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An introduction to physics educationresearch

Jan van Aalst

Abstract: At a number of U.S. universities, some physicists are focusing their research efforton physics education research (PER). This paper examines this development in terms of theknowledge of teaching and learning, curriculum projects and practices it has produced. First, aselective review of research and curriculum development projects provides an introduction toPER for readers unfamiliar with it. Studies based on surveys and interviews are emphasized,as well as curriculum projects that make use of microcomputer-based laboratory tools (MBL).Other efforts are mentioned more briefly, but illustrate the breath of research and developmentactivity. Following the review, I examine the evidence for the effectiveness of some of thecurricula discussed, and identify three areas in which greater interaction between the PER andeducational researchers working in other fields should be fostered: (a) statistical data analysis,(b) micro-analysis of learning situations, and (c) ways in which subject matter knowledgein physics can contribute to school-based projects and educational research. The concludingsection of the paper argues for multi-disciplinary graduate programs in physics education,which are intended to provide a solid base in physics as well as research and innovation ineducation.

PACS Nos.: 01.40.Fk, 01.50.Ht

Résumé: Dans plusieurs universités américaines, des physiciens concentrent leurs efforts derecherche sur l’enseignement de la physique (REP). Nous examinons ici ce développementpar l’amélioration de notre connaissance de l’enseignement et de l’apprentissage et des projetsde programmes et des pratiques qui en ont découlé. Dans un premier temps, une revue cibléede la recherche et de projets de développement de programmes fournit une introduction à laREP pour ceux qui ne sont pas familiers avec le domaine. Nous favorisons les études baséessur les sondages et les interviews, aussi bien que sur les projets de programme utilisant lemicro-ordinateur comme outil de laboratoire. D’autres efforts sont mentionnés brièvement,mais seulement pour illustrer l’ampleur des activités de recherche et de développement. Aprèscette revue, nous examinons les indicateurs d’efficacité de certains des programmes proposés etidentifions trois domaines dans lesquels on devrait favoriser une plus grande interaction entreles chercheurs en REP et les chercheurs en enseignement dans d’autres champs : (a) l’analysestatistique des données, (b) la micro-analyse de situation d’apprentissage et (c) les moyenspar lesquels les connaissances en physique peuvent contribuer aux projets et à la rechercheen éducation au sein de l’école. La conclusion de ce papier prône la création de programmesgradués multi-disciplinaires en enseignement de la physique, visant à fournir une base solideaussi bien en physique qu’en recherche et en innovation dans l’ enseignement de la physique.[Traduit par la rédaction]

Received August 13, 1999. Accepted January 19, 2000.

J. van Aalst .1 Department of Physics, University of Toronto, 60 St. George Street, Toronto, ON M5S 1A7,Canada.

1 Address after September 1, 1999: Faculty of Education, Simon Fraser University, 8888 University Drive,Burnaby, BC V5A 1S6, Canada.e-mail: vanaalst@sfu.ca

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1. Introduction

In the last 25 years, a number of physics departments in U.S.A. universities have established groups andgraduate programs that focus on Physics Education Research (PER)2. Redish and Steinberg [1] arguethat physics education research is an “emerging subfield of physics.” The aims of this review article areto provide an introduction to PER, to examine its current strengths and weaknesses, and its potentialcontribution to science education in general. It is focused on introductory physics, and is organizedaround four questions:

i What has PER contributed so far to knowledge about teaching and learning physics?

ii What teaching innovations has it produced?

iii How does it fit with traditional activities in physics departments?

iv What roles can it play in sustainable efforts to improve science education in elementary andsecondary schools?

2. Research on learning physics

2.1. Attitudes toward physics courses

One factor contributing to reforms in physics education in the U.S. has been a concern with decliningenrollment in university science programs [2, 3]. Consequently, a number of studies have examined whyacademically competent students avoid university science courses or leave science for other majors:the so-calledsecond tierof students whom we might expect to succeed in science. In a case study byTobias [4], seven graduate students and professors in the humanities who had not previously completeda university science course took one, and documented their reflections on their experiences in diariesand reflection papers. Tobias reported the following “student” perceptions about the courses.

• The big picture was lacking until the very end of the course.

• Students disliked the lack of community caused by strong competition for marks and a lack ofdiscussion in class.

• There was not enough emphasis on conceptual understanding, and not enough time to enjoysuccess.

• Almost all exam questions required only a single concept: nearly all students expected a finalexam that also requiredevaluationandsynthesisof ideas.

