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Challenging Chemical Misconceptions in the Classroom? The Royal Society of Chemistry Teacher Fellowship project 2000-1 Keith S. Taber Homerton College, University of Cambridge & Royal Society of Chemistry presented to the symposium Key Notes in Chemistry Education at the British Educational Research Association Annual Conference, Cardiff Univesity, September 7-10 2000 Taber, K. S. Challenging chemical misconceptions in the classroom? 2000 © Keith S. Taber presented to the symposium Key Notes in Chemistry Education at the British Educational Research Association Annual Conference 2000, University of Cardiff Dr. Keith Taber Senior Lecturer in Science Education Homerton College, University of Cambridge Royal Society of Chemistry Teacher Fellow 2000-2001 c/o Education Dept. Royal Society of Chemistry Burlington House Piccadilly London W1V 0BN e-mail: [email protected] 2 Challenging chemical misconceptions in the classroom? Abstract It is now well established that most learners in schools and colleges have alternative conceptions (or ‘misconceptions’) about aspects of the science curriculum. Indeed such alternative conceptions have been found in (virtually?) all topics at all grade levels where researchers have thought to look for them. Teachers are now trained to review the likely misconceptions associated with a topic as part of their lesson preparation. Yet while there is a great deal of information available about the range and ingenuity of pupils’ alternative ideas, there is less practical help for teachers in dealing with them. The assumption is that by being aware of common misconceptions the teacher will plan teaching that challenges and overcomes them. Yet research suggests that many ideas are idiosyncratic, and that some alternative conceptions are extremely stable despite explicit challenges in the classroom. Published projects that have developed ‘constructivist’ teaching approaches have had resource support far beyond that available to most practitioners. Research into learners’ ideas has been (at least in part) moving beyond the ‘stamp collecting’ stage of simply observing and recording the enormous range of misconceptions out there, to more theoretically ground studies which try to explore the ‘hows’ and ‘whys’ of conceptual development. In time this research may prove to be of great value to classroom teachers. In the meantime teachers can be supported by being provided with materials that are designed to help them elicit and challenge common misconceptions. The Royal Society of Chemistry (RSC) is funding a Teacher Fellowship to develop such materials for key science concepts relating to the learning of chemistry at secondary/sixth form level. It is intended to provide materials that enable classroom teachers to identify and challenge common ‘misconceptions’ in their pupils. The RSC will publish and distribute the resources free at the end of the project. Key words: constructivism, learning chemistry, challenging misconceptions, free resources. 3 Taber, K. S. Challenging Chemical Misconceptions in the Classroom?: The Royal Society of Chemistry Teacher Fellowship project 2000-1 1. Introduction: alternative conceptions and constructvism. 2. Practitioners’ responses to alternative conceptions. 3. Beyond ‘stamp collecting’. 4. The RSC teacher fellowship project (1): How can the RSC help classroom teachers? 5. The RSC teacher fellowship project (2): How can teachers help the RSC project? 6. Hors d’oeuvre: some examples of pupil responses. 7. Conclusion: the future of alternative conceptions research? 1. Introduction: alternative conceptions and constructvism. Children often have ideas about aspects of ‘the way the world works’ which are at variance with the scientific models. This is explained through the ‘constructivist’ notion that humans build up their own models of the world based on their experiences.1 Even young children behave like scientists in developing models to represent their world. 2 However, they are often rather poor scientists who have not studied Popper’s ideas about the importance of ‘falsification’!3 Once these naive conceptual structures start to develop they become the frameworks through which the world is understood. As language is often poetic and imprecise, and children’s early informers are often not well versed in cutting edge science, there is plenty of scope for alternative ideas to become extensive and well established. Pupils (and students) will bring these alternative ideas to their science lessons. As they do not realise their ideas are at odds with accepted science, they will expect the teacher’s words to make sense in terms of their existing notions. More often than not, ‘sense’ can be made of science lessons in terms of alternative conceptions. Sadly, it is often not the sense intended by the teacher! 