Teachers face and partially overcome challenges when mediating chemical equilibrium concepts
Researchers such as Chiu, Chou and Liu (2002) and Rudd, Greenbowe and Hand (2007) agree that the chemical equilibrium topic is challenging and difficult for both teachers and learners. There are several factors, which are associated to the problems encountered when mediating this topic. In agreement with literature, my findings reveal that there were numerous challenges experienced by both teachers and learners during the mediation of chemical equilibrium. Tyson et al. (1999) suggest that the concepts are difficult to comprehend because they are abstract in nature. Mrs Focus concurred that the topic is ‘conceptually really tricky’ and ‘it is ‘really abstract’. In agreement with Tyson et al. (1999) and Rollnick et al. (2008), she cited the concept reversibility of reactions to be a problem for learners. In the pre-interview, Mrs Focus mentioned that learners found it difficult to understand ‘the idea that a reaction can go either
way’. However, during my lesson observations, there were few difficulties with understanding
reversibility of reactions. I postulate that Mrs Focus had modified her teaching in such a way as to eradicate the problem. In other words, the knowledge of learner difficulties helped her to mediate effectively. Shulman (1987) posits that to facilitate learning, teachers must understand learner difficulties.
Although the learners easily grasped reversibility as a separate concept, they struggled to distinguish equilibrium from reversibility. Tyson et al. (1999) explain that there is a subtle difference between some chemical equilibrium ideas. This leads learners to draw wrong
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conclusions. To overcome this challenge, Mrs Focus used an analogy of public speakers who were dynamic at assembly. She then explained the meaning of dynamic equilibrium.
In both Mr Humour’s and Mrs Focus’ lessons, I found that learners initially had difficulty with applying Le Chatelier’s Principle (LCP) to predict the effect of changes in equilibrium
conditions. Mrs Focus stated in both her interviews that learners found the effects of altering pressure to be particularly difficult.
Mr Humour attributed some of the learner difficulties to the wording of LCP. He thought it was complicated and only accessible to ‘good English speakers’. Similarly, Mrs Focus introduced the principle by saying ‘Le Chatelier put forward a proposal… so I am going to be very plain with
it, I am not going to use it verbatim at the moment’. Interestingly, Mr Humour also simplified the
principle first before stating it fully. The teachers’ actions converged with Quilez (2004) who motivates that the vocabulary used in the principle is vague and incomprehensible.rs F
Additionally, there were instances when the learners made inaccurate predictions during lessons by applying the LCP. They would confuse which reaction would be favoured or which way the equilibrium would shift. This finding is consistent with authors such as Voska and Heikkinen (2000), Kousathana and Tsarpalis (2002) and Cheung (2009). These researchers advise that LCP may result in erroneous predictions when answering chemical equilibrium questions.
The teachers dealt with challenges associated LCP and the changes in conditions at equilibrium in various ways. Firstly, both teachers mentioned that repetition helped the learners understand. In the stimulated recall interview, Mrs Focus emphasised that when she started the topic few learners grasped the ideas but through repetition, other learners were able to understand.
Secondly, the teachers made the learners carry out various written exercises to help them to clear up misconceptions. They revised the questions in class and the learners made the necessary corrections. Thirdly, both teachers utilised the question and answer method to deal with problems. The teachers would ask the students leading questions or probe until they realised their mistakes. The learners themselves would be encouraged to ask questions if they had any misunderstandings. The teachers responded to learners’ enquiries as best as they could. In addition, Mrs Focus relied on ‘drilling’ the learners. This approach made the learners ask themselves questions on the procedure to follow. In other words, the learners were taught the pathway to follow when making predictions. For example, for changes in conditions of systems
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at equilibrium, the learners were encouraged to ‘first determine what LCP would say’, determine which reaction would be favoured and then predict the changes in concentration.
Mrs Focus felt that this systematic approach to answering questions was the reason why her learners performed well in examinations. Similarly, the Examiners’ reports encourage teachers to use past examination questions as teaching resources to improve how students answer questions.
The equilibrium constant calculations proved to be problematic for learners. In the interviews, Mrs Focus and Mr Humour expressed opposing opinions concerning mathematical problems. Mrs Focus said ‘calculations are not a problem’ while Mr Humour mentioned that ‘’let’s say
you try to do calculations, student’s struggle with calculations’. However, Mrs Focus conceded
in the SRI that when working out the equilibrium constant, some learners would add up the concentrations of reactants instead of multiplying. Others would forget to include the coefficients in their equilibrium expression. Voska and Heikkinen (2000) acknowledge that learners experience problems with the mathematics involved in equilibrium. On the other hand, Tyson et al. (1999) insist that using mathematical formulations such as the equilibrium law eliminates incorrect predictions. My findings disagree with Tyson et al. (1999). Mathematical difficulties would limit learners’ ability to use the equilibrium law.
The teachers tried to reduce mathematical errors by exposing the learners to numerous examples. These were worked out in class and as homework. Mr Humour drew on learners’ prior
knowledge of indices. When he started the section on deducing the units of the equilibrium constant, he did not mention indices. After realising that the learners were struggling, he went back to the laws of indices. Immediately, the learners began perform the calculations correctly. This shows that the teachers must integrate knowledge from other disciplines when mediating learning. At the same time, it affirms Roschelle’s (1995) idea that learning will not be possible if teachers ignore learners’ prior knowledge.
Furthermore, Mrs Focus had trouble with teaching chemical equilibrium concepts at the
beginning of her career. She admitted to ‘not fully understanding’ the topic. This is in agreement with studies by Cheung (2009) and Quilez (2004) who found that teachers in Hong Kong and Spain respectively, held numerous misconceptions related to chemical equilibrium. Coherently, Rollnick et al. (2008) mention that teachers struggle with teaching the topic because of limited SMK.
