1.! Análisis del Instrumento de diagnóstico

Every study is guided by belief systems which are based on epistemological, ontological and methodological assumptions (Guba & Lincoln, 1994). It is through these assumptions that the methodology of the study is informed and in turn the interpretations of the findings are shaped (Crotty, 1998). The researcher’s views about reality, the nature of knowledge, how knowledge is constructed and how knowledge is achieved are briefly discussed in this section.

The study is guided by the social constructivist epistemological view that knowledge is not discovered, but is constructed within the minds of the individuals through social interactions as discussed in Chapter Two, which Crotty (1998) also referred to as constructionism. Therefore knowledge construction involves the socialisation of individuals into the practices of the communities in which they are embedded (Park, 2005) and these communities have their own ways of validating their knowledge claims.

meaning from the same phenomenon can be constructed in different ways by different people. An individual is not a passive recipient of meaning but is an active, resourceful and reflecting participant during the process of constructing meaning. Since this study is based on the constructionist epistemology which assumes that in order to understand an individual’s interpretations of reality, one has to understand the particular social contexts within which they operate (Mertens, 1998), details of the participants’ background and context within which they work (research setting) are discussed.

The study focused on the interaction between the teachers and learners in the science classroom while exploring the teachers’ CK, the different ways in which they incorporated the CK in some NS topics and how that CK influenced the teachers’ PCK. This is because knowledge construction can either be encouraged or constrained by social interactions (Driver, Asoko, Leach, Mortimer, & Scott, 1994). Therefore the study is influenced by Searle’s (1995) ontological view that reality is socially mediated. In other words, individuals construct reality through their personal experiences within their social context. The study therefore took the stance that constructivism and realism are compatible (Crotty, 1998). In this case, realism is viewed as the belief that the external world can exist independent of our representations of it (Searle, 1995). From a broader perspective, the study acknowledges that both knowledge and reality are manifestations of the social constructions of individuals living in a particular social community.

3.5 Research design

The study employed a qualitative case-study research design. Qualitative research is a naturalistic approach that seeks to understand phenomena in context-specific settings, where the researcher does not manipulate the phenomenon of interest (Patton, 2002) but probes for deeper understanding rather than examining surface features (Johnson, 1995). Previous research studies in education have used case-study research design more to explore the processes and dynamics of practice (Merriam, 1988; 1998) in order to shed light on a phenomenon, the process, events, persons or things of interest to the researcher (Gall, Gall & Borg 1996). Therefore, the main characteristic of qualitative research is its focus on the intensive study of specific instances – cases of a phenomenon. For this reason,

the current study is a qualitative case-study research that allows an in-depth exploration of classroom practices, using multiple forms of data collection (Creswell, 2005).

A qualitative case-study methodology (Gall, Gall & Borg & 1996; Merriam, 1988; 1998; Stake, 1994) was therefore used to conduct an exploratory study of Grade 9 NS teachers' CK and how it influences their PCK when teaching in a township school environment. A qualitative case-study approach evolves from the notion that detailed case studies of teaching using observational and interview procedures result in well-documented and insightful accounts of teachers’ thoughts and practices (Calderhead, 1996). A qualitative case study enabled the researcher to make an exploration and description of the knowledge that NS township teachers had about their learners’ socio-cultural background, that is the teachers’ contextual knowledge and how that knowledge impacted on teachers’ practice (Yin, 2003). This design is suitable for the current study because case studies are based on the constructivist premise that knowledge and reality are a social construction (Searle, 1995) as explained in section 3.4. In this study the qualitative case-study design allowed close collaboration between the researcher and teachers which made it easier for the researcher to understand and interpret the teachers’ actions (Robottom & Hart, 1993). The study’s expectations were that the teachers’ CK (knowledge of learners’ socio-cultural background) should enable teachers to present science concepts in a more comprehensive manner that makes the learners understand better. This methodology allowed the researcher to gain an in-depth understanding of the role of CK in PCK of Grade 9 NS teachers, how these teachers perceive the importance of CK in science teaching as well as identifying the teaching strategies and practices fostered in such contexts.

Qualitative methodologies allow for deeper comprehension and exploration of classroom situations in an exact manner rather than based on speculations (Merriam, 1998). The methodology enabled the researcher to capture the teachers’ experiences in the science classroom, which included the planning process, interaction and engagement with learners during lesson presentation, to show the complexities of teaching and learning science in a township school. Qualitative case-study approach was appropriate because the interest of the study was in the process rather than outcomes, in context rather than a specific variable and in discovery rather than confirmation (Merriam, 1998).