4 4 Challenging chemical misconceptions in the classroom? If the teacher is not aware of the pupils’ ideas, then their responses in class may be judged to be ‘confused’ or ‘non-sensical’, and to represent inattention or lack of understanding, or considered to be ‘poorly expressed’ due to limited linguistic ability. Of course, there may often be inattention, and even with attention there often may be misunderstanding, but this is not the same as having no understanding: the pupil may be understanding differently. Understanding differently is still ‘wrong’ from a curriculum viewpoint, but it is a different pedagogic problem to not understanding! Of course pupils may often lack linguistic skills, and express their ideas poorly, but sometimes they are expressing their ideas well, those ideas just match the teacher’s ideas poorly. Again, this is a problem for the teacher, but, again, it is a different problem. So constructivism tells teachers that they did indeed have a problem teaching scientific ideas (as well they knew) but that often it may not be the problem they thought it was! This is very important. If a pupil does not understand an idea because it does not make sense, then certain remedial action is appropriate. If the material makes perfect sense to the pupil in terms of a different, alternative, understanding, then a different course of action is needed. If a pupil can not clearly explain her ideas (so as to produce a satisfactory examination response) a certain type of help is needed; but if the pupil is explaining alternative ideas clearly, but they seem confused because the teacher is thinking along different lines, then a different sort of help is needed. It is important then that teachers recognise when pupils are ‘understanding differently’ and know how to respond to this, just as they need to recognise and know how to respond to limited comprehension or lack of expression. 2. Practitioners’ responses to alternative conceptions. As a general rule humans have a natural drive to make sense of the world. Most pupils who do not understand a lesson would want to, and if the teacher works with them can be made to ‘learn the lesson’. Perhaps the teacher just needs to go through the steps more slowly, or go over the meaning of some of the vocabulary. Perhaps the teacher needs to introduce some sort of analogy or metaphor that will help the pupil understand. However, when a pupil holds an alternative conception, the natural motivation to understand does not operate - because the pupils already think they understand the topic: it makes sense to them. 5 Taber, K. S. So - once the teacher is aware that an alternative conceptions is operating - it is necessary to make the pupils aware that they have not understood the scientific idea. Before the teacher can try and make the material make (the intended) sense for the pupil, they have to persuade them that their current ideas do not make sense. In other words, the alternative conceptions have to be challenged. This is necessary because there is a vast amount of research that shows that ignoring the alternative conceptions, and just trying to teach over them, seldom works. Occasionally a pupil might simply take up the teacher’s new way of looking at things: more often the pupil assimilates the new examples and terms into their existing version, or produces some sort of amalgam of the two, or learns the new material by rote, only to revert to their existing ideas over the subsequent weeks or months. The research that has looked at using these ideas in teaching (rather than just collecting examples of kooky science) shows that teachers need to start by making explicit pupils’ existing understanding, and then work from there. 5 The national curriculum for Initial Teacher Training actually require student teachers to show they do this. 6 However, it requires a superbly confident teacher, with plenty of time for critical reflection - let alone lesson preparation - to do much more than pay lip service to these ideas. After all, if you start a new topic on Monday afternoon, and the next lesson is Wednesday morning, it is cutting things rather fine to leave prep. for Wednesday till after you have analysed the pupils’ work from the elicitation lesson on Monday. Especially when there are half a dozen other classes to worry about in between! This is not in any sense to undermine the constuctivist approach, but to recognise the inherent difficulties. The more experience a teacher develops, the greater their reservoir of examples, tricks, demonstrations, metaphors, images etc., the easier it is to see teaching as a real-time interactive process: but the realities of school life (and the expectations of Ofsted etc.) require teachers to largely work from pre-planned work schemes. And our technicians are usually grateful for this! There are published examples of constructivist teaching schemes in action, from Ros Driver’s CLISP project for example. 