Department of Physics, Högskolan Dalarna, S-78188 Borlänge, Sweden
New permanent address: ITN, Campus Norrköping, Linköping University, S-60174 Norrköping, Sweden.
Note submitted to the Physics Teacher
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In a recent paper in this journal Francis et al1 discuss the important question of whether instructional strategies that purport to achieve high gains on conceptual test such as the Force Concept Inventory (FCI)2 produce a permanent change in students' world view from "Aristotelian" to "Newtonian", or whether the effects reported in a number of studies3 are only temporary. This question is highly relevant since conceptual tests are traditionally administered as pre-test at the beginning of a course and as post-tests at the end. With a test immediately following instruction the possibility that the effects reported are temporary cannot be ignored.
The study of Francis et al was conducted at Montana State University in the context of an algebra-based introductory physics course. At Montana State, course reform began in 1992 and the traditional labs were replaced by the research-based Tutorials in Introductory Physics4. In 1996, the average pre-test score on the FCI was 27% and the average post-test score was 67%, corresponding to a normalized gain5 of 55%. Students from the fall classes of 1996, 1995 and 1994 were asked to participate in a "follow-up test" which took place 1 - 3 year respectively after their initial post-testing. In their study, Francis et al compared the follow-up test and the post-test averages on FCI (matched sample) of the participating students. They saw only a very small decline over the several years following instruction. Thus they concluded that their reformed course achieved a long-term fundamental shift in students' conceptual framework.
At Högskolan Dalarna in Sweden some initial reform in our introductory mechanics teaching started in the 1995/96 academic year, when microcomputer based labs (MBL) using PASCO-equipment were introduced. In later years more MBL-based labs were introduced. From the 1997/98 academic year, support from the Swedish National Agency for Higher Education, Council for Renewal of Undergraduate Education, was obtained. The instructional approach used by us can best be described as an adaptation of the ideas behind the RealTime Physics6 approach to a Swedish educational setting, with instructional material written in Swedish by the author. This approach was used in a mechanics course (Mechanics I) taken mainly by civil engineering students and in a physics course taken mainly by pre-service teachers. The pre-service teachers who studied physics in 1995/96 used preliminary versions of a subset of the labs later used in the Mechanics I course. For example no labs investigating Newton's 3rd law were included in the 1995/96 lab-curricula. Other labs were improved in later implementations of the lab-curricula in mechanics.
The preservice teachers studied physics and physics education as a single subject in their second semester of studies and took a Mechanics and Heat course as the first physics course during this semester. They had studied mathematics and mathematics education in their first semester. These students studied to became mathematics and science teachers with certification for teaching in grade 4 - 9 in the Swedish compulsory school. The civil engineering students studied their Mechanics I course during the 3rd quarter of their first year. They had taken a course in one-variable calculus and a course in linear algebra and two other courses during their first semester. Concurrently with the mechanics course they took a course in transform-methods and differential equations. Both the preservice teachers and the civil engineering students were required to have studied mathematics and physics in all three years in the science or the engineering specialisation of the Swedish upper secondary school ("Gymnasium") or the equivalent in adult education or in a science prepatory year. The mathematics curricula in the upper secondary school included some calculus and some linear algebra and the physics curricula is partly calculus based. Both groups were also required to have completed the two year chemistry course in "gymnasium" and the pre-service teachers were required to have completed the two year biology course. Admission to the civil engineering program was lowly selective in 1997/98 and all qualified students were admitted to the pre-service teacher program in 1995/96.
Fig 1. Results of pre- and posttesting of student conceptual understanding of Mechanics using the Force and Motion Conceptual Evaluation7. Data is included from the following groups:
Mechanics I: Students who took the Mechanics I course spring semester 1998.
Preservice Teachers: Test taken at the beginning of autumn semester 1998 by 7:th semester preservice teachers who studied physics spring semester 1996 in their second semester. These students took a subset of the labs (preliminary versions) used in Mechanics I.
Traditional: Test taken at the beginning of fall semester 1998 at Högskolan Dalarna by students who have had taken different traditionally taught engineering mechanics courses.
| Course | Pretest Average | Posttest Average | Gain (G) | Normalized gain (g) |
|
Preservice teachers 1995/96 |
~50% | 71% | ||
| Mechanics I 97/98 | 51% | 73% | 22% | 45% |
| Traditional 97/98 | ~50% | 58% |
Table 1. Results from pre- and posttesting using Force Concept Inventory done 1998. Matched sample for Mechanics I. The pretest averages for Preservice teachers and Traditional are an educated guess inferred from pretest data taken by similar groups.
