Previous research has shown that PCK is essential for effective teaching, science teaching included (Abell, 2007; Loughran et al., 2012). The following sections present information on the role of teachers’ PCK in science teaching, how they acquire the PCK and the impact of their lack of PCK in science teaching.
2.3.3.1 Role of PCK
Shulman and Sykes (1986) described well-developed PCK as the science teacher’s ability to determine aspects of particular topics that are most difficult for learners to understand. A number of researchers have shown that PCK plays a vital role in the planning of the subject matter to be taught and learnt (Clermont, Krajcik, & Borko, 1993; Smith & Neale, 1989; Van Driel, Verloop, & De Vos, 1998). It also shapes the teachers’ acquisition of new instructional approaches and strategies (Borko & Putnam, 1996; Smith & Neale, 1989) and in the process influences the learning process (Carpenter, Fennema, Peterson, & Carey, 1988). Because PCK is subject and topic specific, teachers develop appropriate knowledge to teach the content in a particular way (Hashweh, 2005). Therefore PCK enables teachers to understand alternative ways of representing knowledge so that it becomes more comprehensible to the learners (Botha & Reddy, 2011). As a result, the teacher would identify analogies, metaphors, examples, similes, demonstrations, simulations, manipulations and the most effective communication strategies suitable for learners of particular background to understand.
Gess-Newsome (2001) viewed teachers with well-developed PCK as capable of using suitable language, behaviour and explanations, thereby making appropriate decisions in a particular science classroom setting. PCK allows effective communication with learners, which involves teachers setting up activities and questions that help learners formulate and express their own ideas, as well as listening to what learners say (Teaching and Learning Research Programme Commentary, 2010). In that way, teachers motivate learners and lead them towards ideas which are more fruitful, and as a result learners feel free to express even half-formed or confused ideas. Furthermore, Barnett and Hodson (2000) postulate that those science teachers are capable of recognising learners’ preconceptions that can be
barriers to learning and understanding. In other words, PCK enables teachers to identify conceptual difficulties that are likely to be experienced by their learners at specific points during the teaching and learning process and also design strategies on how to tackle this difficult content (Shulman, 1986, 1987).
PCK is also essential for teachers to devise and deploy the pedagogical resources appropriate to teaching a particular topic, which draws upon general pedagogical theories and takes into consideration the constraints imposed by the teaching context (Shulman, 1987). For this to happen, teacher competencies are required which Perrenaud (2000) defines as the capacity to mobilise different cognitive resources in a bid to meet a certain type of situation.
In emphasising the importance of PCK in science teaching, Ehindero (1990) asserts that a teacher’s pedagogy is influenced by the level of his PCK rather than his SMK. In agreement, Grossman (1990) asserts that PCK is the most important knowledge domain for classroom teaching. Such an assertion does not undermine the importance of SMK but gives teachers credit for their unique skills by differentiating them from scientists who are content specialists. In the same vein, Day (2001) acknowledges the importance of teachers’ PCK when he describes teachers as the most important asset in the learning society, who teach in a changing and unpredictable environment where knowledge is constructed from different sources and viewpoints.
2.3.3.2 Teacher acquisition of PCK
Shulman (1986, 1987 and 1992) formulated a Model of Pedagogical Reasoning which is a cycle of activities a teacher needs to complete for good teaching. This includes a cycle of comprehension, transformation, instruction, evaluation, reflection and new comprehension as shown in Figure 2.2. In the current study this model also explains how teachers develop their knowledge for teaching particular NS topics to learners in township schools.
Figure 2.2: Model of Pedagogical Reasoning and Action
(Adapted from Wilson, Shulman & Richert, 1987)
The cycle places teachers as continuous learners who strive to improve the teaching and learning process throughout their professional lives as they actively engage in preparing what they teach, how they teach and why they should teach in particular ways. For instance, the first stage of comprehension involves teachers conceptualising what they teach in several ways. At this stage the teachers make an effort to understand the purposes, subject- matter structures andideas within and outside the discipline (Shulman & Richert, 1987). This is followed by transformation, which is the teacher’s capacity to prepare, represent, select appropriate instructional strategies, adapt teaching materials and activities and tailor- make them to suit specific learners in the classroom (Shulman, 1987). In other words, at this stage science teachers may incorporate social constructivist views in planning the most suitable content and teaching strategies for their learners. Glatthorn (1990) elaborates the meaning of transformation as the process where the teacher fits the scientific material to the characteristics of the learners such as their ability, gender, language, culture, motivations or prior knowledge and skills. At the instruction stage pedagogical approaches such as classroom management, presentations, class and group interactions and questioning occur. At the evaluation phase teachers determine whether learners understood during the interactive teaching and at the end of lessons or units. It should be noted that the process
of evaluation is viewed as an extension of instructional process and not as a way of grading the learners (Wilson, Shulman & Richert, 1987).