7 These seem to be successful, without relying on superhuman efforts. However, they do represent curriculum development projects where time, thought and access to peers and expert consultants were made available. Presumably each of the teachers involved in those reported projects were simultaneously teaching other topics to their other classes - and it is likely they were only able to apply the constructivist approach to a much more limited extent in these more ‘normal’ teaching contexts. 6 Challenging chemical misconceptions in the classroom? 3. Beyond ‘stamp collecting’. Much of the research into alternative conceptions in science has been characterised as ‘stamp collecting’ or ‘butterfly collecting’. Researchers have been a bit like Darwin and Wallace at the stage where they are still amassing their collections and thinking ‘that’s an interesting specimen’, without any meaningful theorising. A lot of these new Darwins have presented their specimens to the appropriate museums (i.e. science education journals) and left it for others to devise an ‘Origin of Conceptions’. I suspect there are also a great many Wallaces out there as well, who have found that many of their most interesting specimens have ended up shipwrecked at the bottom of the seas of masters’ dissertations and oceans of doctoral theses, with little hope of ever being brought back to the surface. It is some years since it was pointed out that if research into children’s ideas was going to be of maximum use to teachers something more was required than catalogues of conceptions elicited from random individuals or groups of learners. To take us forward studies need to be sufficiently detailed to tell us not just about the conceptions themselves, but about conceptual change. We need to know why certain types of conceptions are acquired, and how to challenge them effectively, how to usefully build on the ideas children bring to lessons, and how to avoid our teaching being misinterpreted and commonly leading to ‘misconceptions’. In my view we need to look at individual pupils’ thinking in much more detail to study how ideas change over time, and how different concept areas are related in the pupils’ minds. Of course some of this work exists, and there are some useful theoretical contributions, but we are far from having an understanding that enables research to effectively inform the planning and execution of science teaching at any level of detail. By this I mean that we are unable to turn to an area of the curriculum and make useful predictions (ab initio) about the types of alternative conceptions that we will find, and how best to deal with them. Perhaps this is an unrealistic aspiration, but the lack of such a ‘science’ of science teaching is why teaching according to constructivist principles is so difficult in practice. 7 Taber, K. S. 4. The RSC teacher fellowship project (1): How can the RSC help classroom teachers? Of course, there are sources which give advice about how to approach certain science topics, and some of this is based on good research into learners’ ideas and how to develop them. Yet, to a large extent, the best that is on offer to teachers for most topics - certainly without undertaking a search in a research orientated library - are secondary sources which summarise some of the literature on common misconceptions that are likely to be found in most classes. 8 This is very useful as it alerts the teacher to key ‘barriers’ to the intended learning, and both makes it more likely that the teacher will spot when pupils are applying these ideas, and that the teacher will stop to check pupils’ understandings of the material at the most appropriate points. However, if the teacher wishes to go beyond this and try and elicit alternative conceptions and actively challenge them, considerable work may be involved. Many teachers who have committed to this approach find it worthwhile, and there are straightforward general techniques that may be used to explore pupils’ ideas (such as concept mapping). Yet if most teachers are to pay more than lip-service to becoming ‘constructivists’ in their classroom practice, they will need more support - at least to get them started. A project being funded by the Royal Society of Chemistry (RSC) is hoping to provide some of that support. Each year the RSC funds a Teacher Fellow to work on some aspect of supporting the teaching of chemistry/science. During the current academic year I will be seconded to the RSC as Teacher Fellow to develop materials to support classroom teachers (at secondary and sixth form level) challenge common misconceptions. The intention is to provide materials that will be sent (free of charge) by the RSC to UK schools and colleges. These materials will hopefully include a variety of exercises for use in the classroom, as well as supporting information. The exercises will be designed to help teachers find out