In a case study, the sample size could be as small as “a person, a family, a social group, a social institution, or a community” (Best & Kahn, 1993, p.193) or “---- one group of students in a class, in one school---“ (McMillan & Schumacher, 1993, p. 375). For this study, a group of sixteen (16) Grade 10 learners at a rural high school in the Eastern Cape Province of South Africa was selected as the research participants. These learners were very familiar to each other having grown up in the same village or in adjacent villages near the school and having attended the same primary and secondary schools.
Ochs & Taylor (cited in Bricker & Bell, 2008, p. 487) claim that “environments conducive to collaborative explaining and critiquing are those marked with familiarity.” In other words, these learners would find it easy to communicate with each other in our discussions since they were already engaging in discussions with each other in their everyday lives. Other authorities, however, point at weaknesses associated with this familiarity. For example, Sarangapani (2003) in Bricker & Bell (2008, p. 487) observe that “in everyday life, if one trusts a speaker or a source of knowledge, then one will believe the claims espoused by that source of knowledge, even given slight evidence.” By extension, if one is close and familiar to another person, as was the case with my research participants, one would perhaps avoid contradicting that person for fear of spoiling their good relationship. (As will be seen in the results section of this thesis, both weaknesses referred to above did not seem to apply to this group of learners. For example, the learners quickly learnt that argumentation was not about personalities but about ideas).
Grade 10 was chosen because that is the grade where the topics lightning and thunder are mainly taught (bits and pieces of the topic are found in grades before and after grade 10) and also because the grade is under less constraints and demands from the Department of Education public examinations since such examinations can have a very significant negative impact on the implementation of a curriculum. Taba (1962), claims that: given a choice between good education and good public examination marks, many parents and students would choose good marks at the expense of good education despite the observation that “test- driven schools will not educate citizens and leaders with the experiences needed to make wise decisions in an increasingly complex, interrelated world” (Chinn, 2007, p. 1249).
Only learners who were good at English language were selected. This is because of the importance attached to language in the process of argumentation. Vygotsky (1978); Lemke (1990); and Mortimer & Scott (2003) maintain that the student should be able to use spoken and written language to articulate and defend his/her knowledge claims. The learners had to be good at science as well since we were dealing with scientific concepts. Koslowski (1996) feels that it is a prerequisite for one to know what is being talked about (the content) if one is to make meaningful arguments and come up with meaningful evidence. The quality of argumentation depends on the body of appropriate knowledge that can form the data and warrants of an individual’s arguments (Osborne, Erduran & Simon, 2004). Norris & Phillips (2003) argue that comprehending, interpreting, analysing, and critiquing (scientific) texts requires knowledge of the substantive content of science. Without this resource, constructing evidence of quality would be severely curtailed, restricted and hampered. Any learners who demonstrated considerable reticence at verbalising their thinking were not included in the study (Osborne, Erduran & Simon, 2004). Only those students who were willing to participate in the research process were selected.
From the above description, it is clear why I used purposive, information-oriented sampling (Groenewald, 2004; Flyvberg, 2006) or a deliberately selected sample (Lester, 1999) based on my judgement of the participants and on the purpose of the research. I looked for research participants who had experiences relating to lightning explanations as given by two worldviews and who were likely to be able to articulate those experiences.
What they would be involved in the study and my expectation of them during the research process was explained to the learners (See Appendices 3 & 4). The learners had to make informed decisions about whether to take part in the study or not. It was thought that informed and willing research participants would likely be more productive and come up with more reliable insights than coerced research participants.
Sixteen learners were chosen for this study because the number is large enough to allow meaningful argumentative discourses but small enough to monitor closely. The team was divided into four groups of four participants each. It was felt that a group of four would be ideal for the kind of debates and argumentation discourses the participants would go through because even if members of the group decided to team up against other members, it would likely be two against two which would still be fine for argumentation purposes. An odd
number such as three for a group could have potential problems of possible isolation of a member of the group.
Alexopoulou & Driver (1996) noted that if pupils are to scaffold each other’s learning, then the groups must be large enough to enable this to happen but small enough to allow each member of the group to have an opportunity to engage in worthwhile argumentation. In deciding on the size of the group, I was also guided by Naylor, Keogh, & Downing (2007, p. 35) who noted that
Pairs did not engage in extended discussions like the bigger groups. Lack of variety in the pupils’ views (when the pupils were too few in the group) resulted in consensus being reached quickly and the opportunities of argument correspondingly reduced. The added intimacy of a very small group might also make disagreement with the views of other group members more difficult. Whole class discussions also appeared unsuccessful in generating sustained argument by pupils.