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A number of factors enabled Mrs Focus to improve on her mediation. She observed more experienced teachers. On that matter, she said ‘I remember frequently sitting in one teachers’
lessons in particular’. Mrs Focus read extensively around the topic developing her SMK. .As
she gained more teaching experience, she found it easier to teach the topic. This finding agrees with Schulman (1987) who proposes that more experienced teachers possess more advanced PCK.
5.5 Analytical Statement 4:
The development of a chemical equilibrium module can help improve the way teachers scaffold learning
In the second phase of my study, I co-developed a chemical equilibrium module with my research participants. The aim was to develop a unit of work to support teachers with the mediation of chemical equilibrium concepts.
We compiled the module based on data generated during my study. The unit of work integrated the best practices observed in the teachers’ lessons such as analogies as well as the specific areas which teachers indicated that they needed added support.
The teachers felt we needed to include as many practical activities as possible in the module. They reasoned that practical activities would improve participation of learners and enhance knowledge construction as proposed by Maselwa and Ngcoza (2003). To this end, we used the internet to look for suitable investigations to include. Unfortunately, most of the practical activities we came across were ‘recipe type’ practical work. This upholds Hodson’s (1990) notion that most practical work is prescriptive and of no educational value. We found no other source of practical activities besides the internet.
In the module, we added more links to YouTube clips. Both teachers expressed a desire to have more visual aids. The practice concurs with Van Driel (2002) proposal that learners should view abstract chemical equilibrium phenomena to reduce misconceptions.
We retained the questions in the teachers’ resource as we felt they were a good balance of factual recall and cognitively challenging problems. The aim was to use the questions to provide a scaffold for learners in their ZPD. Goos (2004) maintains that scaffolding should occur in the ZPD for learning to take place. The learners would move from the simple questions that they
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could do on their own to the more complex ones to be answered with the assistance of the teacher.
In the teaching module, I included the game on chemical equilibrium that I pilot-tested with the Masters and BEd (Hons) Science Elective students studying at Rhodes University. I shared the game with my research participants who gave it their learners to play in groups. The learners formulated their own conclusions from the results. The learners were keen to play the game and took control of all the proceedings. McRobbie and Tobin (1997) argue that learners must be actively involved during learning because it enhances conceptual understanding. They advocate for learner autonomy during lessons to promote learner motivation.
The learners worked in groups in line with Vygotsky’s (1978) social constructivism. The theory advances that social interactions are crucial for learning. In adherence, Hodson and Hodson (1998) explain that cognitive development is a direct result of learners co-constructing
knowledge. In this way, social constructivism reduces rote learning leading to better conceptual understanding.
The inclusion of the practical activities, whole class discussions and equilibrium game is in line with MEC (1993) learner centred education (LCE). The approach places the learner at the centre of education. Learner centred teaching methods such as discovery learning is preferred to
traditional strategies.
The teachers felt that developing the module was beneficial to all of us as we were able to share our expertise. The teachers found the exercise so constructive that we went on to set some dates to develop modules for other topics. Mrs Focus acknowledged that
“It is an excellent idea, just using expertise from different people and everyone has
personally has a slightly different understanding and putting it together makes for a really good process. It is the right way to do it”.
This experience is consistent with the ideas of Thompson, Gregg and Niska (2004) ideas who propose that when teachers solve a problem as a team, they benefit immensely and this, in turn, spills over to their learners. Thus, as teachers exchange information through collaborations, their performance is improved (ibid.). This is in agreement with Lave and Wenger (1991) who encouraged members of communities to work together for maximum achievement.
87 5.6 Concluding remarks
In this chapter, I discussed and interpreted my data gathered from document analysis, interviews and lesson observations. I constructed four analytical statements from my data presented in Chapter 4 as these answered my research questions.
In summary, I found that teachers and learners experience the topic of chemical equilibrium as a difficult one. The teachers drew on meditational tools and PCK to provide a scaffold for learners to make sense of chemical equilibrium concepts. They relied mainly on language, prior
knowledge, lecture method, question and answer approaches and the equilibrium hand out. However, their use of practical activities and social constructivist teaching strategies were limited.
Furthermore, the teachers in this study encountered a number of challenges during the mediation of learning. These centred on language, making predictions for systems in equilibrium and calculation of the equilibrium concept. The teachers partially overcame some of the challenges by repetition and correction of misconceptions as they unfolded. To support teachers with this topic a module was co-developed with the two teachers.
In the next chapter, I present a summary of my findings and make recommendations for areas for future research as well critically reflect on my research journey. Finally, I present the
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Chapter 6
Summary of findings, recommendations and conclusions
In this section, all loose ends should be gathered together. This is the place for looking backward, for distilling into a few paragraphs what has been achieved in each phase of the research activity (Leedy & Ormrod, 2014, p. 329).
6.1 Introduction
The main aim of this study was to understand how Grade 11 Physical Science teachers mediate learning of the topic chemical equilibrium. My experiences as a Physical Science teacher as well as a National Examiner marker motivated my study. I gained some useful insights on how teachers use meditational tools to provide a scaffold for learners, the teaching strategies they employ, challenges that arose and ways in which the teachers dealt with these challenges. In this chapter, the findings of my research, limitations and the resulting recommendations are summarised as described by Leedy and Ormrod (2014) in the epigraph. The recommendations suggest ways to potentially improve how teachers mediate learning of the topic chemical
equilibrium. At the end of the chapter, a critical refection of my research journey is outlined and this is followed by the conclusions drawn from the study.