if their own pupils hold some of the alternative conceptions reported in the literature. The supporting materials will explain the ‘misconceptions’, and their significance, and provide support in challenging them . It is expected that many of the exercises may act as suitable starting points for classroom discussion that can compare the scientific models with the alternative views suggested by pupils. Although there will not be the time to produce complete teaching schemes (and the intention is to provide exercises that will slot into existing teaching programmes), it is hoped that materials will be provided that will address some of the key concepts in chemistry, and basic science, where research suggests alternative ideas that block intended learning are commonly encountered. 8 Challenging chemical misconceptions in the classroom? 5. The RSC teacher fellowship project (2): How can teachers help the RSC project? Although it is possible for an experienced teacher to spend some time reading research papers in a University library and then write exercises that are meant to elicit alternative conceptions and make learners question their thinking about key chemical ideas; this is no guarantee that the materials will be effective in the classroom. It is hoped that the materials to be published and distributed by the RSC will have been tried out with real pupils and students in a variety of ‘normal’ classes. Teachers of science/chemistry are invited to try out sample exercises with their classes, and to read through, and comment on, drafts of the supporting documentation. Trials of materials will enable drafts to be tweaked to ensure they are suitable for the intended readership, and will provide samples of pupils’/students’ comments that can be used as examples in the final publication. A large number of teachers have already expressed an interest in helping with the project, but clearly it is only possible to usefully try out exercises for topics with classes at an appropriate stage of their course, and the work is to be completed in one year, so any more volunteers are welcome! It is hoped that the authentic involvement of a range of teachers and their pupils’ in a variety of schools and colleges will ensure that the final product is something that will be widely used in schools, and not just gather dust on a prep. room shelf. 6. Hors d’oeuvre: some examples of pupil responses. The project only started officially on the 1st September, so it is too early to provide much detail of the materials that will be developed. However, it is possible to give you some tasters from some probes I have already drafted based on my previous research, based on a study of A level students’ understanding of chemical bonding. 9 Taber, K. S. Consider the three chemical species shown in figure 1: A: Na + 11 + figure A: the sodium one plus ion C: Na B: Na 11 + figure B: the sodium atom 11 7- + figure C: the sodium seven minus ion Figure 1: three chemical species Which of these species is more stable? This is a somewhat ambiguous question. If we are talking about which is hardest to ionise, then I guess we would all agree it is the cation. If, instead, we consider which is least likely to either pick-up or shed an electron, then I think we would decide the atom: after all it is neutral so it will not strongly attract any other species. Clearly the question is open to interpretation, as we think about possible contexts in which we might be answering the question. Previous research suggests that students strongly associate stability with ‘octets’ or full outer shells. Most chemists do, but probably not to the extent of many A level students. The diagrams were used as the basis of a ‘chemical stability probe’. The probe compares each pair of diagrams, and offers four options. For example: • A is more stable than B • A and B are equally stable. • A is less stable than B • I do not know which statement is correct. Respondents are asked to select a response and give their reasons. The probe has been tried by a number of groups now. For example, thirteen A level students at a sixth form College have had a look at this. 11/13 thought that the cation was more stable than the atom. One respondent thought the opposite, and one did not know. 10 Challenging chemical misconceptions in the classroom? I think that in the absence of any given chemical context the best response would be that the neutral atom would be the most stable. We might argue about this, but more interestingly 10/13 of these A level students who had all studied basic A level chemistry topics thought that the neutral atom was less stable than the sodium anion! This is not a freak result, as I have had similar responses from other institutions. So clever young people taking our ‘gold standard’ qualification believe that a the sodium seven-minus anion - something they have never come across in their studies - having a large excess of charge, and something that is an anion of a strong metal, is a stable species! Why? Well a typical reason given is that “C [the anion] has a full outer shell of electrons”. (Of course, this is not true anyway, as a full outer shell for sodium would require 18 electrons, not 8!) When I started teaching chemistry I would never have expected this. Indeed even when I was undertaking research which kept turning up references to octets / full shells as the key explanatory principle in chemistry, I still would not have expected this. 9 Only when I found that over four-fifths of respondents agreed with a statement in another exercise that “the [sodium] atom would become stable if it either lost one electron or gained seven electrons” did I devise the probe I am referring to here. 10 Now if I was teaching A level chemistry now, I would find it very useful to be aware that most of my students thought that octets of electrons provided so much stability that metal atoms would readily form highly charged anions to obtain octets. I would be most unlikely to spot this - it seems so crazy - by chance. Yet now that the research has been done it is possible to provide teachers with a simple one page exercise which diagnoses whether students think this, and provides a background for a class discussion of the issues. This is the type of material that the RSC project can provide, which saves the teacher either having to spend considerable time repeating the original research, or reading the research journals, and then having to think about how to go about checking the students’ ideas to see if they are thinking that way. I will give you another related example: Figure 2 gives a more explicit representation of the processes by which a sodium atom may become an ion and vice versa. It sets the process outside of a chemical context, and by showing the electron provides a slightly less ambiguous task. 11 Taber, K. S. electron ? 11 + 11 + ? sodium ion sodium atom Figure 2: atom, ion & electron This probe was intended to relate the notion of ‘stability’ - as considered above - to that of ‘reactivity’, which may (or may not) be seen as antonyms. However, here I would just like to consider the notion of which process is seen as likely to occur. The format is similar to the previous probe, with a multiple choice section of four options (including a ‘I do not know’ option), and space for an explanation. For one part of the exercise the four options were: • The sodium atom will emit an electron to become an ion. • The sodium ion and electron will combine to become an atom. • Neither of the changes suggested above will occur. • I do not know which statement is correct. This exercise has been undertaken by over fifty Y10 pupils in one school. Of 54 pupils answering that item, 3 did not know what would happen, 7 thought neither process would occur, and 1 thought the atom and electron would combine. 43, that is four-fifths, thought that the atom would emit an electron. Why? There we a range of suggestions, but many were variations on the theme of: “To be stable the sodium atom needs to get rid of an electron to make it stable. It then becomes Na1+” 12 Challenging chemical misconceptions in the classroom? Of course we talk about the stability of the sodium cation, but many pupils take this to mean that a neutral atom will spontaneously emit an electron, whereas a positive ion can not attract an electron if it means losing a full shell. Basic electrostatics is seldom taken into account. Overall: 2% correct, 93% wrong. As a teacher, I would find it useful to be aware that my pupils are thinking that way. One fair criticism of the questions discussed above is that chemistry usually deals with real chemical contexts rather than abstract ‘what if’ questions about isolated atoms and electrons. However, the rationales used in the simplified situations discussed are carried over into more ‘chemically relevant’ examples. Consider another probe. This commences with some information about a reaction: Hydrogen reacts with fluorine to give hydrogen fluoride. The equation for this reaction is: H2(g) + F2(g) 2HF(g) The word equation is: hydrogen + fluorine hydrogen fluoride Then a diagram is presented: +1 hydrogen atom +1 +1 +9 hydrogen molecule fluorine atom fluorine molecule +9 hydrogen fluoride molecule +9 +9 +1 13 Taber, K. S. Figure 3: why do H2 and F2 react? The respondents are then asked: “In your own words, explain why you think hydrogen reacts with fluorine:” This was undertaken by 29 A level students in a school sixth form. Here is an example of the explanation given by one student: “Fluorine is a halogen and has 7 outer electrons. To be stable it would like 8 electrons in its outer shell. By covalently bonding with the hydrogen atom which would like 2 electrons in its outer shell they form hydrogen fluoride which is stable” Yet, the reaction equation given