Keith S.
Taber
Faculty of Education, University of Cambridge, Cambridge, UK. E-mail: kst24@cam.ac.uk
Chemistry education research (CER) however has not traditionally enjoyed support for research-for-its-own-sake enquiries. In part this reflects the kinds of academic area education is – an inherently applied field of work. Arguably chemistry education is more akin to chemical engineering than pure chemistry in this sense – where researchers are expected to work on problems that have been identified as having clear relevance to practical concerns. As educational research generally has potential to inconvenience teachers and learners, and indeed even disrupt normal educational activity, there is often also a strong ethical basis for not undertaking research on something ‘just to see what would happen if’ for no better reason than our natural curiosity (see the editorial in CERP15(2) (Taber, 2014)). Rather programmes of research are expected to respond to well recognised issues and challenges in teaching and learning. So we should expect research to have effects on practice.
The national educational research association in the UK, responding to the inclusion of evidence of research impact in national evaluations of research undertaken in the universities refers to “how education impacts on everyone and how a strong research discipline can ensure that individual lives and communities are transformed through education” (British Educational Research Association, 2013, p. 4). This raises the questions of both how we know research has impact at the level of teaching and learning, and indeed how this happens, given that:
What we know for sure is that educational research generally does not have an immediate impact on policy or practice; indeed it may take many years for the insights from research to filter through. Unlike some areas of research that have the potential to impact on society, it cannot be represented or distilled into simple one line actions. It needs to be interpreted and mediated in a variety of processes to accommodate different circumstances (Gardner, 2011, p. 559).
I am extremely privileged to have been supported by the RSC to undertake work that was directly designed to help teachers access and apply research – through one of a number of annual teacher fellowships that were awarded for projects considered capable of supporting the teaching of chemistry at school or college level. (In the UK references to college level usually mean students in pre-university courses.) My project concerned the development of classroom materials to help teachers identify and so challenge students' alternative conceptions (‘misconceptions’) in core areas of chemistry. The RSC not only supported this project by funding my release from all other academic responsibilities for a full academic year (during which time the project was hosted by the University of London Institute of Education) but though a commitment to widespread dissemination of the outcomes. Two A4 sized books on ‘Chemical Misconceptions’ (Taber, 2002a, 2002b) were published and sent at the RSC's expense to secondary schools, further education colleges and university teacher education departments nationally. Moreover, the classroom materials themselves have been made available free from the RSC's website as electronic downloads both as pdf files and as editable word-processing files.
Of course, making resource-informed materials available does not necessarily lead to uptake. Teachers may be too busy to properly evaluate materials and consider how they might integrate them into teaching. Moreover, research-informed resources only lead to research-informed practice when they are used in ways consistent with the original intention. Too often such materials may be adopted without the perspective from within which they were designed – especially when there is no ongoing professional development support. These particular materials were designed to support teachers in applying an approach to teaching (one book provided the background, drawing extensively upon ideas and examples from chemistry teaching and learning; the other book provided a set of classroom activities, that were each accompanied by teacher guidance) but it is known that teachers can be very good at dissecting activities from their intended pedagogic contexts and then fitting them into existing ways of teaching. For example, the diagnostic materials were not intended – nor in general were they especially suitable for – use in summative assessment, but there was nothing to stop teachers using them as end-of-topic tests.
With many projects the researcher (or resource developer) does their work, distributes it (or often simply makes it available and hopes the target audience find it), and then trusts it may be taken up – and will have an effect. Anecdotal evidence from chance meetings and the like may reinforce an impression that there has been impact, but unless the work is linked with or adopted into some major national initiative it may be difficult to trace any effect.
