Designing and evaluating short teaching interventions about the epistemology of science in high...

Designing and Evaluating ShortTeaching Interventions About theEpistemology of Science in HighSchool Classrooms

JOHN LEACHCentre for Studies in Science and Mathematics Education, The School of Education,The University of Leeds, Leeds, United Kingdom; Gothenburg University, Sweden

ANDY HIND, JIM RYDERCentre for Studies in Science and Mathematics Education, The School of Education,The University of Leeds, Leeds, United Kingdom

Received 26 March 2002; revised 1 July 2002; accepted 9 August 2002

ABSTRACT: This paper reports the design and evaluation of small-scale teaching inter-ventions addressing the epistemology of science as part of the regular high school sciencecourses followed by English students. Although there is a growing consensus that the cur-riculum should include aspects of the nature of science, there is a limited body of knowledgeabout how this might be achieved in an already crowded curriculum. Single lessons weredesigned in order to raise epistemological questions in subject matter contexts likely tobe encountered by students as part of regular teaching. This paper presents findings froman evaluation of the teaching, addressing both the impact of the resources and associatedteaching strategies on student learning, and teachers’ reactions to the interventions. Theteaching interventions were successful in their aim of “opening up” epistemological issueswith a majority of students. A significant minority of students did not make any progress interms of their responses to diagnostic questions, even though they appeared able to partici-pate in the lesson’s activities. The paper concludes with a discussion of issues surroundingthe design and implementation of teaching with an epistemological focus in the context ofcrowded science curricula. C© 2003 Wiley Periodicals, Inc. Sci Ed 87:831–848, 2003; Publishedonline in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/sce.10072

RESEARCH FOCUS

There is a growing consensus that science curricula should promote an understanding ofthe nature of science amongst students (e.g., AAAS, 1990; Millar, 1996; Millar & Osborne,1998; National Research Council (NRC), 1996). There is also considerable evidence that,in some settings, many high school science students give limited and inaccurate portrayalsof the nature of scientific knowledge (e.g. Brickhouse et al., 2000; Desautels & Larochelle,1998; Driver et al., 1996; Leach et al., 2000; Lederman & O’Malley, 1990). In particular,

Correspondence to: Prof. John Leach; e-mail: [email protected] grant sponsor: Nuffield Foundation.

C© 2003 Wiley Periodicals, Inc.

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students often appear to view theoretical explanations as emerging unproblematically fromdata, through inductive processes. Few students appear to recognize that there is an onto-logical difference between things that can be seen and measured (data) and the entities thatare often used to explain those data.

Although there are some curriculum resources available that support teaching aboutthe interactions between science, technology, and society, fewer materials are availablewhich address epistemological issues about the nature and status of scientific knowledge.Furthermore, there is considerable evidence highlighting the barriers faced by teachers indeveloping teaching episodes that address the nature and status of scientific knowledge(e.g. Abd-El-Khalik, Bell, & Lederman, 1997; Smith & Scharmann, 1998). These barriersare particularly acute when science teachers feel that the amount of conceptual content tobe covered in a curriculum leaves little space for developing ideas about the nature andstatus of scientific knowledge. In recognition of the pragmatic difficulties of introducingepistemological ideas about science into a crowded curriculum, we developed six shortteaching interventions (approximately one lesson each) with the aim of raising epistemo-logical questions in contexts likely to be encountered by high-school students during theirregular science courses. Three lessons focused upon the relationship of models and data.This paper reports our evaluation of two of these three lessons, in terms of student learningand teachers’ perspectives on the practicalities of introducing epistemological questionsthrough short interventions such as these. Sufficient evaluation data were not available forthe third lesson. The types of models and data at stake are different in each of the two lessons.

TEACHING ACTIVITIES TO ADDRESS THE NATUREOF SCIENTIFIC THEORIES

The teaching activities reported in this paper were developed, in association with agroup of teachers, to address the status of scientific theories with high-school students(aged 16–18). The activities draw upon episodes in the history of science, which are relatedto the science curricula followed by English students. We worked with a group of nineteachers who responded to an advertisment in a professional magazine, asking for collabo-rators interested in working with us on curriculum development with a focus on ideas aboutscience in the science curriculum studied by students between the ages of 16 and 18. Thegroup of teachers included three women and six men. Amongst the nine teachers, there werethree physicists, three chemists, and three biologists. The teachers were at very differentstages in their careers, ranging from those in the first 5 years of teaching to senior teacherswith management responsibility in their school’s science departments.