The study was based on a small number of students, but the results were corroborated by other studies: theLipton study [4], which followed second-tier students through all four years of their college education,and a similar study by Seymour and Hewitt [5]. In the Lipton study, even a significant number of studentswho remainedscience majors revealed a negative perception of the classroom climate. In explainingdifficulty with the subject, science majors blamed the nature of the subject matter; those who left quotedtheir own inadequacy. Some students who left indicated that they did not reject science itself, only thecompetitive nature of science courses.

2 A partial list of universities where physicists focus on PER can be obtained from the first Physics Education ResearchSupplement, Am. J. Phys.67(7), (1999); a reasonably complete list of WWW sites is provided by the PER group at theUniversity of Maryland, College Park campus, http://www.physics.umd.edu/

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Fig. 1. Series circuit question. Students are asked to compare the brightness of bulbs A, B, and C.

2.2. Studies of student conceptions

A different line of research has examined the ideas students use in explaining the physical and naturalworld. Many studies have used a protocol in which students are asked to think aloud as they answerquestions about a problem situation, usually involving apparatus; other studies of student conceptionshave used questionnaires. In the 1980s, there were three conferences at Cornell University on studentconceptions in science and mathematics, and a bibliography of studies of this kind had reached 4500studies by 1998 [6].3 In university physics, work with the think-aloud protocol in this strand by theUniversity of Washington Physics Education Group, first directed by Arons and then by McDermott,has been influential. In a 1990 Millikan lecture, McDermott [9] stressed that a substantial gap existsbetween what lecturers think they have taught and what is learned.

Surveys provide less information about student conceptions than think-aloud protocols, but theyhave the advantage that they can provide data on large samples, drawn from many institutions, andthereby give an indication of the generalizability of findings from think-aloud protocol studies. Perhapsthe best known examples of surveys are theForce concept inventory(FCI) [10] and theMechanicsbaseline test(MBT) [11]. Both published in 1992, these tests were developed from an earlier test,the Mechanics diagnoser[12, 13]. The FCI is purported to probe aspects of a single concept (force)qualitatively, while the Mechanics Baseline Test focuses on solving simple problems that require arange of mechanics concepts. There is now a variety of tests for motion and force available, such as theForce and motion conceptual evaluation(FMCE) developed by Thornton and Sokoloff [14] and theTestof understanding [kinematics] graphsby Beichner [15]. Tests for electromagnetism and the statisticaltreatment of uncertainty and experimental errors are being field tested.4

An important benefit of think-aloud protocols and survey research has been the development ofconceptual questionsthat can be used for diagnostic purposes. Such questions can be eye openers forprofessors: while theyappear to be much too simple for university students, student answers proveotherwise. Many professors are shocked when they see results obtained from their own students. Forexample, when a sample of approximately 200 students at the University of Toronto were asked torank the brightness of the light bulbs in Fig. 1, only 51% did it correctly at the end of their first-yearcourse — the same percentage as at the beginning; only 18% of students answered a similar question

3 The literature on science education often refers to student conceptions that are incongruent with scientific conceptions as “mis-conceptions.” Because such conceptions both have served students well in everyday life and can result from misinformation,many researchers have attempted to abolish the term in favor of more charitable expressions such as “preconceptions” [7] or“alternate conceptions” [8]. However, the latter of these has the considerable difficulty that it may suggest that science is “justanother point of view.”

4 Contact C. Hieggelke at Joliet Junior College for the former and R. Beichner at North Carolina State University (RaleighCampus) for the latter work, which is being completed by his graduate student D. Deardorff.

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Fig. 2. Exam question on electric circuits. The percentages show the fraction of the class who selecteda particular choice.

involving a parallel circuit correctly (also after instruction). Moreover, these results were not betterfor students who had done an experiment on dc circuits. The question shown in Fig. 2 was given ona final exam that immediately followed lectures on electromagnetism (the same students). Only 30%of 950 students answered this question correctly; 22% made choice No. 3, which suggests that thesestudents had difficulty determining what was in series and what in parallel in this circuit.5 Such resultsare neither limited to electric circuits, nor to this student sample. Hestenes et al. [10] showed that theresults on the FCI are to a large extent instructor-independent if traditional teaching methods are used.Thornton and Sokoloff [14] reported that responses to conceptual questions on their FMCE are virtuallyunchanged after traditional instruction — most questions are answered correctly by only 20% to 30%of students after traditional instruction.