As part of the assessment of the curricular reform in mechanics the preservice teachers, who studied physics in 1995/96, were asked to take the Force Concept Inventory (FCI)2 and the Force and Motion Conceptual Evaluation (FMCE)7 conceptual mechanics tests in the middle of the fall semester 1998, 5 semesters after they had studied mechanics. These students had not studied any more physics since 1995/96, but had studied courses in chemistry, biology and education and had done some practice teaching. About half of the original group participated in this "follow"-test. No matching with pre-test data was possible since this group had not taken any pretest. The results of the posttesting are displayed in figure 1 and table 1. The preservice teachers, who were tested 5 semesters after their physics course, did almost as well as the students in the reformed Mechanics I course, who were tested at the end of their course. However they displayed poorer understanding of Newton's 3rd law and of "coin acceleration". These differences between the groups are consistent with changes in the lab curriculum between the present Mechanics I course and the early version studied by the preservice teachers. Ron Thornton has developed a method8 for the investigation of different more or less coherent views held by students from their answers to the different questions in the FMCE-test. According to his analysis, students can, for example, believe in a "physicists' view" of Newton's 2nd law for decreasing velocity but not at the same time hold a "physicists' view" for increasing velocity. In figure 2 are displayed the fraction of students from different courses holding a "physicists' view". The preservice teachers show a higher fraction of "physicists' views" in all areas and thus have a more coherent view, in this conceptual area, than the Mechanics I students. This could be due to the fact that the preservice teachers had been practicing teaching and thus may have been "forced" to think through their own views.
Fig 2. Percentage of students holding a "Physicists' view". Students views are assigned from FMCE-data using the conceptual dynamics method developed by R Thornton8.
Francis and coworkers1 conclude that their "data strongly support the claim that some forms of instruction (but not necessarily all) do achieve fundamental shifts in students' conceptual frameworks". Francis et al implemented a tutorial approach4 and we implemented a modified RealTime Physics6 approach. These curricula both try to address students' misconceptions and to actively engage the students' minds. Our data, and the data of Francis et al implies that curricula that actively engage the students do appear to make a permanent change in their conceptual framework.
Acknowledgment
Partial financial support from the Swedish National Agency for Higher Education, Council for Renewal of Undergraduate Education, is gratefully acknowledged. Karin Bernhard is acknowledged for technical assistance, Edward (Joe) Redish and David Hammer for valuable discussions and Dennis Kuhl for valuable assistance and advice regarding the FMCE-test and the "Conceptual Dynamics" model match.
References
1. G Francis, J Adams and E Noonan, "Do They Stay Fixed?", Phys. Teach. 36, 488-490 (1998).
2. D Hestenes, M Wells and G Swackhamer "Force Concept Inventory" Phys Teach 30, 159-165 (1992). The FCI-test translated was into Swedish by J Bernhard 1997.
3. See for example R Hake "Interactive-engagement vs traditional methods: A six-thousand-student survey of mechanics test data for introductory physics courses", Am J Physics 66, 64 - 74 (1997)
4. L McDermott Tutorials in Introductory Physics (Prentice-Hall, 1998). L McDermott, S Vokos and P Shaffer "Sample Class on Tutorials in Introductory Physics" in Redish E and Rigden J (Eds), AIP Conference Proceedings, 399, 1007 - 1018. New York, American Institute of Physics, 1997.
5. Normalized gain, g, is defined as
g = (%posttest average - %pretest average)/(100 - %pretest average)
6. D Sokoloff, R Thornton and P Laws. RealTime Physics, active learning laboratories. Wiley, New York, NY, USA (1998). P Laws "A New order for Mechanics" Proc Conf on Intro Physics Course, 125 - 136, Wiley, New York, 1997.
7. R Thornton and D Sokoloff "Assessing student learning of Newton's laws, The Force and Motion Conceptual Evaluation and the evaluation of active learning laboratory and lecture curricula". Am J Phys, 66, 338 - 352 (1998). The FMCE-test was translated into Swedish by J Bernhard 1998.
8. R Thornton "Conceptuals Dynamics: Following Changing Student Views of Force and Motion" in E Redish and J Rigden (Eds), AIP Conference Proceedings, 399, 913 - 934. New York, American Institute of Physics, 1997.