The role of teachers has great influence on student learning (Darling-Hammond, 2000; Hill et al., 2005) and therefore research studies regarding teacher knowledge and professional development of teachers become prominent (Aydın & Boz, 2012; King & Newman, 2000). Science teacher knowledge has been the focus of many researchers for more than 50 years (Abell, 2007) and among them Shulman (1986) introduced a knowledge base for teaching and called it as pedagogical content knowledge (PCK). He defined PCK as “understanding of how particular topics, problems, or issues are organized, presented, and adapted to the diverse interests and abilities of learners, and presented for instruction” (Shulman, 1987, p.8). Following Shulman’s work, many PCK models were proposed in the literature (Cochran, DeRuiter, & King, 1993; Grossman, 1990; Magnusson, Krajcik & Borko, 1999; Park & Oliver, 2008). These models differ in terms of how they conceptualize subject matter knowledge (SMK), components of PCK and relationship between them (Kind, 2009). However; Friedrichsen et al (2011) indicated that many models of PCK do not emphasize the interaction between PCK components. The present study grounded in the pentagon model of PCK which emphasizes the interplay between five components of PCK (Park & Oliver, 2008). These components are: orientation towards teaching science, knowledge of students’ understanding in science, knowledge of science curriculum, knowledge of instructional strategies and representations and knowledge of assessment. The important feature of pentagon model of PCK indicated by Park and Chen (2012) as “strong PCK has all components connected to each other strongly enough to enable the whole structure of PCK to function for scaffolding student learning” (p.926).

On the other hand, the literature reveals the scarcity of research regarding integration among PCK components (Cochran, King & DeRuiter, 1991; Grossman, 1990; Henze, van Driel, & Verloop, 2008; Kaya, 2009). Of the studies on interplay among PCK components, Park and Chen (2012) preferred to use different approach by constructing PCK maps of biology teachers to portray the interactions between components and found it as useful data analysis method to examine the nature of the interactions. Later, many researchers used PCK mapping method in their studies; however, majority of them studied with chemistry and physics teachers (Akın & Tiryaki-Kondakcı, 2017; Aydın & Boz, 2013; Aydın et al., 2015) Taking these gaps into consideration, the research question guided the current study was: “What is the nature of the integration among PCK components for three experienced science teachers in the topic of refraction of light?” The study is considered as significant for providing information regarding how components of PCK interact with each other from a holistic point of view and might provide understanding in terms of nature of PCK development of teachers. Literature calls further research regarding new methods in PCK studies (Abell, 2008) and the present study attempted to use PCK maps as an analytic tool to examine the nature of the interaction among components. Moreover, European Commission Report (2013) stated that one of the essential characteristics for teacher competencies is having deep pedagogical content knowledge and the current study also addresses European Commission’s report since implications for the nature of development pedagogical content knowledge are offered.  Lastly, since literature needs more research regarding the topic-specific nature of PCK (Abell, 2008; van Driel et al, 1998), the current study might provide information in relation to how experienced science teachers integrate the components of PCK in refraction of light topic while teaching. 

Case study, which is one type of qualitative research design, was utilized in the present study to examine the interplay between PCK components in science teachers. Case study defined as “strategy of inquiry in which the researchers explores in depth a program, event, activity, process or one or more individuals” (Creswell, 2009, p.13) and is considered appropriate for the purpose of the study. The participants of the study were three experienced science teachers and selected through purposeful sampling. Participants were in the same context. They were chosen from the same school and they had similar access to instructional material and equipment. Moreover, they taught refraction of the light topic from 6th grade elementary science curriculum at the time of study and the number of students in the observed classrooms was about 20. The participants of the current study, Carla, Sarah and Philip had 16, 21, and 24 years of teaching experience, respectively. Multiple data sources were used to capture interplay between PCK components in specific science topic. Revised form of CoRe (Aydın et. al, 2015) which includes big ideas/concepts on horizontal axis and factors that affect teachers’ decision during instruction (learner difficulties, assessment etc.) on the vertical axis was applied to participants one week before the teaching the topic. Then, two-hour lessons for each teacher were observed and follow-up interviews regarding their teaching practice were carried out. Three approaches were used in data analysis process. Firstly, for in-depth analysis, Park and Chen’s (2012) approach based on pentagonal model of PCK (Park & Oliver, 2008) was used. Based on this approach, the parts of lesson that different types of teacher knowledge influence or inform each other were determined and called as PCK episodes. Moreover, to picturize the integration of PCK components, enumerative approach was employed. Connections between components were drawn for each teacher. It is assumed that all connections have the same strength and one point was given to each of them. Frequencies of connections were summed up at the end and PCK maps were constructed for each teacher. Lastly, constant comparative method was used to identify the patterns in the integration of components. Data triangulation and methodology triangulation were used to provide evidence for credibility (Patton, 2002).

