question-asking on unfamiliar chemical phenomena: differences between students, preservice teachers...

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parte 2 de: Las preguntas de los estudiantes ante dispositivos experimentales.

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  • 1. 290 Successful Chemistry Education Norman REIDUniversity of Glasgow, Scotland;Eldon Street, Glasgow, G3 6NHEmail: dr_n@btinternet.comAbstractPublished research has indicated several key ways by which we can make chemistry education successfuland exciting for all levels of learners. The curriculum aims have been described and the reasons forlearner difficulties have been identified and some ways forward tested and found to be highly effective inmaking chemistry more accessible. The reasons that encourage positive attitudes are known and the waysto encourage positive attitudes demonstrated.This paper will summarise a few of the key findings and these will point forward to ways to improvechemistry education, especially at school level. Past research also defines the agenda for future enquiry.It is important that the curriculum for school chemistry meets the needs and aspirations of the majority oflearners. To reduce difficulties, the evidence shows clearly that the key lies in appreciating the controllinginfluence of limited working memory capacity. Research is described where very large improvements inperformance can be achieved simply be re-casting the written materials used by the learners in order theminimize mental overload.The key to positive attitudes lies in curriculum design, quality teaching and making the learners aware ofthe importance of chemistry as basis for exiting careers. Activity outside the school have almost no effectin encouraging young people to continue their studies in chemistry.The argument here is that there is sufficient clear, confirmed evidence from quality research to indicatehow to move chemistry education forward so that more learners can be released to find chemistry anexciting and fulfilling subject, a goal we all share.IntroductionIt is sad that, in chemistry education, we so often do not respect the research in the field and are happy tomove forward on the basis of opinion, assertions, speculations. Indeed, chemistry education, like otherareas of education, is full of bandwagons, based on little more than opinion, which are used to plan anddevelop curricula and teaching. History is littered with the failures arising from these developments.In order to move chemistry education forward, it is essential to base all our developments on clearevidence from research but research is very variable in usefulness (table 1).Table 1 - Types of researchTypes of Research in Chemistry Education Looks back at some development and Descriptive research has its place but is very 1 Post hoc comments sagelylimited Develop a new way to teach, gaining evidence It is always better for the development changes 2 Brainchild to show it is better the advocates - very limited value Develop a new way based on past evidence This is part of how the sciences always work. 3 Innovative and explore its effectivenessNew research builds on past evidence Ask why things work as they do and look forThis is the key: if we know why, we can 4 Fundamental fundamental principles predict and then test the predictionsSadly, educational research is full with examples of the first two and, as a result, we do not move forwardcoherently and usefully. This paper seeks to summarise some of the key findings from research incategories 3 and 4. It derives from reviews already published [1-3].CnS La Chimica nella Scuola XXXIV - 3 PROCEEDINGS ICCE-ECRICEAugust 2012

