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Project Background PHY 100 is an introductory level physical science survey course designed for non-science majors to satisfy the University's general education science requirements. A small fraction of students entering the course had a rich science background in high school (this become apparent very early on) and most have limited competency beyond basic college-level algebra. Within this context, at an HBCU, I have attempted to merge my own research interests in visualization for science education with an investigation of the effects of a systematic approach to teaching students how to decode visualizations. As a survey course, PHY 100 covers some physics, chemistry, earth science and space science - all areas rich with discipline-specific scientific visualizations. Several visualizations appear in each textbook chapter - a resource most students have invested in, so I chose those particular objects to be part of my instructional focus. Part of the promise of using visualizations is to give students another formal representation scheme for the mental models (either structural or process) of physical phenomena that they have built. The visual representation would coexist with verbal, numerical, graphical and symbolic schemes that students might use to help them make sense of the world around them.
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The Literature There is considerable evidence in the literature documenting students' difficulties with proportional reasoning (McDermott et. al. 1996) and persistent misconceptions with the concepts of velocity and acceleration (e.g. Camp & Clement 1994). From my own teaching experience I also had a wealth of information regarding PHY 100 students' models of the solar system (Chaudhury, 1999). Thus, I felt reasonably confident that I had a baseline of evidence on students' demonstrated knowledge to compare with the additional findings of this project.
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Bibliography Camp, C. W., & Clement, J. J. (1994). Preconceptions in Mechanics: Lessons Dealing with Students Conceptual Difficulties. Dubuque, IA: Kendall/Hunt. Chaudhury, S. Raj (1999). The Science Studio : Student learning in an introductory physical science course. AAPT Summer Meeting, San Antonio. McDermott, L (1996). Physics By Inquiry. John Wiley & Sons, New York. Lawson. A.E. (1978). The development and validation of a classroom test of formal reasoning. Journal of Research in Science Teaching, 15, 11-24. Lawson, A. E. (1987). Classroom Test of Scientific Reasoning: Revised Paper and Pencil Version. Tempe: Arizona State University. Tobin, R. & Capie (1984). The test of logical thinking. Journal of Science and Mathematics Teaching in Southeast Asia. 7. 1, 5-9. Wollman, W. and Karplus R. (1974). Intellectual Development Beyond Elementary School V: Using Ration in Differing Tasks. School Science & Mathematics, Vol. 74, pp. 593-613
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Free Fall This segment of the project focused on student learning of 'free-fall' as demonstrated in their ability to answer questions about the baseball player throwing a ball into the air which then eventually falls back down. An alternate title for this section would be : "Decoding and deconstructing a diagram of free-fall : understanding students' approaches to the interpretation of visual clues about physical and mathematical phenomena". The 'deconstructed' images are available in the Resource Bin - labeled according to their demonstration of Position, Velocity or Acceleration of the ball as a function of time. Details of the results of video interviews and written tests are provided in the Evidence section.
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Proportional Reasoning This valuable ability, especially necessary for quantitative comparisons across the sciences, can be a substantial barrier for student learning in physical science. On a pair of very similar tasks there was a strong correlation between the performance of students on the 'verbal' task and their performance on a 'visual' task. Students who were successful with the verbal task (essentially a word problem) were almost invariably able to succeed on the visual task but the converse was not true. The experiment was repeated with a different section of PHY 100 (w/different instructor) and student profiles were remarkably consistent. Further details on the tasks and the results are provided in the January snapshot, the final report and the resource bin.
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Solar System Structure This aspect of the project was concerned with student generated visualizations (diagrams) of the structure of the solar system. Pre-instruction versions of these diagrams have been collected for several years and consistently show students choosing an orbital model. Students have various degrees of accuracy with regards to location, relative distance and even number of planets etc. in the solar system. As part of this project three visualizations of the solar system from the textbook were emphasized during the instructional phase. Post-instruction diagrams by students showed alternate, yet valid ways to represent the solar system structure, though the traditional orbital model still held sway with the majority. The figure shows a student drawing of solar system structure showing relative MASSES of planets and Sun. Not seen previously without visualization-focussed instruction.
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Methods This project used a mix of qualitative and quantitative methods. 1. Free-fall : A cluster of questions about the "Up & Down" diagram were created by the instructor. These were administered in a section of PHY 100 that I taught in Fall '03, in other sections taught in Fall '03 and Spring '04 and finally used for 'think-aloud' video interviews with volunteer students. Numerical results were compiled from the test data and are available in the Resource Bin. Numerical data on student answer distributions as well as transcripts were coded from the digital video of student interviews. 2. Solar System : student generated visualizations were classified into (i) traditional (ii) alternate (iii) misconception. Up to two errors in planet locations were ignored. 3. Proportional reasoning task : student written responses to visual and verbal tasks were hand-coded by instructor and an assistant. Of 9 visual tasks, a score of 7 or higher was deemed competent. On the verbal task, students were scored on a 0 (none correct), 2 (one part correct) or 4 (both parts correct) scale.
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Evidence 1. Free-fall : (i) Students who had direct instruction on the Up & Down diagram performed considerably better on test items than other PHY 100 students who had 'covered' the material in class but without explicit attention to the visualization details. This seems to indicate that the 'decoding' aspect can be taught, even to non-science majors. (ii) However, video interviews revealed that science majors enrolled in a more sophisticated physics course, who had no prior exposure to the particular diagram performed considerably better on the same set of questions - with no particular pattern to their utilization of the diagram in answering the questions. (iii) PHY 100 students across different semesters and different instructors show the same pattern of difficulty with fundamental, concepts. Video interviews revealed that in a small set of cases, students verbalized the correct response but nevertheless chose an incorrect multiple-choice answer. 2. Proportional Reasoning: (i) Students who performed successfully on the verbal task ('word problem') were ALL successful on the paired visual reasoning task, however the converse was not true. This result held true for students in two different semesters with two different instructors.(ii) Student performance on the cluster of 'Up & Down' diagram questions also directly correlated with their performance on the visual/verbal task pair - i.e. students with high scores on the verbal proportional reasoning task scored 20% higher average than those who failed the verbal task. (iii) A small sample of science majors completed both visual and verbal tasks with ease. 3. Solar System : (i) Student generated visualizations of the structure of the solar system revealed that a majority (56%) still chose the traditional orbital model (ii) Two alternate views - one based on relative masses and one based on relative angle of the ecliptic plane emerged as the choice of approximately 20% students (iii) Standard misconceptions still persisted with the remainder (24%) of the students.
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Conclusions Scientific visualizations have the potential for an important role in the teaching and learning process for non-science majors. The evidence collected in this project indicates that visualizations can (i) help students with conceptual clarification of fundamental phenomena (ii) promote alternate, valid views of physical structures that depart from the traditional (iii) provide a mechanism for demonstrating reasoning abilities where conventional textual representations are a barrier. The video interviews did reveal different ways novice students talk about physical phenomena - some depend on recall, some bring forth various combinations of relevant technical terms on appropriate prompts (such as 'anything that is scientific about this diagram) and yet others are able to notice surface features of a diagram but not connect these with actual conceptual explanations.
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