We used the MPEX survey to probe the distribution and changes in student cognitive attitudes. Based on the results from more than 1500 students from 6 colleges and universities, it is clear that many students come into physics with unfavorable views about the nature of learning physics. Before instruction the students made choices of polarity that concurred with those of our experts only about 60% of the time. More worrisome is that these views tend to deteriorate after a traditional semester of university physics. On the important items measuring independence, coherence and concepts (see Table 1), the starting values were closer to 50%. After one semester of instruction in mechanics, almost no traditional or tutorial classes showed improvement in any of the variables. Indeed, the overall average of 1350 (pre-post matched) students at 3 large research universities deteriorated by about 1 s after one semester of instruction.<h2>Conclusion
However, it does appear that in certain modified learning environments student views do evolve to be more favorable. In the Workshop Physics classes we studied, students showed a 2.5 s improvement on the average of the independence /coherence /concepts clusters. This is displayed in Fig. 5. In this plot, the percentage of students agreeing with the favorable response is plotted on the abscissa, and the percentage giving unfavorable responses is plotted on the ordinate. Since the sum of favorable, unfavorable, and neutral must add up to 100%, the plotted points must lie in the triangle bounded by the points (0,0), (100,0), and (0,100).
Over the past two decades, an increasing number of physicists have been turning their research attention to problems of physics education. About one dozen physics education research programs now exist in research physics departments around the country. One benefit of this is to bring a physicist's perspective and expertise to the study of how to make our physics classes work effectively. A physics department benefits from the development of more effective teaching methods tuned to their particular situation, and by building links to other physics education researchers.
In this article we have discussed the findings of the physics education research community on two of the elements students need to master in order to become expert solvers of complex problems: concepts and appropriate cognitive attitudes. This is by no means the whole story. Additional research is still needed on many topics, including: students' ability to apply concepts in problems, their reasoning and use of mathematics, and the impact of technological environments on what students learn. But the by-now large **** of physics education research (reference 2 cites more than 200 items) has provided many solid and surprising insights that can help physics instructors improve their judgments about what is happening in their own classrooms. This research has led to a variety of curricular tools and techniques that can help instructors deliver more effective instruction (see reference 16). But what is perhaps most important is that the dialog within the physics community on what is effective in instruction is now well begun. We have started the process of growing, evaluating, and cumulating a solid set of community knowledge on what works ó and what it means for instruction to work.
We would like to thank all of the members of the Physics Education Research Group at the University of Maryland for their contributions to the research described in this paper. This paper benefited from the useful comments from the members of the physics education research groups at the Universities of Maryland and Washington. Support by the NSF and the Fund for the Improvement of Post secondary Education is gratefully acknowledged.
Sidebar 1: Students misinterpret representations.
What was Dirk really thinking about light after successfully completing introductory calculus-based physics? In order to find out, I showed Dirk a small bulb, a piece of cardboard with a rectangle cut out, and a sheet of paper. 9 "What would you see on the paper if the room light were turned off and the little bulb on?" (I never did the experiment, I just asked what if.) Dirk drew a picture of perpendicular sine curves and called one the "electric flux" and the other the "magnetic part." A strange approach given that the problem can be easily solved with a ray diagram. "So what would you see on the screen?" Dirk eventually drew straight lines and came up with the correct response. "What if the slit were narrower?" Dirk said that geometrical optics applies as long as the slit is wider than the wavelength of light because "the waves are still making it through the slit." Not only is this answer incorrect, but this is an unusual way to describe light. "What if the width of the slit were a little bit less than the wavelength of the light?" Dirk stated that now a diffraction pattern occurs; the magnetic part of the wave will not "be affected" but the electric part "will be affected Ö [the slit] knocks it out of whack." Dirk explained how the amplitude of the electric wave hits the sides of the slit causing the diffraction, but the magnetic part of the wave gets through because it is lined up with the long dimension of the slit.
We interviewed 48 students who had finished introductory calculus-based physics. Most were among the best in the class. During each interview the goal was to probe what the student was thinking while trying not to affect what s/he was thinking. Students were asked to make predictions and explain their reasoning. In accounting for their predictions, about half of the students had some sort of spatial interpretation of the amplitude of light. The figures show two examples. Most of the other students did not do as well as these two.
This type of research has guided the development of tutorials . 10 For physical optics, students supplement the standard mathematically oriented textbook / lecture by making observations of water waves propagating freely and through slits of various widths, applying principles of superposition when there is more than one wave present, and building an analogy with the behavior of light. Students build an understanding of the different models they are using, and consider both the values and limitations of the models. There is an emphasis on reasoning required for the development and application of important concepts and principles.
In some lecture classes at the University of Maryland, tutorials have replaced the traditional quantitative recitation sections. Not surprisingly, we found that tutorial students did better on conceptual / qualitative questions. However, we also found that tutorial students also did considerably better on a standard textbook like problem (60% vs. 16% correct). 9 R. N. Steinberg
Sidebar 2: Students hold contradictory views at the same time.