The RSC, who have over the years invested significantly in supporting chemistry education in schools and colleges through resource development and various other initiatives, commissioned an independent evaluation of a selection of their educational resources from a team based in the UK's Open University.† The evaluation (Murphy et al., 2004) provided evidence that teachers had accessed the ‘Chemical Misconceptions’ materials, were using the activities, and that they were contributing to student learning. The report suggested that engaging with the materials had changed teacher thinking about student learning, and had an on-going effect on teachers' classroom practice, and that the materials were used by experienced teachers in their mentoring of new chemistry teachers. The evaluators commented that the classroom materials reflected a successful embedded pedagogic strategy. It is very helpful (and reassuring) to be provided with evaluation of this kind, yet in my experience it is very unusual for educational researchers to be provided with such clear feedback on the impact of their work. Moreover, this was a project that was primarily about the transfer of research findings into the classroom, drawing on research that had already been undertaken (including, but by no means restricted to, my own research).
I have little doubt that the positive impact of this project reflects the commitment of the RSC as a learned society to invest and engage in supporting school and college teaching in chemistry, and that this provided a relatively rare opportunity to develop research-informed materials that would actually be widely disseminated so that teachers had ready access to them. Much educational research does not benefit from such levels of support in interpretation and dissemination. (The cost of printing books and distributing them to thousands of schools by post is clearly considerable.)
Moreover, despite the positive findings of the evaluation report, I am under no illusions that even such a well-supported initiative can immediately solve longstanding and insidious problems in teaching and learning chemistry. I was reminded of this very recently when I came across a display of the latest batch of chemistry textbooks at a teacher's conference. Flicking through the first book I picked up I came across a figure labelled as ‘ionic bonding’. This was the familiar image of a sodium atom adjacent to a chlorine atom, with an electron being transferred from the sodium atom to the chlorine to atom (of the general form shown in Fig. 1).
The figure was intended to represent ionic bonding, and I suspect most readers will have seen similar figures ‘of’ ionic bonding in school books. Yet this image does not effectively represent ionic bonding. Ionic bonding is about electrostatic forces binding a lattice of ions, not about electron transfer. The diagram shows ion formation, which is clearly something quite different. Certainly it is necessary for ions to exist to have ionic bonding, so ions must be formed for this to happen. But by the same logic, suitable glassware has to be constructed before we can carry out a distillation: but school texts books do not tend to present images of glassblowing labelled as ‘distillation’, and it would seem quite bizarre if they did.
Perhaps textbook authors think that representing ionic bonding in terms of lattice interactions is too complex and abstract for students who are still novices at chemistry, and consider ‘ionic-bonding-as-electron-transfer’ images (such as Fig. 1) as a kind of pedagogic simplification – a teaching model. This might be a potential argument if Fig. 1 can be understood as a useful simplification of ionic bonding (after all, returning to my earlier argument, no one would suggest that the manufacturing of a reflux condenser offers a simplified teaching model of distillation).
Whether the idea of an electron being transferred between atoms is actually inherently any easier to understand than the clumping together of cations and anions is a moot point (as if not, the simplification argument falls down in its own terms). What I am clear about, because my own research demonstrated this, is that advanced students asked to learn about ionic bonding in terms of a lattice of charged ions found that having previously acquired the idea that ionic bonding was electron transfer interfered with the required learning. The teaching model (if we are generous, and for the moment grant it that status) acted as a learning impediment. The electron transfer model supported a ‘molecular’ conception of materials such as common salt – so students tended to think that there were NaCl units (molecules, or molecule like units – pseudo-molecules) within sodium chlorine that were held together by strong ionic bonds (the result of the hypothetical electron transfer) and which were only linked to other NaCl units in the lattice by weak interactions that were not really proper bonds. Such a mental model of NaCl does not explain properties such as a high melting point (as the weak interactions between the pseudo-molecules should be readily disrupted) or conduction when molten (as the pseudo-molecules have no net charge), and leads students to expect the solvated species in solution to be NaCl ‘molecules’.
From this perspective NaCl forms an ionic bond because the sodium atom wants to loose an electron (to leave it with a full electron shell) and the chlorine wants want to gain one (to acquire a full outer shell). Of course, the process shown in Fig. 1 does not even actually allow the chlorine atom to obtain a full outer shell, as that would require a further ten electrons to give Cl11− (a highly charged non-viable species that many students judge more stable than the neutral atom).