The knowledge claims of scientific discourse are diverse. For example, a key aim ofbiologists working on cell structure is to describe as accurately as possible the structuresthat constitute cells. Thus, when biologists talk about cell membranes they are referring to acommonly agreed description of a structure that exists in the cell. However, not all entitiesof scientific discourse are descriptions of things that exist in the material world. Others, suchas inertia, are formally defined in terms of a system of related concepts. Given these kinds ofdifferences between scientific knowledge claims, it makes little sense to assume that thereis a single, universal account of the nature of scientific knowledge. Rather, people with asophisticated perspective on the nature of science are likely to have access to a numberof epistemological ideas, deployed according to the context. Indeed, there is evidence thatadvanced science learners do indeed draw upon a range of perspectives on the nature ofscience, and the challenge for teaching seems to be to enable students to draw upon thoseperspectives more appropriately in different contexts (Brickhouse et al., 2000; Leach et al.,2000). Therefore in designing the teaching activities, we wanted to present students with

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appropriate epistemological ideas relevant to a specific scientific context, and equip themto use those ideas in related contexts.

In England, the high school curriculum (for students aged 16–18) is highly specialized incomparison to the curricula studied by similar students in most other parts of the world. Atthe time when data were collected for this study (1999–2000), students between the agesof 16 and 18 typically studied only three subjects.1 Teachers tended to view syllabuses asoverloaded with content. We were advised by our teacher-collaborators that teachers wouldnot attempt teaching activities that demanded too much curriculum time. Furthermore, thereare no systematic structures in England through which professional development about newteaching materials can be provided. For these reasons, we decided to try to introduce epis-temological ideas into science courses through single lessons, providing science teacherswith suggestions about other areas of the syllabus where these issues could be followedup with students and providing written guidance about the use of the materials. It is worthunderlining that, for these pragmatic reasons, the teachers who participated in this study didnot undergo a formal training program prior to teaching the lessons. Rather, we attemptedto write guidance into the teaching materials ourselves. These conditions are typical ofthe situation encountered by most teachers, who pick up packages of curriculum materials“off the shelf” without the benefit of associated training. All the participating teachers inthe study however, did, attend meetings where ideas for the lessons were discussed andfeedback on drafts was received.

We began by identifying a range of possible activities and contexts that might be used toaddress the status of scientific theories with students. Initial versions of two lessons werethen developed in consultation with a group of local teachers. These were given a trialwith at least one class. The lessons were observed and audiorecorded in order to providefeedback about the extent to which teachers and students understood the lesson materials.The students involved in the trial lessons completed a questionnaire to elicit their reactionsto the lesson and the teacher was asked for feedback on how they felt about the lesson.The findings from the trials were discussed with the teacher group, and they were informedabout subsequent revisions to the lessons. The revised lessons were then implemented by asecond group of teachers, including the teachers in the development group.

The two lessons that were developed focused upon Maxwell’s original analogous modelof electromagnetism as a fluid, and the development of understanding of the structure ofcell membranes during the twentieth century. The materials that were developed consistedof resources for use in classrooms, strategies for the use of those resources, and guidancenotes for teachers.

Electromagnetism

This lesson is based on the development of James Clerk Maxwell’s model of electro-magnetism. The activities in this lesson focus on the use of abstract ideas and analogies indeveloping theoretical models. The first activity introduces the distinction between observ-able or measurable phenomena and the ideas that are used to explain them. The studentsare then presented with the story of how Maxwell developed a mathematical model of elec-tromagnetism by drawing an analogy between electromagnetic effects and fluids. Two keyelements are stressed in this presentation. These were the abstract nature of the model and therole of analogy in its conception, and the fruitfulness (and predictive success) of the modelat unifying theoretical ideas about light, electricity, and magnetism. In the final activity

1 The structure of the post-16 curriculum in England has been reviewed since data for this study werecollected.

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students work with the more accessible kinetic model of gases to highlight the usefulness ofmodels in making testable predictions that generate further research. This provides studentswith the opportunity to transfer the ideas they have learnt in the first part of the activity andto recognize how those ideas apply to conceptual content in their physics course.

Cell Membranes

The second lesson presents a history of the development of models of cell membranestructure. This model is different from Maxwell’s in that it aims to describe the relationshipbetween entities that exist in cells (lipids, proteins, and organelles). It demonstrates thenecessity of going beyond the available data in order to develop an understanding of therelationship between entities, and how the generation of models can provide a focus forfurther research.

The story is presented in three stages. At each point students are presented with a summaryof evidence about the structure of cell membranes that was available at a given point inhistory, together with an account of the models of membrane structure that were proposed.The first set of data is presented to students without any underlying model: the aim of thisis to start students interaction with the presented evidence in a critical way. The first twomodels are then presented, both of which are equally well supported by the available dataand both involve conjecture about the arrangement of proteins for which no evidence wasavailable. The point highlighted here is that the models that were developed went beyondavailable data and involved informed conjecture on the part of the scientists concerned.In the final activity, students are presented with new evidence and a new model, whichcorresponds to contemporary accounts of the structure of cell membranes. In this case, theevidence supports only one of the models. Through this sequence of historical snapshots,we aimed to communicate to students the way in which scientific models go beyond theavailable data. Models do not arise unproblematically from data, yet at the same time notall models are equally successful in explaining the available data.