2. 291Some Key QuestionsChemistry education has faced a small number of critical issues in recent decades:(a) Knowledge in chemistry is expanding exponentially. At the same time, chemistry is under threatin terms of status and time allocations, especially at school levels. Can we justify its place in thecurriculum?(b) Why is chemistry often seen as difficult by learners and what can we do to reduce theproblems?(c) In many (but not all) countries, chemistry is unpopular at senior school and university levels.What causes this and what can we do to improve the situation?(a) Why study chemistryThe proportion of the intake in a typical secondary school that will ever study chemistry at university in aserious way is, perhaps, as low as 2% but certainly not more than 5%. Designing the school curriculum tolead to university chemistry means we are failing the needs of the vast majority. Here are some betteraims (figure 1): Figure 1 - The Role of School ChemistryHarvey and Green looked at what employers wished from the graduates they employed (in alldisciplines). Knowledge and skills had their place but the employers really wanted some graduates whohad the skills and abilities to transform the organization, with more emphasis on specific skills like team-working, report writing, making oral presentations [4].In another study, chemistry graduates were approached two years after completing their first degree to seehow they thought their undergraduate experiences had prepared them for work. The graduates werepositive but they also wanted more emphasis on the generic skills the employers had identified [5].We need to look at the world into which our students move and ask if their experiences in chemistry arepreparing them well. This is a key future research area.(b) What Makes Chemistry Difficult?The work started in the late 1960s after the introduction of new curricula in schools in many countries.The areas of difficulty were quickly identified and researchers started to explore the nature of theproblems and how they might be resolved.In the 1950s, a study in psychology led to the paper with the amazing title: The magical number 7 2.Published in a prestigious psychology journal, this quickly became one of the most quoted papers of alltime. Miller had developed reliable ways to measure the capacity of what he called short-term memory[6]. In a moment of inspiration, Johnstone and Kellett [7]connected the findings of Miller to work on dif-CnS La Chimica nella Scuola XXXIV - 3 PROCEEDINGS ICCE-ECRICEAugust 2012 3. 292ficulties in understanding chemistry. In simple terms, they hypothesized that difficulties in understandingarose when the human brain was asked to handle too many ideas at the same time.In a rigorous experiment, this hypothesis was tested by Johnstone and Elbanna [8,9]. They found that thecapacity of what is now known as working memory was, indeed, the key factor determining success inmuch chemistry. Later, it was shown that this applied to all subject areas but the problems are most acutein highly conceptual areas [10]. To grasp a concept, the learner almost inevitably has to hold many ideassimultaneously. This may well overload the working memory and cause understanding to be more or lessimpossible.The controlling effect of limited working memory capacity is considerable. The average adult can hold 7ideas (Miller called them chunks) at the same time. Learners with small working memory capacities canoften perform much less well (typically between 15% and 25%) in examination papers. The problem isthat the capacity of working memory is determined genetically and cannot be expanded. It is simply afunction of the way the brain is wired up and does not, of itself, determine ability.Here is an extreme example of the kind of question which almost inevitably will overload the workingmemory: If 20 ml of 0.02M potassium permanganate is acidified and treated with excess potassiumiodide solution, iodine is released. When this iodine is titrated against 0.1M sodium thiosulfate solution,using starch indicator, what volume of thiosulfate would be used ? However, there is a way to solve thiswithout overloading the working memory [3].The working memory is where we think, understand and solve problems. Much of the rest of the brain issimply a store for holding information, understandings, opinions, experiences and so on. In learning, ifthe capacity of the working memory is exceeded, understanding is more or less impossible.The critical importance of working memory is stressed in a review by Kirschner et al. [11]. The paper isentitled: Why minimal guidance during instruction does not work: An analysis of the failure ofconstructivist, discovery, problem-based, experiential, and inquiry-based learning. They talk ofFAILURE. They then list a whole number of fashionable approaches which can be seen commonly inmuch chemistry education today. The point they are making is this: NONE of these ways holds the key insolving the difficulty issue and they note:Any instructional theory that ignores the limits of working memory when dealing with novelinformation or ignores the disappearance of these limits when dealing with familiar information inunlikely to be effective. (p. 77).Constructivism has as its central tenet that learners construct their own understandings and that these maynot be the same as the understandings provide by the teacher. The evidence for this is overwhelming.However, suggesting that we can teach constructivistically is simply a nonsense. All learners, all the time,are constructing their understandings. It does not matter what we do. Teaching constructivistically ismeaningless in that constructing understanding takes place inside the head of each learner, inaccessible tothe teacher.Constructivism is an excellent description of what goes on naturally. It has little predictive value andcannot direct us to better teaching, simply because what happens overtly in the classroom has no directbearing on a process which takes place naturally inside the head of each learner.Kirschner et al. speak of discovery, problem-based, experiential, and inquiry-based learning.[11]. Allthese are what might be seen as trendy bandwagons that have gained certain currency among certaineducators. While all four possess positive features, none of them holds the answer. If they areimplemented within the limitations of working memory capacity in mind, they may bring better learning.If they generate increased cognitive loads, then learning will deteriorate. It is nothing specifically

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