Firstly, PCK episodes were determined for each teacher to draw PCK maps. PCK episodes consisted of teachers’ and students’ roles and which PCK components were interacted in these episodes during instruction. The number of PCK episodes identified for Sarah is seven, for Philip is eight and for Carla is five during two teaching hours. While drawing PCK maps for teachers, mostly findings from observation of instruction was used but it was triangulated by the data from interviews and CoRes. PCK maps were drawn for each teacher by adding up frequencies between connections and these connections were later reflected on PCK maps. Higher frequencies indicated stronger integration in PCK maps. The main findings regarding interactions among PCK components were as follows: 1) the integrations were idiosyncratic; the nature of integrations was different for different teachers although they taught the same topic by using the same instructional materials, 2) the number of frequencies of integrations revealed both simple and complex integrations (i.e. more than two PCK components interacted in some PCK episodes), 3) knowledge of student understanding and knowledge of instructional strategies and representations were central in the integration of components in all teachers’ maps; the strength of connections between these two components were stronger when compared to other connections. It could be implied that these two components together shape PCK maps of all teachers participated in the study, 4) knowledge assessment and knowledge of curriculum had the most limited integration with the other components and they mostly connected to knowledge of students understanding component. It could be stated that these two components were less effective in shaping teachers’ PCK maps in the present study. PCK maps could be used for making comparisons between beginning and experienced teachers and teachers from different countries for making implications for teacher education in future studies.

Abell, S. (2008). Twenty years later: Does pedagogical content knowledge remain a useful idea? International Journal of Science Education, 30, 1405-1416. Abell, S. K. (2007). Research on science teacher knowledge. In S. K. Abell, & N. G. Lederman (Eds), Handbook of Research on Science Education. (pp.1105- 1151). New Jersey: Lawrence Erlbaum Associates. Akın, F. N., & Uzuntiryaki-Kondakci, E. (2018). The nature of the interplay among components of pedagogical content knowledge in reaction rate and chemical equilibrium topics of novice and experienced chemistry teachers. Chemistry Education Research and Practice, 19(1), 80-105. Aydın S., & Boz, Y. (2012). Review of studies related to pedagogical content knowledge in the context of science teacher education: Turkish case. Educational Sciences: Theory & Practice, 12(1), 479-505. Aydin, S., Demirdogen, B., Akin, F. N., Uzuntiryaki-Kondakci, E., & Tarkin, A. (2015). The nature and development of interaction among components of pedagogical content knowledge in practicum. Teaching and Teacher Education, 46, 37-50. Friedrichsen, P. M., van Driel, J. H., & Abell, S. K. (2011). Taking a closer look at science teaching orientations. Science Education, 95(2), 358–376. Kaya, O. N. (2009). The nature of relationships among the components of pedagogical content knowledge of pre-service science teachers: ‘Ozone layer depletion’ as an example, International Journal of Science Education, 31(7), 961–988 Kind, V. (2009). Pedagogical content knowledge in science education: Potential and perspective for progress, Studies in Science Education, 45(2), 169–204. Magnusson, S., Krajcik, J., & Borko, H. (1999). Nature, sources and development of pedagogical content knowledge for science teaching. In J. Gess-Newsome & N. G. Lederman (Eds.), Examining pedagogical content knowledge: The construct and its implications for science education (pp. 95-132). Dordrecth: Kluwer Academic Publishers. Park S., & Chen, Y. (2012). Mapping out the integration of the components of pedagogical content knowledge (PCK): Examples from high school biology classrooms. Journal of Research in Science Teaching, 49(7), 922-941. Park, S., & Oliver, J. S. (2008). Revisiting the conceptualization of pedagogical content knowledge (PCK): PCK as a conceptual tool to understand teachers as professionals. Research in Science Education, 38(3), 261–284. Patton, M. Q., (2002). Qualitative research and evaluation methods. 3rd edt. Thousand Oaks, California: Sage Publications, Inc. Shulman, L. S. (1986). Those who understand: Knowledge growth in teaching. Educational Researcher, 15, 4-14. Shulman, L. S. (1987). Knowledge and training: Foundations of the new reform. Harvard Educational Review, 57, 1-22.