Full sets of the teaching materials are available at www.nuffieldfoundation.org/aboutscience.

EVALUATION OF THE TEACHING

Evaluation of Students’ Learning

People with sophisticated epistemological knowledge are able to draw upon a range ofperspectives about the nature of science in a variety of contexts. Our aspiration for theseteaching sequences was therefore that, following teaching, we should be able to see someevidence that students were better able to articulate epistemological ideas, or to draw uponepistemological ideas more appropriately, in a given context. In order to evaluate students’learning as a result of teaching, we were interested in the extent to which they

• used a range of appropriate ways of thinking about a scientific context before andafter teaching;

• were able to articulate ideas about the nature of scientific knowledge claims beforeand after teaching;

• drew upon the context presented in the teaching to illustrate their responses in adifferent context, after teaching.

A written diagnostic question (hereafter referred to as “the probe”) was used with allstudents before and after teaching. The question does not involve electromagnetism or cell


membranes, though it does allow students to deploy epistemological ideas about the natureand status of scientific knowledge, which formed the focus of the teaching. To interpretstudents’ written responses, a subsample of students was interviewed about their responsesto the diagnostic question. This subsample was identified to represent diversity in responsesto the probe. This allowed us to probe the meanings ascribed by students to terms suchas “theory” and “model,” and to question students about apparent inconsistencies in theirresponses, as well as allowing us to get a qualitative sense of the students’ ability to articulateepistemological ideas. The probe was based on one used in previous research (Leach et al.,2000; Ryder & Leach, 2000) and was chosen because it offered the chance to highlight arange of appropriate views about the nature of science. The probe was piloted in the initialphase of the project. Wording was modified where it appeared ambiguous. The text of theprobe, as used in this study, can be found in the Appendix.

The probe is contextualized in solid state physics, and raises the question of how differentmodels can be compared and evaluated. The question is designed to find out on what basisstudents think that competing models can be evaluated. In particular, we were interestedin whether students assumed that there are always simple, empirical methods for evaluat-ing competing models, or whether they referred to more complex relationships betweenknowledge claims and data. Students were presented with two diagrams that showed therelationship between temperature and conductivity of the superconductor, as predicted bytwo different models. All data points are shown with associated error bars. In both cases, thepredicted relationship was empirically consistent in that the predicted curves fell within theerror bars. The theoretical models underpinning the proposed relationships between tem-perature and resistance are highly technical, and were not presented. Pairs of students wereasked to discuss their answers to the following question: “What courses of action do youthink that the scientists now need to follow in order to decide which theoretical model pro-vides the best interpretation of the data?” Following a short paired discussion each studentwas asked to write down his or her individual response to the question.

The next part of the question presented students with eight statements about what thescientists might do next. Each statement described a strategy that involved collecting moredata, or improving the quality of the available data, or examining the relationship betweenthe available data and the models. Students were asked to indicate whether they understoodclearly, understood partly, or did not understand the statements, and to classify the statementsas appropriate or inappropriate, or to indicate that they were unsure as to whether the strategywas appropriate or not. Finally, students were asked to choose one or two courses of actionas the best ones for the scientists to follow, and to explain their choice.

In this question, it might be expected that students who have fairly unsophisticated ideasabout the role of theoretical models in science would give responses that were focusedentirely on collecting more or better data (Ryder & Leach, 2000). By contrast, those withmore sophisticated ideas might suggest looking at internal characteristics of the models (inaddition to collecting more or better data). The coding scheme used to analyze students’responses identified the extent to which they referred to the internal characteristics of themodels:

O Students who do not give an open response which refers to the theory, model, assump-tions or approximations made by the two groups AND said either of the followingstatements were inappropriate courses of action or were unsure of their response.

• Examine the assumptions and approximations used by each of the groups in devel-oping their theoretical model.

• Examine the extent to which each theoretical model has successfully explained theelectrical resistance of other superconducting materials.

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C The statements above were accepted as appropriate courses of action but there was noresponse to the first part of the probe which refers to the theory, model, assumptions orapproximations made by the two groups. This category also includes any responses thatsuggest the student does not recognize the theoretical models used in this context, forexample, using the word “model” to refer to a line of best fit or data set, e.g. “Averagethe two models.”

B The statements above were accepted as appropriate courses of action AND their re-sponse to the first part of the probe states simply that the theory, models, assumptions orapproximations should be looked at. There is no elaboration of what might be involvedin “looking at the models,” OR the elaboration is simplistic in that it relates only to theterms presented in the text of the probe.