The reflection stage involves teachers reviewing, reconstructing, re-enacting and analysing their practice in order to become better teachers (De Jong, 2010; Miller, 2007). Sperandeo Mineo et al. (2010) stressed the importance of reflection as a major vehicle to improve teachers’ skills when integrating the components of PCK, which include SMK and PK. Schon (1983) conceptualises two types of reflection which are reflection-inaction and reflection-on-action. Reflection-in-action refers to how teachers are taught by their own experience, and reflection-on-action refers to teachers’ deliberate review of their actions (Schon, 1983). Schon (1987) describes reflection-in-action as ‘knowing-inaction’, which is the ability by teachers to consciously think about their teaching while they are in the process of teaching. This allows the teacher to ‘think on their feet’ as they respond appropriately to an unexpected event. In distinguishing between Schon’s different types of reflection, Connelly and Clandinin (1986) interpret reflection-in-action as thinking during practice and reflection-on-action as thinking after or before practice. In this particular case the practice refers to the teaching of NS while incorporating learners’ socio-cultural practices, beliefs and experiences in some NS topics. Munby views reflection-on-action as the process by which one can learn from experience as the experience can inform the teacher on how best to teach the same concepts better in future.
Because of reflection teachers determine the reasons for success or failure of their teaching (Lucas cited in Ornstein, Thomas & Lasley, 2000), hence the stage of new comprehension, where the teacher starts the cycle all over again in a bid to improve practice. At this stage, teachers reconceptualise new and better ways of presenting their science lessons and a richer understanding of the concepts is also gained (van Driel, Verloop & De Vos, 1998). It is through such a cycle that teachers build up on their PCK (Grimmet & Mackinnon, 1992) as they develop new ways of understanding and presenting the SMK. It should be noted that in practice, the process of knowledge transformation from SMK to PCK is not unidirectional (Kinach, 2002; Sperandeo Mineo, Fazio & Tarantino, 2006) as depicted in the model above. Instead, it involves a series of backward and forward movements.
From the above model, it can be inferred that science teachers possess varying levels of PCK which continuously develop throughout their teaching career (Clement, Borko & Krajcik, 1990; Tuan, Jeng, Whang & Kaou, 1995). This means that classroom teaching experience is an important factor in enhancing teachers’ PCK (Drechsler & Van Driel, 2008). There are several key sources from which teachers can build up their PCK that include pre-service teacher training, professional development and teaching experience (Etkina, 2010; Hume & Berry, 2010; Loughran et al., 2006; Hume, 2010; Grossman et al., 2005). Teachers can also acquire PCK mainly through interaction and imitation of more experienced colleagues, reflection of one’s practice as discussed above, involvement in professional conferences, teachers’ networks and research (Barnett & Hodson, 2000; Kind, 2009a; De Jong, 2010).
2.3.3.3 PCK inadequacy in science teaching
Inadequacy in PCK can be shown by different patterns of teaching practice by science teachers. For instance, the findings of a study by Kӓpylӓa Heikkinenb Asuntaa (2008) to determine the level of PCK of primary school student teachers revealed that the participants could not select, plan and present the most appropriate content to teach as they were not knowledgeable about their learners’ conceptual difficulties.
Another example of inadequacy in PCK is shown in a study by Ramnarain and Fortus (2013) to determine South African physical sciences teachers’ perceptions of new content in a revised curriculum. The research findings revealed that a substantive number of Physical Science teachers had difficulty in conceptualising the new topics. This caused the teachers to shift their pedagogy towards more teacher-centred approaches which provided them with more authority and autonomy in managing learning (Ramnarain & Fortus, 2013). Such pedagogical practices demean the process of science teaching because the process should not be just delivery of facts and information to learners. Rather, teaching should help learners understand and be able to use and critique learnt ideas and skills as tools to gain control over real-world problems (Ball & McDiarmid, 1989).
PCK inadequacy may also be manifested in instances where science teachers fail to find meaningful examples and metaphors during the teaching process (Smith, 1987). Because
poor SMK can impact on teachers’ PCK, Lee (1995) found a science teacher relying solely on the textbook as a teaching tool and avoiding class discussions which could have given learners autonomy to explore further and ask questions. On that same note, Perrenaud (2000) found that because science, especially the physical sciences, are learnt only from textbooks, all the concepts taught often seem very far from learners’ everyday life. As a result, such teachers cannot discuss everyday life phenomena in the science classroom and relate them to scientific concepts and in the process learners’ interests to learn science are not stimulated (Perrenaud, 2000).
In summary, Shulman (1987) argues that teachers require a professional knowledge base for effective application of different methods and learning theories and principles to effectively provide comprehensive learning opportunities to learners. He postulates that this professional knowledge base comprises content knowledge, general PK, curriculum knowledge, PCK, knowledge of learners and their characteristics, knowledge of educational context, and knowledge of educational ends, purpose, values and their philosophical and historical grounds. In my study, knowledge of learners’ socio-cultural background is referred to as contextual knowledge, or CK. It is the important teacher knowledge of the teaching environment that both PCK and social constructivism emphasise in making science more comprehensible and meaningful to the learners.
The following section describes the conceptualisation of this contextual knowledge and how it impacts on science teaching and learning with reference to disadvantaged communities.