How can information obtained from such questions be used to guide teaching? First, it provides away for the instructor forbecoming awareof the ideas students are using. Many of these ideas are notaccessed by traditional learning tasks and exams. If conceptual questions are used immediately afterinstruction, they can provide valuable feedback that allows a lecturer to make midcourse adjustmentssuch as explaining an example in another way or discussing an additional example. Conceptual questionsare best if the distracters provide information about which models, if any, students are likely to be usingin their reasoning. For example, Shipstone [16] discusses several alternative models students use toreason about electric circuits. If we have good evidence that students imagine current as being “usedup” as it passes through a circuit, we can attempt to design instruction that makes inadequacies in suchreasoning salient. But while individual questions can yield insight into a class’s ideas on a particularoccasion, they do not provide adequate evidence for scientific (e.g., Newtonian) reasoning. Students mayunderstand Newton’s third law but not think that it applies to the situation at hand. Kuhn [17] has arguedthat students “vacillate” between explanatory models before they use a new model consistently. For thisreason, Hestenes et al. [10] recommended that thetotal scoreon their FCI be used for assessing studentthinking about force. According to them, the FCI probes six essential aspects of a single concept,Newtonian force. There must be evidence for Newtonian thinking with respect to all six, of theseand consistency between the questions that access any given aspect. Huffman and Heller [18] foundfrom a study of the correlations between the percentages of students who answer each FCI question

5 J. vanAalst and R. Marjoribanks. Introducing research-based innovation into physics teaching:A case study of peer instruction.Manuscript in preparation.

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correctly thatstudentsmay not see the force concept as comprising the six aspects. According to theiranalysis, students see the questions as only related to each other in a loose sense.6 The FMCE Thorntonand Sokoloff [14] stresses the demand for consistency more than the FCI does, for example, by alsovarying themodalityof questions. Some questions use only “natural language” (text), while others alsomake reference to coordinate systems and graphs. There should be evidence for consistent Newtonianreasoning across these modalities.

2.3. Epistemological beliefsA third area of research is focused on epistemological beliefs (or assumptions) and how they influencelearning. Think-aloud studies by diSessa [21] and Hammer [22] suggest that students do not developcoherent physics knowledge but often see physics as consisting of more or less unrelated knowledgepieces. Building on these studies, and on research on expertise, Redish et al. [23] developed a surveyto examine six aspects of student expectations about learning physics:

(a) knowledge as authority-based versus uncertain and constructed, using evidence,

(b) physics as a coherent knowledge system versus a loose collection of ideas,

(c) physics as concept-based versus formula-based,

(d) mathematical equations as representing relationships between variables versus a computationalconvenience,

(e) physics knowledge as relevant to understanding students’ experiences in the world, and

(f) information presented in learning situations as requiring evaluation and interpretation.

The survey asks students to indicate the level of agreement with 34 statements that probe the six aspects,and the agreement levels are compared with those of college physics professors. As expected, first-yearstudent responses differ substantially from professor responses, but van Aalst and Key [24] found thatthere are substantial differences between courses that appear to be related to career goals — studentswho intend to major in the health sciences have views that are up to 20% less congruent with professorviews than students who intend to major in engineering.

3. Curriculum development

Although the studies described in the previous section have not led to adetailedunderstanding of learningphysics, they have influenced the development of a number of successful educational innovations. Inthis section, I describe some of these in detail and mention others more briefly to provide additionalaccess to the literature. Of course, what I have chosen to present in detail is in part a reflection ofmy own experience in physics education, not necessarily of the relative merit of the innovations. Thesection concludes with a discussion of the impact these innovations have made on physics learning andeducational research.

3.1. Workshop Physics and related projectsTwo influential curriculum development projects are theWorkshop physics project, directed by Lawsat Dickinson College, [25, 26] andTools for scientific thinking, directed by Thornton at Tufts Univer-sity and Sokoloff at the University of Oregon [27, 28]. In theWorkshop physics project, lectures are

6 For further discussion of the validity of the FCI, see a rebuttal by Hestenes and Halloun [19] and a rejoinder by Heller andHuffman [20].

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abolished and replaced by a program in which the presentation of new content, problem solving, andlaboratory activities are integrated into a coherent whole. During the year, students assume progres-sively more responsibility for designing their own investigations. While theWorkshop physics projectis suitable for small-enrollment settings like high schools and colleges,Tools for scientific thinkingisdesigned for courses in which lectures are retained: in the laboratory, students work through a so-called“guided inquiry” sequence. Both approaches make use of sensors connected to computers (so-calledmicrocomputer-based laboratory (MBL) tools), which allowreal-timedata acquisition, analysis, andpresentation. One advantage of these tools is that students can see graphswhile they are involved inphysical actions (e.g., walking or moving a glider over an air-track): this makes it easier to connect thegraphs to these actions. Another advantage is that students can, in the time they have available, workwith concepts in more diverse problem contexts: they spend less time collecting and recording data,and doing repetitive calculations, and have more time for interpreting and discussing the data. Finally,MBL tools can illustrate ideas that are difficult to visualize.

