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Effective teaching strategies and use of LTSM enables learning of stoichiometry

According to Sedumedi (2014, p. 1346), “Teaching in general and science teaching in particular is a complex process with unpredictable outcomes”. Thus, teachers opt for different teaching methods in order to deal with this challenge (ibid). For positive teaching outcomes one has to opt for the best teaching method for an effective mediation process. In the following sections I discuss the different teaching strategies and learning and teaching support materials (LTSMs) that were used to scaffold stoichiometry.

5.4.1. Lecturing and questioning

The lessons for the two participating teachers in this study were dominated by the lecturing method which falls under a teacher-centred teaching strategy. During the lessons the teachers provided most of the information to the learners as opposed to the learner-centred approach which is underpinned by the constructivism theory of learning. During the lecturing, the learners were observed listening and copying whatever the teacher wrote on the chalkboard, and no active participation in the learning process was observed. Hence, the lecturing method did not promote conceptual understanding of stoichiometry; instead it only promoted memorisation of facts and rote learning. According to Schuh (2004), lecturing does not give learners an opportunity to fully grasp the information provided to them by the teacher. Thus, they cannot construct their own knowledge.

Although the curriculum documents advocate the use of a learner-centred approach to teaching and learning, the teachers in this study defended their use of teacher-centeredness

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during the stimulated-recall interviews arguing that the topic is too abstract and most of the concepts used in the topic are new to the learners. This however contradicts what the teachers said during the pre-interviews that the stoichiometry topic is not completely new as some of its aspects have already been covered in previous grades like writing formulas and balancing equations. Hence, the teachers’ use of the lecturing method could mean that they did not take the learners’ prior knowledge into account.

In addition to lecturing which I feel is a less effective method to mediate learning, the teachers also used the questioning strategy to scaffold the learners. According to Chin (2007), questioning is the key component classroom talk and can contribute to effective mediation of learners’ knowledge construction as it can arouse their thinking.

The teachers in this study used both written and oral questions. The oral questions were however more closed questions and these were in most cases answered in chorus so these types of questions could not develop learners’ cognitive skills. Furthermore, most of the questions were simply meant to assess what the learners’ knew.

By determining what the learners know, the teacher can determine where they are within the Zone of Proximal Development (ZPD). The ZPD is the distance between what a learner can do with and without help from the teacher (Vygotsky, 1978). When the level of ZPD is determined the teachers can then properly scaffold the learners. According to Goos (2004), the ZPD can be set up through scaffolding and collaboration.

The written questions were answered by the whole class and some were done as individual work. The teachers first guided the learners on how to solve the problems and thereafter let them work on their own after determining that they had reached a point where they could proceed on their own.

5.4.2. Collaboration and group work

The lessons for the participating teachers were supplemented with collaboration and group work. Davis (1999) asserts that working in groups helps the learners to master the content and promotes critical thinking. During group work learners are actively involved in the lesson and can learn from one another as they interact in the groups. Letting learners work in groups as Teacher 1 did in Lesson 4 was a good method to encourage the learners to interact with one another. Learners who could not understand the content during the teacher’s instructional teaching were able to ask others and be helped by others in the groups.

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Although Teacher 2 did use formal groups in his teaching, learners discussed with one another when given activities to do. Learner-learner interaction shapes a collaborative ZPD. In addition, during group work and individual activities the teachers moved around from one group to the other to assess the group’s progress and performance. I found that helping learners in small groups like this more effective than working together in one large group. The use of collaboration and group work is in line with the learner-centred approach to teaching in which learners are the centre of the learning process. A learner-centred approach is central to a constructivism classroom in which learners interact with one another. Additionally, Moll (2002) posits that meaning can be constructed through collaboration

5.4.3. Use of a chalkboard

The two teachers made use of chalkboards as a one of the LTSMs during their teaching. The chalkboard was used for different purposes including: writing notes, writing new concepts, solving problems and giving feedback on the given activities. All this made the chalkboard a great tool for teaching as it can be used as a visual teaching aid. Learners had the chance to see or visualize what the teacher was saying.

Probyn (2005) supports the use of the chalkboard in teaching as in promotes language development of the learners. The teachers in this study constantly wrote the new concepts and their meanings on the chalkboard which is a good move especially when working with the learners whose first language is different from the language of teaching and learning as was the case with the two teachers. These teachers also wrote the equations used in calculating different quantities on the chalkboard which is good if they are well explained. For instance, Teacher 1 explained how using proportionality formulas came about and this gave the learners a deep understanding of the concepts unlike Teacher 2 who just wrote the formulas on the chalkboard without any explanation. Using Teacher 2’s approach promotes rote learning which is in conflict with the constructivist theory.

Furthermore, the chalkboard was also used as an interactive resource (Probyn, 2005) where for example, Teacher 1 gave the learners an opportunity to solve problems on the chalkboard. During this time the learners also acted as peer teachers as they were given the chance to explain to the whole class. This approach not only motivated the learners but also helped the teachers to assess the learners’ understanding.

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Furthermore, in giving the learners an opportunity to act as peer-teachers, the teachers promoted collaboration, an aspect that Vygotsky regards as vital in the ZPD theory. Goos (2004) posits that peer interaction gives learners an opportunity to evaluate their understanding. Goos adds that during collaboration teachers’ effort is still crucial. In other words, the teachers still need to facilitate the collaboration process and give support to the learners. As the learners were explaining the teacher kept prompting the learners with questions so they could elaborate further.