clearly refers to H2 and Cl2. The figure shows the molecules of chlorine and hydrogen where chlorine already has “8 electrons in its outer shell” and hydrogen already has “2 electrons in its outer shell”. If explaining chemical reactions is important in chemistry then this student does not seem to have a very sensible explanation. In that particular group of students there were 24 explanations much like this - four fifths of the group think they know why this reaction will occur, but their explanations are contradicted by the information given in the question! Again, as a classroom teacher, this reveals a significant source of misunderstanding among most of the students, that may not have been obvious to the teacher without using the exercise. 7. Conclusion: the future of alternative conceptions research? Research into learners’ ideas in science has been a major activity for several decades. If it is to continue to be a ‘progressive’ research programme it needs to go well beyond the collection and cataloguing of quaint misconceptions. We need research that can be used in teacher training to inform teachers of the ‘hows’ and ‘whys’ of conceptual development, so that practising teachers have an integrated framework for understanding learning and curriculum that enables them to plan and teach as contructivists. It is one thing to accept the premise that learners have to re-construct knowledge rather than just absorb it: it is another to know how to teach accordingly within the resource constraints in real classrooms. 14 Challenging chemical misconceptions in the classroom? At the moment we do not have this theoretical structure, and true constructivist teaching requires a level of research activity within the classroom that teachers do not have the time for (even assuming they have the training, the confidence, and the inclination). By its nature, constructivist teaching requires close attention to individual learners, and it may transpire that pupils and students are so different that teachers will always have to spend a lot of time diagnosing the idiosyncrasies of each learner if they want to teach effectively. Yet, it is also possible that there may be enough commonality in most classes to be able to help teachers make short-cuts. We just do not yet know enough. We know some alternative conceptions are very common, and some seem most rare. Some may be easily overcome, and others seem extremely resilient. Theory tells us that some are best seen as staging posts or stepping stones to scientific knowledge, rather than as obstacles. Some may be best seem as acceptable adjuncts to scientific knowledge, or alternative narratives, rather than as unacceptable competitors. Perhaps a few are best dealt with by ignoring them, in the hope that they will wither, whilst many others need a head-on assault. There are too many uncertainties for us to expect all classroom teachers to fully adopt the constructivist approach. Hopefully, in time, the research programme will start to provide a more ordered understanding of learners’ ideas in science. In the meantime, perhaps projects such as this RSC sponsored project will at least provide some helpful exemplars of useful exercises, and some short-cuts to diagnosing and challenging common alternative conceptions, so that teachers are not expected to start from scratch will all their classes. References. 1 Pope, Maureen, & Gilbert, John (1983) Personal experience and the construction of knowledge in science, Science Education, 67 (2), pp.193-203. 2 Driver, Rosalind (1983) The Pupil as Scientist?, Milton Keynes: Open University Press. 3 Wolpert, L. (1992) The Unnatural Nature of Science, London: Faber & Faber. 4 Taber, K. S. (1999) Alternative conceptual frameworks in chemistry, Education in Chemistry, 36 (5) pp.135-137. 5 Driver, Rosalind & Oldham, Valerie (1986) A constructivist approach to curriculum development in science, Studies in Science Education, 13, pp.105-122. 6 DfEE 1998 Circular 4/98: Standards for the award of qualified teacher status: Annex A Department for Education and Employment. 7 e.g. Wightman, Thelma, in collaboration with Peter Green and Phil Scott (1986) The Construction of Meaning and Conceptual Change in Classroom Settings: Case Studies on the Particulate Nature of Matter, Leeds: Centre for Studies in Science and Mathematics Education - Children’s learning in science project, February 1986. 8 Driver, Rosalind, Ann Squires, Peter Rushworth and Valerie Wood-Robinson (1994) Making Sense of Secondary Science: research into children’s ideas, London: Routledge, 1994. 9 Taber, Keith S. (1998) An alternative conceptual framework from chemistry education, International Journal of Science Education, 20 (5), pp.597-608. 15 Taber, K. S. 10 Taber, K. S. (1999) The truth about ionisation energy: an instrument to diagnose common alternative conceptions, School Science Review, 81 (295), pp.97-104. 16