TheWorkshop physics projecthas been adapted for use in a variety of educational settings. As anexample, I describe a sequence of activities of integrated mechanics curriculum materials I developedfor a course intended for university students who have not taken Grade 13 physics before.7 The activitiesgradually address an idea difficult for many students: if an object is thrown vertically upward and allowedto fall down again, the acceleration at the highest point is not zero, although the velocity is. Using MBL,students begin by plottingx–t andv–t graphs of their own motion in real time, thereby developingunderstanding of motion in two “worlds”: thephysical worldin which the motion is taking place, andtherepresentational worldof the graphs. Students can see, for example, that when they walk faster infront of the motion detector, the slope of theirx–t graph increases, as does the height of the curve on thev–t graph. They can be guided to see that at the point they turn around,x is a maximum or minimum andv passes through zero. (This activity helps to demystify the MBL tools to some extent, so that studentsdevelop understanding of what they are doing.) In a follow-up activity, students extend their inquiry toa–t graphs. They use a cart to improve the signal-to-noise ratio of the data. At this point, the kinematicequations are introduced and students use them to solve some textbook problems. One such probleminvolves calculating the time interval after which a cart that passedx = 0 while moving up an inclinedramp, will return to that point movingdownthe ramp. Students first obtain an answer using MBL tools,and then calculate the result. In doing so, they confirm the features of thex–t andv–t graphs they hadlearned from motion involving their bodies, and see that when the cart turns around, the accelerationis not zero. (Of course, having seen this result, it requires an explanation.) If the kinematic equationswere inducted from motion that did not involve turning around, they now see that they also apply tothat situation. Finally, after some experience with the kinematic equations, students solve a problem inwhich they are to explain why a basketball player seems to “hang” near the high point of the jump. Inthis case, they use an electronic spreadsheet tomodelthe jump, so that they can conclude that regardlessof the initial velocity or maximum height of the jump, (approximately) 50% of the jump time is spentin the highest 25% of the jump. Having seen this result, students derive it from the kinematic equations.Again, the idea that the velocity passes through zero at the highest point — obvious from the graph —is important. Students have opportunities to see these ideas work several more times: in analyzing themotion of a football and in analyzing the motion of a cart on a rampwith friction (Fig. 3).

It may seem that students are going over the same concepts rather repetitively. To some extent,they are, but each time the focus is different. First, the primary goals are to become convinced thatthe graphs displayed on the computer screen are representations of the motion in front of the motiondetector, at the same time noticing some general features of the graphs. Later those features are presentagain when the focus is on solving problems or attempting to understand projectile motion. As a result,

7 J. van Aalst.Motion and force, a constructivist approach. Unpublished activity guide, 1994. Available on the internet atwww.sfu.ca/∼vanaalst/physics.html.

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Fig. 3. Graphs of cart moving on inclined ramp, with friction. The cart used to produce this graphhad a friction pad, following a design by Thornton and Sokoloff [27]. Note that the acceleration issmaller when the cart is moving down the ramp.

the key ideas become more firmly established, and students see that the kinematic equations they learndescribeidealizedmotion (they do not describe all features of the graphs). Students can also learn aboutthe value of using models to study a problem with diverse conditions (e.g., different initial velocities,maximum height). An important feature of the sequence is that students must learn toattend to details.Being aware that as one walks faster or slower, the slope of thex–t graph goes up or down, but thatthe slope does notreverse its signunless one actually starts walking in the opposite direction, is farmore informative than “knowing” that “the slope of thex–t graph represents the velocity”. Knowingthat the acceleration of a cart moving (with friction) up a ramp is greater than when moving down theramp adds something important to the idea that the force of (sliding) friction is directed opposite to themotion. Note that this approach also confronts several of the affective problems with traditional physicscourses mentioned earlier in this article: for example, students have greater opportunities to discuss andto celebrate success. (A feature such asv = 0 at the turning point, salient in one activity, is confirmed,but less salient, in another.)

TheWorkshop physics projectandTools for scientific thinkinghave been followed by a numberof projects in which the repertoire of MBL has been extended, including the use of digital video datato analyze two-dimensional motion [29–31]. Two spin-off projects have used activities with MBL inotherwise traditional instruction.RealTime physics, developed by Thornton et al. [32] consists of a setlaboratories fromTools for scientific thinkingand theWorkshop physics project. Unlike in the parentcurricula, the laboratories are independent of each other, and the set has been composed for maximumimpact on conceptual learning, as measured by such questions as are included on the FMCE. In anotherproject, Sokoloff and Thornton have developed a set ofInteractive lecture demonstrations[33]. Here,a small number of lectures are replaced by sessions in which a series of activities from the other MBL

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curricula are done by the lecturer, using the so-called predict-observe-explain format.