A As for category B but the response to the first part of the probe also includes some degreeof elaboration of what might be involved in “looking at the models.” The elaborationshould make clear the role of ideas in the models and not simply reiterate the termsused in the probe. For example, “compare theories, see where they differ and considerthe arguments” or “look at assumptions or approximations for both models to see ifany are invalid, making the model invalid.”

N Students with uninterpretable, contradictory, or incomplete responses to either the openor closed questions.

The distinction between responses coded B and A is one of elaboration. In reportingfindings in this paper, we have used examples of students’ words in an attempt to give asense of the distinction drawn between categories B and A.

In common with all written diagnostic instruments addressing epistemological questions(Leach et al., 2000; Lederman, Wade, & Bell, 1998), the probe has limitations. The proberequired students to read and assimilate a lot of information quickly. Although the proberequired students to comment upon two different models of superconductivity, technicaldetails of these models were not presented to students. Students who did not appear able toarticulate ideas about the models in this context may have articulated appropriate ideas ina simpler context.

Evaluation of the Issues Faced by Teachersin Implementing the Teaching

We were interested to find out what factors promoted or constrained the teachers’ abilitiesto implement teaching activities. This issue was evaluated informally using classroom dataand postteaching interviews. These interviews focused on the feelings the teachers hadabout the effectiveness of the lesson and the challenges they perceived in teaching thelessons for the first time. Teachers were asked what they thought the benefits to students inundertaking these activities might be.

Sample Details

The Electromagnetism lesson was implemented in three classes taught by the three physicsteachers who were members of the development group. The student sample, therefore,comprised all students in those teachers’ A-level science classes, involving 35 students intotal. The Cell Membranes lesson was implemented in three classes taught by the threebiology teachers who were members of the development group. The sample also consistsof 35 students. The classes were drawn from schools in urban and suburban areas in theNorth of England, serving lower- to middle-income communities.


TABLE 1Sample Details

Number of Students Returning Number of Studentsn Both Pre- and Postteaching Evaluations Interviewed

Electromagnetism 35 27 6Cell membranes 35 18 4

The number of students who completed the probe both pre- and postteaching are shownin Table 1.

The low number of returns in the case of the Cell Membranes lesson is due to the levelof absence of students in one or more of the lessons where diagnostic questions wereadministered.

STUDENTS’ LEARNING

A remarkably similar pattern in students’ responses was seen across the Electromagnetismand Cell Membranes lessons. Therefore, given limitations in the sample size for the CellMembranes lesson, we will focus upon quantitative data from the Electromagnetism lesson.The changes in students’ responses between the pre- and posttest are summarized in Figure 1.The three students in the sample whose responses were uninterpretable (coded N) have beenomitted from Figure 1. Of the 18 students who did not mention the importance of examiningthe theoretical models in the pretest explicitly (coded O or C), 9 made a more sophisticatedresponse (i.e. A or B) after teaching. However, 6 of the 10 students coded as O in the pretest,and 3 of the 8 coded C, showed little or no progress.

Lines have been drawn with different thickness to indicate the main pathways of move-ment. Interviews with students provide some insights into the development that took placein their understanding of the role of theoretical models. The interviews that were conductedwith students who had studied both the Electromagnetism and Cell Membranes lessonsraised similar issues.

Data from the written probe showed that a significant number of students demonstrated adevelopment in their articulation of ideas about theoretical models. These students were ableto articulate views in the interview that showed recognition of the importance of generatingmodels. The following extract is taken from a student who referred to the interrelationship

Figure 1. Changes in students’ responses for the “Electromagnetism” lesson.

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of data and models after teaching, but who had referred to data alone before teaching:

Student V I think they should go and have a look at what assumptions and things they’vemade because if they’ve made different ones, you see, it’ll just throw them bothtotally in different directions won’t it? (Electromagnetism V 5)

However, the extent to which students were able to communicate what it might mean toexamine the models was more variable. Only one student in the interview sample was ableto describe what the approximations and assumptions in this context might involve. In somecases, students who said it would be appropriate to examine the model then gave a confusedaccount of what this might mean. When questioned during the interview, they returned tomore secure views about the value of getting better data to determine which was the bettermodel.

There was a significant group of students who appeared to show no development in theirunderstanding in response to the teaching. In particular, about half the students who statedit was inappropriate to examine either the theoretical model itself or the approximationsand assumptions used in developing the model, held this view after the teaching. We haveidentified two issues that appeared to serve as barriers to such students in developing moreappropriate ideas about theoretical models.