I expect this narrative is familiar to most readers, many of whom may have actually been taught in this way, or at least seen school text book accounts that present (or leave readers to infer) this narrative. The only obvious strength of this ‘teaching model’ is that students seem to readily understand, accept and learn the idea that atoms strive for some kind of atomic nirvana through obtaining full shells – so it provide students with a mental model of bonding (and, for example, how and why reactions occur) that allows them to think about chemistry at the submicroscopic scale and feel they understand what is going on.
Against this strength, however, there are some serious weaknesses. The most important being that the account is not true to the science, and becomes a major impediment to learning more advanced models that are based on physical explanations to do with charges and forces. As pointed out above, this alternative conceptual framework (i.e. set of linked conceptions) leads to the wrong predictions of properties in ionic materials. It also leads to misjudgments about the relative stability of many ions and atoms, as those with full outer shells or octets are assumed to be more stable whereas usually a neutral species is actually more stable (in the absence of a stabilising environment such as occurs during solvation). It also leads to nonsensical arguments about why reactions occur: such as students arguing that hydrogen and fluorine react because the atoms want to achieve full shells…in response to a question that gives an equation for the reaction showing the reagents are molecular (so already have ‘full outer shells’).
The scientific model of the process whereby elements are formed in stars (which in effect means the nuclei of different heavier elements are formed, as the temperatures are much too great for neutral atoms to exist) and distributed through supernovae does not have a discrete clean stage when all the material is atomic. The interstellar medium contains atoms, but also molecules and ions. Although there seems to be a psychological preference for beginning chemical narratives with discrete atoms the universe is not minded to organise matter in atomic form before it can react. In reality the elements are formed as plasma and do not all then become discrete neutral atoms on their way to forming compounds.
Certainly – coming back to earth – when we think of how a sample of sodium chloride might be formed in the school laboratory, Fig. 1 has little relevance. A teacher may demonstrate binary synthesis between sodium (a metal, with a metallic lattice, not discrete atoms) and chlorine (a molecular gas, not discrete atoms). More likely students will form sodium chloride by neutralisation and evaporation. They will produce sodium chloride with ionic bonding between a lattice of cations and anions. The reaction does not involve any process that could be reasonably represented by Fig. 1. Sodium ions that are already present in sodium hydroxide, and become solvated in solution, then bind with chloride ions that were (already present and) solvated in the acid solution. No ion formation occurs. No electron transfer is needed. Fig. 1 has no relevance.
Fig. 1 does not even represent an energetically viable process. Whilst the electron affinity of chlorine means that energy is released on the formation of the chloride ion, this is insufficient to match the ionisation energy needed to remove the electron from the sodium atom.
None of this should be news. In terms of my own research with English students, I reported on these problems many years ago. The ways that English college students understood chemical bonding and talked about chemical processes in anthropomorphic terms were the subject of papers in research journals (e.g., Taber and Watts, 1996; Taber, 1998) and the particular issues about understanding ionic bonding were highlighted in periodicals read widely by teachers (Taber, 1994, 1997). Moreover, these particular issues (among others) were highlighted in the RSC project and the classroom resources discussed above: materials that were judged to have been influential on teaching and learning (Murphy et al., 2004). Yet textbook authors continue to re-use representations of the kind shown in Fig. 1, despite these being both bad science, and bad pedagogy. Text books being produced today are still presenting a notion of ionic bonding that has been pointed out to be technically incorrect, internally inconsistent, dependent for causality on the actions of sentient atoms, and that has been found to act as an impediment to the learning of scientifically appropriate models.
These problems are certainly not unique in the English context. Research from Australia had previously identified some of the same issues with students' understanding of ionic bonding (Butts and Smith, 1987), and the general patterns of alternative conceptions identified among English college students have since been found to have resonances with students in a range of other national contexts (Taber, 2013). In the English context, however, textbook authors who perpetuate the ‘electron transfer’ notion of ionic bonding have a powerful ally: the government's Department of Education. A previous government initiative to strengthen teaching had recommended the RSC materials on Chemical Misconceptions to schools (Key Stage 3 National Strategy, 2003), but despite this, the government ministry recently published a new draft curriculum document (Department for Education, 2014) that sets out as canonical knowledge for 16 year old students in England that: “atoms bond either by transferring electrons from one atom to another or by sharing electrons” (p. 11).