3.2. Teacher education projects at the University of Washington

Recognizing the importance of teacher knowledge (subject matter and teaching strategies) the PhysicsEducation Group at the University of Washington has put more emphasis on teacher education thanon the development of complete guided inquiry curricula for students. It has examined students’ con-ceptual knowledge in a wide variety of topics, making explicit what seems to be required for robustunderstanding of the topics. Sometimes the analysis is historical, at other times it makes the logicalrelationships between the ideas clear. Arons has written several books with teaching advice [34] basedon these analyses; such advice can be followed without the use of computers, although the group hasproduced several computer-based strategies. For example, early in the 1980s, Trowbridge and McDer-mott investigated student understanding of velocity and acceleration in one dimension [35, 36]. Oneproblem they noticed was that graphs of motion tended to follow the shape of an incline on which anobject was moving. Based on this research, Trowbridge developed software,Graphs and tracksTM, inwhich students could alter the shape of an incline so that the graphs produced by a ball moving on itwould agree with provided graphs; this software simulated a number of demonstrations and laboratoryactivities Rosenquist and McDermott [37] found effective in addressing the noted conceptual difficul-ties.Graphs and tracksTM was an early example of research-based software without an accompanyingcurriculum. The American Institute of Physics sells such peer reviewed software; many titles are nowavailable.8 The group has developed a guided inquiry curriculum for teachers,Physics by inquiry[38].Because (school) teachers at all levels seem to lack deep knowledge of concepts, this curriculum hasbeen modified to fit the conditions of recital sessions (tutorials) in first-year university courses [39]. Atthe University of Washington, teaching assistants are required to participate in weekly workshops inwhich they work through the tutorials themselves.

3.3. Additional projects

A number of projects have extended many of the ideas that have been discussed above, but they cannotbe discussed in detail here; for a fuller list, see a resource letter on PER by McDermott and Redish[40]; only a few additional efforts are cited here to give some indication of the breath of activity. ThePER web pages mentioned in footnote 1 contain links to most of these projects. At the University ofMaryland, Wittmann et al. [41] have developed tutorials that address a number of conceptual difficultiesstudents have with wave propagation and the superposition of waves, similar to those developed atthe University of Washington. Heller and co-workers at the University of Minnesota have replacedtraditional laboratories with sessions in which students use apparatus to solve context-rich problems[42, 43]. (Context-rich problems require the processing of an extensive set of information; often theproblem itself is not initially well-formulated, but to be articulated by students.) Maloney at IndianaUniversity has developed a number of problem-solving strategies based on research on expertise [44].Halloun and Hestenes [45] then Hestenes [46] have developed a modeling approach, in which studentsbuild models of the physics content to be learned. At Harvard University, Mazur [47] has developedan interactive lecturing style to act on findings of studies on student conceptions in large-enrollmentlectures. He replaces lectures with a series of minilectures, and poses a conceptual question for briefdiscussion at the end of each minilecture. Finally, the CPU (Constructing Physics Understanding)project, co-directed by Goldberg and Bendall [48] at the University of California at San Diego andHeller at the University of Minnesota, like the University of Washington work, is focused on teachereducation, building on research with think-aloud protocols and “benchmark lessons” developed byMinstrell [49]. (The idea of a benchmark lesson is an analogy to the use of benchmarks in surveying;

8 Contact Physics Academic Software, North Carolina State University, Box 8202, Raleigh, NC, 27695, U.S.A.

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it establishes a reference point to which the new material that is to be learned is to be related.)

3.4. Impact on learning and educational research

What is known about the impact of the above curricula on learning? Hake [50] has conducted an analysisof pre- and post-test data obtained with the FCI, the Mechanics Diagnoser, and the MBT from 6500students in 62 courses, using the gain normalized by the maximum possible gain as a metric for “courseeffectiveness in promoting conceptual understanding”. Hake calls this metric the reduced gain,

g = Sf − Si

100− Si

HereSi andSf are the initial and final scores, both expressed as percentages. Hake found that thereduced gains for courses were not correlated with pretest averages, and that classes that used “InteractiveEngagement” methods outperformed traditional classes by almost two standard deviations with respectto the reduced gain.9 Similar effect sizes have been reported for specific curricula in the literature citedearlier [28, 30, 31, 33]. There is also anecdotal evidence that the above curricula positively influencestudent attitudes to physics courses, as well as some evidence that they positively influence enrollmentin upper year science courses.10