Issue 1: Recognizing the Epistemological Issues at Stakein the Lesson

During the interviews, it was apparent that some students had recognized the centralissues at stake in the lesson, and were able to articulate epistemological ideas after thelessons. The lessons had achieved their aim of “opening up” epistemological issues withsuch students. Student X, who gave a very thoughtful account of the role of models in theinterview, illustrates this in describing the aim of the lesson as teaching about models:

Interviewer What do you think [the teacher] wanted you to learn in the lesson?Student X One of the things—to understand ( . . . ) that a model, it’s not, it will never

be able to explain actually what is happening. That sounds a bit strange butwhat it is, it’s giving you example of something that represents it happening.Like you can’t visualize like a magnetic field or something but you can makemodels which, if something that we can see and understand, that simulatesthat effect. That’s not actually what happens but that’s how we can representit. (Electromagnetism X 14)

However, a number of students made no apparent progress in their ability to recognize andarticulate epistemological ideas as a result of the teaching, and were not able to say anythingin response to interview questions about the aims of the teaching. Interestingly, however,classroom observation suggested that such students appeared able to perform individualactivities during the teaching, indicating a possible basis for development in future lessons.

Issue 2: Recognizing Theoretical Models in Different Contexts

During teaching, most students appeared to be able to talk about models of cell mem-branes, Maxwell’s models, and the kinetic model of matter. However, this knowledge wasnot transferred to the problems posed in the graphs probe by a significant number of students.Such students seemed unable to recognize the distinction that was being drawn in the textof the probe between models, predicted values, and data. During interviews, some students


appeared to recognize a conflict between the interpretations of the LIS and COAST groups,but did not appear to make a distinction between the underlying models of superconductiv-ity, and data about the behavior of materials. For example, several students suggested thatthe scientists could reach closure by “averaging the models”:

Student Z Erm . . . I think they should draw up another model and then they should takean average of all of the models from all the different groups and then that’llgive them a more accurate model to go by and then they should use that modelas the final one. (Electromagnetism Z 3)

Similar reasoning has been noted in response to a variety of other contexts (Sere et al.,2001).

Other students suggested that the conflict could be solved through social mechanisms,with little mention of how social and empirical processes might interact. Responses relatingto the scientists “getting together” to “share ideas or resources” were common. This kindof thinking can be seen in the responses given by the following student:

Interviewer Any other things that the scientists might need to do next?Student U They could look at other models from other groups to see if some agree with

one more than other.Interviewer Right. So why would they do that?

Student U To get more opinions, different viewpoints. See if one agrees more with oneof the models.

Interviewer Right, okay.Student U See [if ] it’s of the majority really. (Electromagnetism U 6)

There seems to be a significant group of students who are not able to differentiate clearlybetween models based on theoretical ideas and data collected through experimental mea-surements. We are not surprised to find that, for these students, a single lesson is not sufficientto give them an understanding of the role of theoretical models. It seems that some studentsare so unclear about the distinction between the models presented to them and experimentaldata that they are not able to grasp the teaching points of the kind of activities developedby this study.

TEACHERS AND TEACHING

In addition to evaluating student learning, we also examined teachers’ experiences ofteaching about the nature of science during high school science courses. A number ofissues were identified through observations of the lessons and informal discussions withteachers in the pilot phase of the project. The issues were followed up in interviews withteachers after they had taught the lessons.

Issues of Teacher Knowledge and Confidence

It was clear from interviews with the teachers involved in this study that most found theteaching challenging and unfamiliar. Several described the difficulties in teaching issuesthat they did not feel confident about. Some teachers stated that their lack of confidence intheir own knowledge about the nature of science was a problem during the teaching. Theyconsidered it important to teach the ideas presented in the lesson but found it difficult tofocus the teaching on the aims of the lesson. This seemed to be because the ideas presentedwere not ones that they tended to think about during their normal practice. Unsurprisingly,

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our observations of lessons suggested that aims were communicated more explicitly inteaching when teachers were more confident of their own knowledge about the content.

The inclusion of teaching aims relating to the nature of science in examination syllabusesand initial teacher training curricula is relatively recent in England. As a result many teachershave no experience of teaching the issues identified in this project nor have they had anytraining, either about the issues themselves (often given little mention on undergraduatescience courses) or how to teach them. On the advice of teachers in the development group,we attempted to design the materials in a way that recognised that most teachers havelittle experience of teaching about the nature of science. The lessons and the guidancegiven to teachers were designed to provide a starting point for treatment of the nature ofscience issues during high school science courses. We are encouraged that all the teachersinterviewed said they would use the lesson they implemented again in their courses, usuallyin an adapted form to suit their needs.