As long as governments set out such dubious statements as target knowledge for learners it is hardly surprising that textbook authors will choose to maintain flawed teaching models rather than look to offer a scientifically acceptable model of the chemistry. Clearly in this case the impact of widely disseminated research has not been sufficient to influence the government ministry which decides what students should be taught.
The problem with looking for research impact, is that it is unreasonable to expect most individual studies to directly bring about widespread changes in practice that can be traced back to that particular research (see Fig. 2). For one thing, most research studies are parts of more extensive research programmes where understanding, and recommendations for practice, develop iteratively over time. Each discrete study adds a little to understanding within the research community. In addition, practitioners often borrow or copy good ideas from each other (deliberately or sometimes without even realising) and even if the teacher whose practice is taken as a model knows what research has influenced that practice, this information is seldom made explicit as good practice is spread among a community of practice. In any case, often practitioners do not know the details of the research that informs their own practice. Some teachers read research journals such as CERP, but this is not the norm at school levels – and many teachers at university level who are not themselves active in pedagogic inquiry are too busy keeping up with their own research fields to regularly read reports of educational research.
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Fig. 2 The influence of research on educational practice is seldom in the form of clearly identifiable direct impact. |
Research results and recommendations may be reported in other publications such as practitioner journals or even sometimes mainstream media – but the link to the original research papers may not always be explicit. (Often practitioner journals look for articles that cite short bibliographies of accessible further reading, rather than academic citations of the kind expected in research journals.) Teaching associations or networks, and learned societies and professional bodies, may sometimes produce digests of research findings or research-based initiatives. Research will often be read by those responsible for teacher education and professional development – but their priority is often to translate bodies of research into core recommendations for practice that teachers (especially those setting out as new teachers) can readily engage with.
Of course these various potential intermediaries between research reports and practitioner knowledge interact in complex ways. Any particular research study will have been read by a finite number of people, whose thinking will have been influenced in different ways and to different extents, and any resulting shifts in thinking may influence their own work (in their own research, preparing teachers, in informing educational policies of learned societies etc.) in different ways and to different degrees – and they then engage in relevant discourse with others undertaking similar or different work (e.g. the textbook author who reads a policy document from a teaching association written by an association officer or consultant informed by various research). Any particular teacher will be informed by any reading of research, plus any reading of secondary literature, their own pedagogic preparation (which may be quite limited if they are teaching in higher education contexts), the practice of those about them, and so forth. There is a complex network of individuals in different roles each influenced by and influencing many others. Much of the time most of those individuals are only very vaguely aware of most of the research studies that have influenced the ideas, language and practice that is part of the milieu in which they work.
Something similar is true about the impact of education research. The process is convoluted and diffuse, and very difficult to track, and indeed sometimes there is a considerable delay before research impacts on practice (although, thankfully, not quite as long as it takes radiation to emerge from the sun). Despite this, teaching chemistry is improving as a result of chemistry education research. The occasional disappointments and reversals remind us just how complex the process is, and why researchers have a responsibility to do what they can to help disseminate and reconceptualise research in ways that can influence teaching.
Footnote |
† The evaluation sampled a selection of RSC resources. As well as the Chemical Misconceptions volumes, the evaluators also considered other hard copy materials (Classic Chemistry Experiments; Classic Chemistry Demonstrations; Ideas and Evidence), multimedia materials on CDROM (Alchemy?), professional development materials (Improving Teaching and Learning Chemistry using ICT; Using Assessment to Improve Learning in Chemistry and Science) and web-based materials (Joint Earth Science Education Initiative). The full evaluation report is available at www.rsc.org/images/2004evaluation_tcm18-12552.pdf. |
This journal is © The Royal Society of Chemistry 2014 |