Although evidence from pre-and post-test comparisons does not establish acausallink between thecurricula and improved performance on conceptual tests, it is, in my opinion, too substantial to ignore.Greene [51] has pointed out that when Interactive Engagement curricula are used, the instructor oftenstresses that conceptual understanding isimportant, and gives it more weight in evaluation to it than isthe case when traditional curricula are used by posing (some) conceptual questions on exams, and thatthis puts claims about the effectiveness of curricula on the basis of pre- and post-tests into question.But that only illustrates that in research on human subjects an observed effect is usually associatedwith a range of influences that cannot be separated. Thus, while statistical analyses of pre- and post-test data canlend supportto a claim that a curriculum is effective, they are not entirely convincing.11

Consequently, empirical evidence tends to be stronger when a part of an innovation is compared withan alternative to it. For example, an often-cited study by Brassell [52] showed that when the computerdisplay was turned off while a motion was in progress, and turned on at the end of the motion, the impactof Microcomputer Based Laboratory tools was significantly weaker than when the display was onduringthe motion, suggesting that coordination of the physical activity with its graphical representation wasimportant to the observed benefits. Thornton and Sokoloff’s recent work also contrasts the impact ofalternative instructional strategies that have similar goals [14].

In sum, there is considerable support for the curricula from research. From a teacher’s perspective, itis less important which element (e.g., interest, student talk, or instant feedback) contributes most to theobserved impact, as long as the impact is generalizable when these elements are present. However, froma research perspective, the current lack of understanding as to why Interactive Engagement curriculawork is less satisfying. To address this, I suggest that (at least) two types of studies should receive moreattention than they have until now.

9 Hake defines interactive engagement courses as courses designed “at least in part to promote conceptual understandingthrough interactive engagement of students in heads-on (always) and hands-on (usually) which give immediate feedbackthrough discussion with peers and/or instructors” (ref. 50, p. 65).

10 P.W. Laws, in a colloquium given at the Department of Physics, University of Toronto, Toronto, Ont. March, 1999.11 Even where controlled experimentscanbe done, they are often not done for ethical reasons. In research on human subjects,

the interest and welfare of research subject is the overriding consideration, unless a strong argument can be made that thebenefits to the advancement of knowledge and to future student populations outweigh the (short-term) inconvenience or harmto research subjects. On these grounds it could be argued thatwithholdingan educational innovation believed by the instructorto be effective from some students, but not others, is unethical.

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1. Studies that examine the role of conceptual (versus practical) knowledge in problem solvingand in advanced courses for which introductory physics is prerequisite. The contributions suchstudies could make seem to be needed to persuade instructors and students that investing effortin developing conceptual knowledge is worthwhile.

2. “Microanalyses” in which students are observed as they work in natural settings (i.e., as part oftheir regular coursework). Such case studies can document specific events where students beginto use scientific ideas, and then trace if and how the use of such ideas evolves and becomesa stable feature of their thinking. Research of this kind tends to make extensive use of videoanalysis of interactions among students and of how students use materials, and has begun tobecome prominent in educational research on science and mathematics learning in the 1990s.Examples of such studies in high school physics education have been given by Roth and Duit[53] and Roschelle [54].

4. Situating physics education in the larger context of scienceeducation

This section returns to Redish and Steinberg’s claim [1] that PER is an emerging subfield of physicsand outlines a possible change of direction. Redish and Steinberg seem to base their claim on the factthat PER is a practice that has emerged in physics departments. Of course this is true, but I suggest thatinvoking analyses of the history and sociology of science, such as given by Kuhn [55], Latour [56], andothers, leads to a different conclusion. From this perspective, there are several important differencesbetween physics and PER that need to be underscored.

(1) In physics, there is much agreement about the interpretation of concepts. For example, althoughthe concept “electron” may conjure up varying meanings for physicists working in differentsubdisciplines, most physicists would agree that it has mass and charge, and that it is a buildingblock for a number of theories (e.g., of superconductivity and of weak interactions).

(2) Theories built from such concepts have a high degree of predictive and explanatory power.