Teachers Saw the Type of Activities Developed in the Lessons as Novel

In order to encourage students to engage with the ideas presented to them, there was anemphasis on student–student interactions in the activities. The teaching activities tended toinvolve students responding to a context through paired discussion, followed by a clearlyfocused pulling together of their ideas by the teacher. The aim of the paired discussion wasto prime students for a focused intervention from the teacher by getting them to think aboutthe issues. For example, in the Electromagnetism lesson, the students are asked to place anumber of statements on a scale from “real phenomena” to “abstract ideas.” The purposeof this is to stimulate students to think about abstract ideas before the teacher developsthe issue of the role of abstract ideas and analogies in science. Observations of the lessonsshowed that this aspect of the lessons was more effective when the teacher kept the paireddiscussion short. In this case the students were able to engage with the issue and developtheir own ideas sufficiently to enable them to recognise the points made by the teacher inthe lesson. However, some teachers stated that they experienced a conflict between the shorttime suggested for the discussion and a sense that they did not want to interrupt discussionbefore students exhausted all their ideas.

A further issue arising from observations of the lessons was the problem of dealingwith “wrong answers.” The lessons have very clear teaching objectives, yet in many casesteachers were reluctant to tackle explicitly ideas offered by the students that contradictedthe teaching aims of the lesson. This is possibly due to issues of teacher knowledge andconfidence. In interviews teachers were hesitant in stating that ideas could be judged as“better” or “worse” than others in the context of lessons about the epistemology in sci-ence. Some of the teachers in the study also expressed the need to handle students’ sug-gestions sensitively, which in some cases may have led to an ambiguous response fromthe teacher during teaching. Furthermore, interviews suggested that many were reluctantto identify inappropriate ideas during whole class discussions because this would inhibitcontributions:

I know that certain people in that class are very shy of appearing wrong and ( . . . ) they’lljust stop interacting if they think they’re going to get it wrong. So I didn’t want to say tothem well no, that’s not the direction that this is going in, or no that’s wrong. (A. 10)

The (inappropriate) message that there are “no better or worse ways of talking abouta given situation in science” was presented through the teaching on more than oneoccasion.


Teachers Often Stated That the Teaching Aims of the LessonsWould Be Reinforced in Subsequent Teaching

Several of the teachers interviewed stated that one of the potential benefits of theselessons was in providing a reference point to draw upon later in the course. Examples givenin interviews included drawing upon the experiences of the Electromagnetism lesson whenteaching other theoretical models on the physics curriculum, and referring back to the CellMembranes activity when teaching plant transport theory and the DNA molecular model.This evidence suggests that the teaching was successful in “opening up” conversations aboutepistemological ideas between teachers and students.

Teachers Generally Appeared Motivated by the Lessons

The overall feeling expressed by teachers in the interviews was that the lessons wereeffective. They saw the ideas taught in the lessons as worthwhile. The only caveat to thiswas a sense that teachers felt under a great deal of pressure to get through the content ofhigh-school courses. Often the lessons were well received in part because they are shortteaching sequences of an hour or less. However, all the teachers interviewed said they feltthe lesson was worthwhile and would use it again in some form. In some cases teachersvalued the novelty of the activities; they appreciated the kind of thinking and discussionthat was a part of the lessons.

CONCLUSIONS

The purpose of these two teaching interventions was to introduce basic epistemologicalideas about the nature and status of particular items of theoretical knowledge in science,to enable students to recognise the contexts in which particular forms of epistemologi-cal reasoning are appropriate, and to articulate epistemological ideas more clearly. Howsuccessful was the teaching in achieving this aim? Some students certainly did improvetheir ability to articulate some basic epistemological ideas following teaching, and wereable to draw upon a wider range of perspectives about the nature of science in a particu-lar context. However, for many of these students, new ideas about the role of theoreticalmodels were very tentative compared to more confident views about the importance ofcollecting empirical data. Furthermore, a significant number of students did not appear tounderstand what the lessons were about, and apparently made no progress. At this level,the teaching can hardly be judged to have been successful in providing students with amore sophisticated understanding of the nature of science. However, it would be naıveto expect to see radical changes in students’ epistemological reasoning following inter-ventions that only last for one lesson. The fact that some students were better able toarticulate epistemological issues at the end of the teaching is maybe as much as can beexpected.

However, the fact that a significant number of students did not appear to appreciate theaim of the lessons, or make any progress following teaching, raises important questions.In previous work (Leach et al., 2000; Ryder, Leach, & Driver, 1998) we have suggestedthat, at the university level, students are already able to engage with epistemological is-sues, but often do so inappropriately. The teaching issue therefore seems to involve helpinguniversity students to use epistemological reasoning more appropriately according to con-text. However, a significant number of students in this study did not appear able to engagewith the epistemological issues that were presented in the teaching. This suggests that theteaching issue may well be different for many 16–18 year old high school science students,

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requiring epistemological issues to be problematized. Although the teaching approach usedin this study was not successful in achieving this aim for some students, it is interesting tonote that many of the students who did not appear to make progress nonetheless appearedable to perform the tasks required by the teaching activities. One possible teaching strategymight therefore involve a “drip feed” approach to introducing students to epistemologi-cal issues, with short teaching interventions being used throughout junior high-school andhigh-school science course. This strategy has the added advantage of allowing students tomake links between epistemological and conceptual ideas introduced through the sciencecurriculum.

