electron. J. Sci. Educ., 3(4). Retrieved at April 5, 2016 from http://ejse.southwestern.edu/article/view/7615/5382/.
114. Yacoubian H. A. and BouJaoude S., (2010), The effect of reflective discussions following inquiry-based laboratory activities on students' views of nature of science, J. Res. Sci. Teach., 47, 1229–1252 DOI:10.1002/tea.20380.
115. Yin R. K., (2009), Case study research: design and methods, 4th edn, Thousand Oaks, CA: Sage.

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