(3) Physicists are realists. For example, they believe that the notion electron corresponds to a physicalparticle. By comparison, in physics education — and educational research in general — there ismuch less agreement about basic ideas such as “learning”, “concept”, and “mind”; theories haveless predictive and explanatory power; and a realist distinction between a theoretical notion andphysical reality is more contentious.12

To give an example of (2), a popular notion in PER is the “initial knowledge state” [1, 12], an obviousanalogy to similar notions in physics. But although a concept such as “quantum state” is very useful inphysics, the initial knowledge state is less so: little is known about why students come to hold beliefsthat could be described by a given initial knowledge state (i.e., how the initial state could be prepared),it is of limited value to predicting social behavior, and it does not correspond to a configuration ofphysical entities. In sum, my argument is that PER produces knowledge that is qualitatively (especiallyontologically) different from knowledge produced by physics research, and to represent it as a subfieldof physics is, I think, a distortion. Despite these differences, I suggest that PER can (and does) makeprogress toward a more principled approach to teaching and learning physics.

A more important question is why PER should be conducted in physics departments. There are atleast three reasons why it should be.

12 In the study of “emergent phenomena” the commitment to predictability is also contentious, but in this case there is still moreagreement about concepts than in educational research.

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1 It contributes positively to the teaching of physics at all educational levels.

2 The literature on teaching and learning of the last two decades has shown that “top-down” im-plementation of curriculum developed separately from the teaching context in which it is to beused is ineffective; curriculum development must be an activity that invokes both theoretical andpractical knowledge of teaching and learning physics, and the required practical knowledge ismost readily available in physics departments. In university-level physics education, I suggest,the skepticism of educational ideas developed apart from physics teaching contexts has beenmore intense than in schools, in part, because of greater awareness of the state of development ofeducational theory and of the methodological limitations inherent in research on human subjectsthat I have already mentioned.

3 Subject matter knowledge (content and epistemological) is thought to be one of the most importantfactors contributing to the improvement of physics education at all levels. Physics departmentsare in the best position to contribute this knowledge to the educational enterprise. Indeed, currentgraduate programs stress physics content knowledge; the doctoral program in PER at the Univer-sity of Washington, for example, has all the department’s requirements for a doctorate in physics,except that the dissertation researches a PER problem.

To be a sustainableresearch field, however, PER must accomplish more than improve physics educa-tion: it must also contribute to principled understanding of teaching and learning. (Theory developmentis an essential component of research funded by the Social Sciences and Humanities Council, the pri-mary funding agency for educational research in Canada.) Therefore PER must, in my opinion, becomebetter situated in the academic debates about teaching and learning and methods for investigating it. Ithas important contributions to make in this area and should be informed by them. This view requiresthat PER becomes amultidisciplinary field — not based on a smattering of physics and educationknowledge, but on a solid foundation in both disciplines. Before articulating what a graduate programto prepare for that might look like, I describe several specific examples where the relationship of PERto science education research and practice can be strengthened.

4.1. Research methodologyPER has developed several data analysis strategies that could contribute to academic debate aboutquantitative research beyond PER. One example is Hake’s reduced gain [50]. Reduced gains for classes(or class averages) appear to be correlated only weakly with pretest class averages (r = 0.02 for alldata analyzed by Hake, andr = 0.16 for the FMCE), suggesting that the classes that attain the greatestreduced gains are not usually the classes with high pretest averages. This makes reduced gains moresuitable than raw gains for evaluating the effectiveness of educational innovations, but they may stillraise objections for other sources of bias [57]. Further, the psychometric properties of the reduced gainhave so far not been debated adequately; alternative methods based on Analysis of Variance (ANOVA)and regression analysis [58] are available that are better understood in this respect. Of course, debateof these issues may not be of interest to consumers of PER and are better held in journals devoted toresearch methodology. The point is that these developments in PER can contribute to that literature,and that research methodology in PER should be scrutinized as thoroughly as it is in other research onhuman subjects.A similar argument applies to other techniques introduced in PER, such as the treatmentof Likert Scale (continuous disagree-to-agree scales) data by Redish et al. [23].

4.2. MicroanalysesIn research on science education, there has been growth in the number of case studies that documenthow individual students make progress toward coherent, scientific knowledge [53, 54], and how theyare assisted by the cognitive tools (like MBL, graphing, talking, etc.) they have available. Such studies

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would complement the research I have reviewed in this article to develop a fuller picture of learningphysics. In this area, PER may have important contributions to make with respect to how one discussessuch research.13

4.3. Use of physics expertisePER can contribute more to education research by making expertise in physics accessible to theoret-ical and practical projects. There are many opportunities for graduates with extensive subject matterknowledge in physics and analytical skills used in physics. Without going into details, I mention severalefforts in science education and cognitive science in this direction.

• The application of chaos theory and spin systems to cognitive studies of learning [59].