Overall, teachers’ responses to the materials were very positive. The majority of theteachers who were asked to pilot the materials stated that it was worthwhile to teachstudents about the nature of scientific knowledge. Moreover, they were clear that mate-rials that supported them in addressing students’ understanding of the nature of scientificknowledge would be essential if they were to tackle this effectively. On the few occasionswhen teachers were reluctant to implement the materials, the reason given was lack oftime.

However, there was a marked lack of confidence on the part of most of the teachers inimplementing the materials. This was for a variety of reasons. Several teachers were notconfident about their personal understanding of the issues in question. For some, the issuesaddressed by the materials were ones to which they had given little previous thought. Inspite of participation in the development group some teachers communicated inappropriatemessages about the nature of science during the teaching.

Some teachers found the students’ ideas about the nature of science difficult to deal within the classroom. There was a feeling amongst some of the teachers that they were notconfident to tackle ideas from the students that were clearly wrong or inappropriate. Insteadthere was a sense that the teacher felt the discussion of individual ideas was more importantthan pointing out inappropriate ideas and guiding students towards a more sophisticatedviewpoint.

The success of the lessons, in students’ eyes, was closely related to whether the teacherstated explicitly the aims of the lessons. In observing the teaching, we were conscious ofthe diversity of teachers’ understanding about the aims of the lessons. This was reflectedin the ways that they handled classroom discussion. Those who were clear about the aimsof the lessons kept discussion focused on the aims of the teaching. Others, who were lessclear about the aims of the teaching, did not appear to guide classroom discussion. Further-more, such teachers occasionally made statements to students that could be interpreted asindicating an extreme relativist position. Such teachers did not generally attempt to provideany sort of closure on student discussions. Unsurprisingly, many students were unclear asto what they were supposed to have learnt during the lesson.

An obvious research agenda emerging from this study is to investigate whether teachersdid indeed use the lessons as points of reference in subsequent science teaching. Recentpreliminary work by one of us has addressed this issue (Hind, 2002). A longitudinal studywas conducted in which two teachers used one or two of the designed lessons with theirhigh-school science groups, and were asked to develop the themes introduced in subsequentteaching. Students in the groups completed the probe at the beginning, and the end, of thewhole year’s teaching. Similar baseline information was collected from similar (though notstatistically comparable) groups. The two teachers who form the subject of the case studydid make references to the lessons, and their content, in subsequent teaching, indicatingthat the single lessons can act as “seeds” for raising epistemic issues within the A-levelcourse. However, the teachers did not develop more formal interventions. Interestingly,the difference between students’ responses to the probe at the end of the year compared


to the beginning of the year was broadly similar to the differences before and after onelesson noted in this study. However, these gains in learning were sustained over a wholeyear. Such gains are unlikely to be the product of test effects. No significant differenceswere noted between students’ responses at the beginning and end of the year in baselinegroups.

In future work, we are interested to find out more about the relationship between teachers’own epistemological knowledge, and the ways in which they implement teaching with anepistemological focus.

APPENDIX: PROBE USED TO ASSESS STUDENTS’ LEARNING

Interpreting Data

This question is about a real issue being worked on by scientists at the moment. In orderto answer this question, you do not need to understand the technical details of the scientistswork: the main focus of the question is upon the ways in which scientific data are analyzedand interpreted.

Superconductors are very special materials. Using superconductors to transfer electricityaround the country could lead to a significant reduction in energy consumption. This isbecause these materials have zero resistance to electricity at low temperatures.

Several groups of scientists around the world are investigating the properties of a newsuperconductor. Some of these groups are trying to give a theoretical explanation of howthe electrical resistance of this material falls as the temperature is lowered. These theoreticalexplanations involve the development of a theoretical model of how the superconductorcarries electrical current, and how this behavior changes as the temperature is lowered.

These theoretical models are developed using insights into the microscopic structureof the material. In developing these theoretical models scientists need to make approxi-mations and assumptions about the behavior of the material. They also need to be cre-ative in the way that they think about the material. Scientists often draw analogies withother materials with which they are familiar in developing theoretical models for newmaterials.