In one of my engineering physics classes, I gave this question on Newton's third law from the Force Concept Inventory 11 on the final exam. One of my better students came to my office after the exam and was very upset. She expressed her confusion about which of two colliding vehicles felt the greater force, a small car, or a large truck and reported that she had changed her answer numerous times during the exam. "I know," she said, "that Newton's third law says they should be equal, but that can't be right, can it?" The classroom context led her to bring up her "physics class" model, Newton's third law, but the common-speech wording of the question led her to bring up her common sense response, larger objects exert a larger force. Successfully learning Newton's third law was not enough for her to be comfortable with the situations in which it should be used.
When this problem was given to large numbers of Maryland students as a pretest, only 30% chose the correct answer, (E), with 66% of them choosing answer (A). After recitations, the number of correct answers rose, but only to 50% with half of the students still giving answer (A). After tutorials, the number of correct answers rose to 80% with only 20% choosing answer (A). (N = 238 for recitations, N = 529 for tutorials.) E. F. Redish
- J. Rigden, "The emergence of the technical workplace," The Changing Role of Physics Departments in Modern Universities , edited by E. F. Redish and J. S. Rigden, AIP Conf. Proc. 399 (American Institute of Physics, Woodbury NY, 1997), pp. 133-138.; R.C. Hilborn, "Revitalizing undergraduate physics - Who needs it?" Am. J. Phys. 65 , 175-178 (1997).
- For a comprehensive overview and set of references, see L.C. McDermott and E.F. Redish, "Resource Letter on Physics Education Research," to appear in American Journal of Physics .
- L. C. McDermott and P. S. Shaffer, "Research as a guide for curriculum development: An example from introductory electricity. Part I: Investigation of student understanding," Am. J. Phys. 60 , 994-1003 (1992); erratum, ibid. 61 , 81 (1993); P. S. Shaffer and L. C. McDermott, "Research as a guide for curriculum development: An example from introductory electricity. Part II: Design of instructional strategies," Am. J. Phys. 60 , 1003-1013 (1992).
- R. N. Steinberg and M. S. Sabella, "Performance on multiple-choice diagnostics and complementary exam problems," Phys. Teach. 35 , 150-155 (1997); T. O'Brien Pride, S. Vokos and L. C. McDermott, "The challenge of matching learning assessments to teaching goals: An example from the work-energy and impulse-momentum theorems," Am. J. Phys. 66 , 147-156 (1998).
- R. Czujko, "The Physics Bachelors as a Passport to the Workplace:Recent Research Results," AIP Conf. Proc. 399 , 213-223 (1997).
- F. Reif, "Scientific approaches to science education," Phys. Today 39 (11), 48-54 (1986); An extensive review of the problem-solving literature can be found in "Research on Problem Solving: Physics," David P. Maloney, in Handbook of Research on Science Teaching and Learning , edited by D. Gabel, (MacMillan Publishing Company, New York NY, 1993) 327-354.
- J. H. Larkin and F. Reif, "Understanding and teaching problem solving in physics," Eur. J. Sci. Educ. 1 (2), 191-203 (1979).
- L. C. McDermott, "Research on conceptual understanding in mechanics," Phys. Today 37 (7), 24-32 (1984); L. C. McDermott, "Millikan Lecture 1990: What we teach and what is learned ó Closing the gap," Am. J. Phys . 59 , 301-315 (1991).
- B.S. Ambrose, P.S. Shaffer, R.N. Steinberg, and L.C. McDermott, "An investigation of student understanding of single-slit diffraction and double-slit interference," to be published.
- Tutorials in introductory physics , L.C. McDermott, P.S. Shaffer, and the Physics Education Group at the University of Washington (Prentice Hall, New York NY, 1998).
- D. Hestenes, M. Wells, and G. Swackhammer, "Force concept inventory," Phys. Teach. 30 , 141-158 (1992).
- E.F. Redish, J.M. Saul, and R.N. Steinberg, "On the effectiveness of active-engagement microcomputer-based laboratories," Am. J. Phys. 65 45-54 (1997); J. M. Saul, "Beyond problem solving: Evaluating introductory physics courses through the hidden curriculum," Ph.D. Dissertation, University of Maryland (1998).
- D. Hammer, "Epistemological beliefs in introductory physics," Cognition and Instruction 12 (2), 151-183 (1984).
- E.F. Redish, J.M. Saul, and R.N. Steinberg, "Student Expectations in introductory physics," Am. J. Phys. 66 212-224 (1998).
- E. F. Redish, "The implications of cognitive studies for teaching physics," Am. J. Phys . 62 , 796 (1994).
- The Changing Role of Physics Departments in Modern Universities, edited by E. F. Redish and J. S. Rigden, AIP Conf. Proc. 399 (American Institute of Physics, Woodbury NY, 1997), Vol 2.
- See ref. 10 and L. C. McDermott, P. S. Shaffer, and M. D. Somers, "Research as a guide for teaching introductory mechanics: An illustration in the context of the Atwood's machine," Am. J. Phys . 62 , 46-55 (1994).
- P. Laws, Workshop Physics Activity Guide (John Wiley and Sons, NY 1997); P. Laws, "Calculus-based physics without lectures," Phys. Today 44 (12), 24-31 (1991).
- R.R. Hake, "Interactive-engagement versus traditional methods: A six-thousand-student survey of mechanics test data for introductory physics courses," Am. J. Phys. 66 , 64-74 (1998).