CONCLUSIONES :

There has been an increased awareness in determining the effectiveness of argumentation in enhancing teachers’ and students understanding of the Nature of Science. (e.g., Ogunniyi 2004, 2006, 2007 a & b; Ogunniyi & Hewson, 2008; Erduran et al, 2004; Naylor, Downing, Keogh, 2001, Simon et al, 2006). Ogunniyi & Hewson, (2008) indicate the fact that numerous studies have shown the significance of dialogic argumentation as a valuable instrument for teachers’ and learners’ conceptual understanding as well as making them aware of the tentative and material- discursive nature of science construction.

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The degree to which children learn to engage in discussion and use evidence in science is important for future decision-making, especially in the context of socio-scientific issues (Ratcliffe & Grace, 2003). Toulmin’s (1958) Argumentation Pattern (TAP) has been used by several researchers to improve educators’ and learners’ understanding of the Nature of Science (e.g. Kelly & Bazerman, 2003; Kelly & Takao, 2002; Osborne et al, 2004; Erduran et al, 2004; Jimenez-Aleixandre et al, 2000). According to Ogunniyi & Hewson (2008:161)

TAP consists of such elements as:

1.Claim-The statement that is asserted or declared as the truth of a subject matter e.g. the liquid in the glass is water. However, we would not be certain of how truthful this statement is until we have carried a scientific test. In other words, we need more data.

2. Data-The evidence gathered from our observational or experimental testing or the reason we use to confirm the truth of the assertion.

3. Warrants-The justification which links the claim with the evidence. 4. Backing- The underlying assumptions on which the claim is based. 5. Qualifiers- The conditions binding the claim.

6. Rebuttals-The statement that contradict the claim (Simon et al, 2006).

Some scholars e.g. Erduran et al, (2004) have modified Toulmin’s framework to determine students’ use of rebuttals in-group work. Due to the complex nature of TAP and the overlap of its constituent elements, they have combined data, warrants and backings into “grounds”. A good argument in their opinion is based on two assumptions: (1) the grounds, which include (data, warrants and backings) to verify the claim, and (2) arguments with rebuttals are of better quality than those without. Ogunniyi (2009) has further modified TAP as espoused by Erduran et al (2004). See Table 2.1

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Ogunniyi (2004) Levels of Toulmin’s Argumentation Pattern Quality Characteristics of an argumentation course

Level 0 Non – oppositional

Level 1 Argument involves a simple claim versus counterclaim with no grounds or rebuttals

Level 2 Argument involves claims or counterclaims with grounds but no rebuttals. Level 3 Argument involves claims or counterclaims with grounds but only a single

rebuttal challenging the claim.

Level 4 Argument involves multiple rebuttals challenging the claim but no rebuttal challenging the grounds (data, warrants and backing) supporting the claim. Level 5 Argument involves multiple rebuttals and at least one rebuttal challenging the

grounds.

Level 6 Argument involves multiple rebuttals challenging the claim and /or grounds.

Table 2 1 Source: Ogunniyi (2004) Levels of Toulmin’s Argumentation Pattern

Prior studies have shown that school teaching spent limited time on developing skills which are of utmost importance for learners to construct scientific arguments (Maloney & Simon, 2006). This statement resonates with my own experience. Educators who have not been trained on argumentation will find it immensely difficult to try this approach in class. Schools that are under staffed cannot do justice to the science curriculum because educators who are not qualified to teach science, are teaching it.

Besides, many of them have limited subject matter knowledge to use a dialogical argumentation instruction. According to Andriessen (2006) argumentation in science is not oppositional and aggressive. It is an outline of collaborative debate in which both parties are working together to unravel an issue through common agreement. He further more argues that collaborative argumentation must not be competitive, as this will prevent learning taking place in a systematic way.

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Perelman (1979) claims that criticism and justifications are important during argumentation, and that an individual will not be capable to understand an argument correctly if he/she is not certain about what the argument is all about. Kelly et al., (1998) states that several researches have experienced problems in using TAP to determine the construction and components of an argument, whereas Erduran et al. 2004; Jimenez Aleixander & Pereiro-Munoz, 2005 claims that other researchers have found it valuable as an logical devise to relate to classroom dialogue.

Simon et al. (2006) points out that the ability to understand and follow arguments of a scientific nature is a critical part in scientific literacy in its basic sense. Erduran et al (2004) claims that argumentation is an effective tool for teaching science. Kuhn (1992, 1993a) state that science taught through argumentation enhances scientific thinking in young children. However, useful as TAP is in analyzing claims, counterclaims and rebuttals made by people, it does not address arguments that attempt to describe human experience and socio-cultural issues and beliefs not easily amenable to formal deductive-inductive logic.

Often, the values that people associate with certain cultural beliefs and symbols, which in certain respects are legitimate and meaningful, may lack strict empirical validity. Also, as learners move from their traditional communities into the science classroom, they are likely to encounter conflicts of ideas and values which in turn may predispose them to develop positive or negative attitudes towards school science. To get along with school science they have to shift from one cognitive state to another. The reverse is probably true as they return from school to their home environment. It is in this context that the Contiguity Argumentation (CAT) seems to be more appropriate than TAP.