The LIS group have developed their own theoretical model to explain the fall in electricalresistance of this new material. The LIS model predicts that the fall in electrical resistanceof the material as the temperature is lowered will follow the trend shown by the line on thediagram below:

844 LEACH ET AL.

The COAST group have developed a different theoretical model to explain the fall inelectrical resistance of this new material. The COAST model predicts that the fall in electricalresistance of the material as the temperature is lowered will follow the trend shown by theline on the diagram below:

Another group of scientists has measured the electrical resistance of this superconductoras the temperature is changed. The investigation was performed under carefully controlledconditions, and other scientists have been able to repeat the measurements in their ownlaboratories and get virtually identical results. The results, with error bars, are given below:

The theoretical model developed by the LIS group generates a line which passes throughall of these error bars:

Similarly, the theoretical model developed by the COAST group generates a line whichpasses through all of these error bars:


Scientists from the LIS and COAST groups, and also scientists from other groups, havecome together at a conference meeting in order to decide what to do next.

Paired Student Discussion

You have 5–10 minutes to discuss the following question with your partner:

⇒ What courses of action do you think that the scientists now need to follow in orderto decide which theoretical model provides the best interpretation of the data?

Your teacher will ask you to stop your discussion after 5–10 minutes.

You will then be asked to write your own answer to the following question.

Question 1

⇒ Using the space provided describe possible courses of action that you think thescientists now need to follow in order to decide which theoretical model providesthe best interpretation of the data?

⇒ In each case explain why you think this is an appropriate course of action.⇒ Give as many courses of action as you can think of. Continue on the reverse side of

this paper if necessary.

When you have done this decide which ONE of the above courses of action you thinkwould be the most important thing to do next?

Please circle the response you have given that you think is most important.

[space was provided here for extended answers by students]

Please circle the response you have given that you think is most important.

Question 2

Answer this question without discussing your answer with anyone else.Listed below are a number possible courses of action for what the scientists could do

next. For each statement indicate whether,

i) You understand what the scientists are suggesting.ii) You think their suggestion is useful or not.

846 LEACH ET AL.

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and

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848 LEACH ET AL.

In the box below give the letter(s) of one or two statements which you feel are the mostimportant things to do next.

[space was provided here for student responses]

Explain below why you think that this choice (or choices) is the most important thing to donext.

[space was provided here for extended answers by students]

The authors acknowledge the contribution of many teachers to the development of the materialsreported in this paper. Ned Prideaux and Tricia Coombe made particularly significant contributions.

REFERENCES

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Brickhouse, N. W., Dagher, Z. R., Letts, W. J., IV, & Shipman, H. L. (2000). Diversity of students’views about evidence, theory and the interface between science and religion in an astronomy course.Journal of Research in Science Teaching, 37(4), 340–362.

Desautels, J., & Larochelle, M. (1998). The epistemology of students: The “thingified” nature ofscientific knowledge. In B. Frazer & K. Tobin (Eds.), International handbook of science education.Dordrecht, The Netherlands: Kluwer.

Driver, R., Leach, J., Millar, R., & Scott, P. (1996). Young people’s images of science. Buckingham,England: Open University Press.

Hind, A. J. (2002). Teaching and learning about the nature of scientific theoretical models as partof an AS level programme of study. Unpublished M.Ed. Thesis, The University of Leeds, Leeds,United Kingdom.

Leach, J., Millar, R., Ryder, R., & Sere, M.-G. (2000). Epistemological understanding in sciencelearning: The consistency of representations across contexts. Learning and Instruction, 10(6), 497–527.

Lederman, N. G., & O’Malley, M. (1990). Students’ perceptions of tentativeness in science: Devel-opment, use and sources of change. Science Education, 74, 225–239.

Lederman, N., Wade, P., & Bell, R. L. (1998). Assessing understanding of the nature of science: Ahistorical perspective. In W. McComas (Ed.), The nature of science in science education: Rationalesand strategies (pp. 83–126). Dordrecht, The Netherlands: Kluwer.

Millar, R. (1996). Towards a science curriculum for public understanding. School Science Review,77, 7–18.

Millar, R., & Osborne, J. (Eds.) (1998). Beyond 2000: Science education for the future. London:King’s College London.

NRC. (1995). National Science Education Standards. National Committee on Science EducationStandards and Assessment. Downloaded from http://www.nationalacademies.org/subjectindex/edu.html on 21 March 2001.

Ryder, J., Leach, J., & Driver, R. (1999). Undergraduate science students’ images of science. Journalof Research in Science Teaching, 36, 201–219.

Ryder, J., & Leach, J. (2000). Interpreting experimental data: The views of upper secondary schooland university science students. International Journal of Science Education, 22(10), 1069–1084.

Sere, M.-G., Fernandez-Gonzalez, M., Gallegos, J. A., Gonzalez-Garcia, F., De Manueal, E., JavierPerales, F., & Leach, J. (2001). Images of science linked to labwork: A survey of secondary schooland university students. Research In Science Education, 31(4), 499–523.

Smith, M. U., & Scharmann, L. C. (1999). Defining versus describing: A pragmatic analysis forclassroom teachers and science educators. Science Education, 83, 493–509.

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