The effect of an argumentation-based instruction on Grade 11 learners' understanding of chemical reactions used in extracting gold

Abstract

This purpose of this research study was first, to identify some of the many conceptual problems that science learners have. An area that students generally find difficult according to a plethora of studies is chemical reactions. In the light of the new curriculum stressing the need for learners to know about the application of chemistry in industries, the extraction of gold being one of them, I decided to select this topic as my study focus for two reasons: (1) knowledge about the methods used in the extraction of gold is particularly useful for learners to learn in that gold is the leading mineral exported by South Africa.; and (2) learners find the chemical processes involved in the extraction of gold particularly difficult. It is perhaps for the same reasons why this topic is in the curriculum. Specifically, this study focused on determining: (1) Grade 11 learners' conceptions of chemical reactions and in particular, the extraction of gold; (2) whether subjects exposed to an argumentation-based instruction would hold more valid conceptions of chemical extraction of gold than those not so exposed; and (3) whether or not the subjects' conceptions of chemical extraction of gold are related to their age, gender and socio-economic backgrounds. This study was underpinned by Toulmin's (1958) Argumentation Pattern (TAP) and Ogunniyi's (2007a) Contiguity Argumentation Theory (CAT).These two theoretical frameworks were used to elicit and address the learners' scientific and indigenous knowledge conceptions of chemical reactions with respect to chemical reactions used in the extraction of gold. The study was based on a quasi-experimental pre-post-test control design depicted as follows: The pre-test was administered simultaneously to both the experimental and control groups. The experimental group was then exposed to the argumentation-based instruction underpinned by TAP and CAT alluded to earlier, while the control group was exposed to traditional expository instruction. It was after this that the post-test of Chemical Reactions Questionnaire (CRQ) was simultaneously administered in both the experimental and control groups. The data collected through the questionnaire and interviews were analyzed and described both quantitatively and qualitatively. The study confirmed that many learners had misconceptions. These include: failing to recognise everyday reactions as in fact chemical reactions; misconceptions in reaction rates; exo- and endothermic reactions; balancing of equations; precipitation reactions; oxidation number changes and hence oxidation -reduction misconceptions. Many learners' also displayed a lack of terminology and the correct usage of science terms. The study showed that the argumentation-based instruction underpinned by TAP and CAT used in the experimental group was more effective in enhancing Grade 11 learners' understanding of chemical reactions involved in gold extraction than was the case in the control group where learners were exposed to traditional expository instruction. The finding has thus confirmed earlier studies using similar argumentation based instruction (e.g. Erduran, et ai, 2004; Simon, et ai, 2006). The study also seemed to have increased the learners' knowledge and awareness about the industrial and indigenous methods of extracting gold than was previously the case. However, the study did not reveal much conceptual differences among the learners in both groups on account of differences in their gender, age or socio-economic backgrounds. Despite the generally poor socio-economic background of many learners in the experimental group they became particularly fascinated with the argumentation-based instruction and indicated that the approach had enhanced their interest in studying science and in pursuing science-related careers. Overall, the study seemed to have confirmed earlier findings that: (1) an argumentation-based instruction was not only feasible in the classroom but also effective for enhancing learners' understanding the concept of chemical reactions; (2) teachers could be trained as I was, to implement an inclusive science-indigenous knowledge curriculum, thus making school science relevant to learners' socio-cultural environment (e.g. Ogunniyi, 2007a &b).