• The application of matrix methods to the analysis of discourse practices in very large bodies of text[60]. (Such bodies of text are produced when students talk about science in computer-supporteddiscussion forums [61].)

• Graduate students and scientists can support science projects in schools by pointing students toresources and helping them develop their ideas [62].

• The provision of ongoing support for teachers in learning more about science and its methods.

To conclude this section, I outline what a graduate program aimed at promoting PER might entail.Bereiter, an educational psychologist at the University of Toronto, writes about two cultures — theprincipled culture of scientific research, and the craft culture of educational practice.14 Progress ineducation depends on the ability of these cultures to learn from each other, that is, on cross-culturaldialogue. Physicists need not become education researchers, nor need education researchers becomephysicists; rather, the educational role of physicists is to teach physics, to reflect on teaching results andto attempt to improve them, and the role of education researchers is to develop systematic understandingof teaching and learning. However,theory and practice must develop togetherin a “dialectical” processin which each is informed by the other.This requires of physics professors that they have some familiaritywith PER, and that they reflect on their teaching and try new strategies and (or) teaching approaches. Inthe last case, it is also desirable that they collect data on their teaching and discuss their experiences withresearchers who collaborate with them. Such activities are new for many physicists, and accommodationsmust be made in faculty evaluations to allow for them.At the same time, this model for PER does requiresome people who can facilitate the cross-cultural dialogue. Rather than having a smattering of physicsand education knowledge, these people must have extensive knowledge in each discipline. A role forPER programs is to train people for this role, and to direct multidisciplinary research programs thatcontribute to education and to improved teaching practice in physics departments. Someone who doesPER would publish both in journals that are likely to be read by physicists (such as this journal) and injournals intended for education researchers (such as the newCanadian Journal of Science, Mathematics,and Technology Educationedited by D. Hodson and G. Hanna). Although this proposal must still beworked out in detail, it might be helpful to imagine what an M.Sc. program in physics education mightconsist of. Following an honors degree (or equivalent) in physics, course work would be divided roughlyequally between physics and education courses — three to four semester courses in each discipline. The

13 For example, there are substantial differences in the amount of detail physicists and education researchers report in researchpapers. Physicists tend toassumefamiliarity with previous work on the problem (which is cited, but not reviewed in detail),as well as that researchers are careful in applying analytical techniques. For example, a physicist might not report the resultsof tests that show that ANOVA techniques can be applied to the data, or the detailed results of tests of differences betweengroup averages.Mentioningthe tests and techniques and reporting effects of theoretical interest is usually sufficient.

14 C. Bereiter. Education in the knowledge age. Book in preparation. A draft version is available atcsile.oise.utoronto.ca//edmind/edmind.html.

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physics courses should have a focus in a field of physics, but their primary purpose is to help studentsdevelop a more advanced understanding of material already introduced at the undergraduate level, notto provide a base forphysics research. The education courses would permit students to become familiarwith previous PER studies, to be introduced to research methodology in education, with the remainderbeing taken from graduate courses intended for education students (depending on interest). The programshould also have at least a short project relevant to education and opportunities for teaching (as graduateteaching assistants). Although this M.Sc. does not fully prepare students fully for research in physics,its graduates could move on to a doctoral program in physics (perhaps with one or two courses extrato the program). Students who do, have a substantially richer preparation for teaching in universitiesand industry. Alternatively, graduates might complete a doctorate in physics education research, withfurther courses in education and physics, or prepare for a career in teaching science in elementary andsecondary schools.

5. Summary

This article has examined physics education research, as practiced in the U.S.A. in the last two decades.The review of PER provided is not exhaustive. For example, it does not discuss any of the course modelsdeveloped from theIntroductory university physics project(IUPP) [63], PER efforts beyond first-yearcourses, or the role of mathematical knowledge in learning physics. Nevertheless, it provides suitablebackground knowledge for discussing what form PER might take in Canadian universities. I discussedthe strengths and weaknesses of PER as based in physics departments, and proposed a multidisciplinaryapproach that retains the current demand for extensive content knowledge in physics, but adds therequirement of putting PER studies in the context of the questions and research methodologies ofeducational research in general. PER can learn from research in other disciplines and, equally important,can make significant contributions to it. Graduate programs in PER, I hope, can also provide a way toattract second-tier students who might be interested in careers in science teaching or education researchto undergraduate and graduate programs in physics departments.

Acknowledgements

The preparation of this article was supported by the Department of Physics at the University of Toronto,where the author was a part-time research associate in 1998–1999. The author would also like to thankJohn Pitre and Tony Key of the University of Toronto and two anonymous reviewers for comments onan earlier draft.

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