The Influence of Model Kits on Spatial Ability in Organic Chemistry

Transcription

1 The Influence of Model Kits on Spatial Ability in Organic Chemistry Jonathan Greer Raybin and Adam Walter Lee Dec. 15, 2010 Abstract When learning organic chemistry, students are required to study the structure, properties and reaction of organic compounds. The study of one such property of organic molecules, chirality, requires students to identify elements of symmetry in the organic molecule, a practice greatly aided with molecular model kits. This research investigated whether the use of molecular model kits aided the ability of students to answer spatially challenging questions, using a survey to assess spatial aptitude and test organic chemistry ability. The data indicated average improvements of 16 percent with the use of model kits. Furthermore, this benefit was largely confined to students with initially low spatial ability, who improved by an average of 26 percent. These findings demonstrate the value of visualization tools and methods in understanding organic chemistry. 1

2 The Influence of Model Kits on Spatial Ability in Organic Chemistry Multiple Intelligence theory has long modeled student learning by dividing it into a range of distinct domains. These include linguistic, logical, spatial, kinesthetic, musical, interpersonal, and intrapersonal learning styles. Different subjects and teaching styles each target different aspects of this educational spectrum. 1 In particular, organic chemistry intrinsically requires highlevel spatial reasoning skills. This follows because an understanding of chemical structure is integral to broader aspects of the course and is greatly influenced by a student s spatial ability. 2 Chemical modeling kits are therefore frequently used as a visualization tool for understanding the 3-dimensional conformations of molecules. In particular, this physical representation should benefit students with poorer intrinsic spatial ability. This inspires our research question of their overall effectiveness in teaching: ow does the use of chemical modeling kits influence students ability in organic chemistry? We hypothesize that, while model kits will provide benefit across the board, they should have a greater impact on those with lower spatial ability. Further understanding of these effects will enable development of improved ways to cater to individual learning styles and benefit the overall educational process. Methodology A sample of 28 students across 6 workshops was measured. Between workshops, students were separated into two groups one allowed to use model kits and the other forbidden and asked to complete a brief questionnaire. The survey, appended to this report, included a quantitative self-assessment test to determine spatial learning ability, inspired by the Jefferson 2

3 County Multiple Intelligences Teacher Inventory. 3 This data, on a 35 point scale, was used to divide students into categories of high ( 27 points), average (23-26 points) and low ( 22 points) spatial ability. The survey was followed by three organic chemistry questions (Figure 1) designed to test spatial reasoning skills, selected from workshop #6 of the Chemistry 203 Workshop Manual. Answers were graded on a binary scale with a maximum score of 3 points. Our analysis examined how access to model kits influenced the scores of each spatial ability group. Results and Discussion Organic chemistry is considered a challenging subject for students for a variety of reasons. In part, this reputation is justified by the demanding requirements of the class. To perform well, students must learn to build their knowledge base into a high-level conceptual understanding. Unfortunately, it can be difficult to motivate students, especially within an anonymous lecture hall environment. Devising methods for simplifying this learning process is therefore highly desirable for educators. abraken argues that emphasizing the spatial components of chemistry, along with extensive use of visualization aids, could improve accessibility to the field. The true nature of chemistry can be realized only when the importance of visual-spatial thinking in chemistry is acknowledged. 4 In 2001, a survey of 276 organic chemistry students by Dori and Barak found that the use of physical and computer based models benefitted students relative to a control group. Furthermore, this study examined how these effects varied with respect to overall academic performance. In the final analysis, that research determined that the use of chemical modeling helped narrow the gap between low and high level students, in addition to improving scores 3

4 across the board. 1 Our proposal seeks to elaborate on these findings by more specifically targeting students spatial learning ability. Because modeling kits primarily serve as a visualization aid, we suspect that they predominantly benefit students with lower innate spatial aptitude. The selected questions tested students ability to determine a molecule s chirality, a topic heavily emphasized in previous workshops. Characterization of a compound as chiral or achiral requires the ability to properly identify symmetry elements. These exercises can be performed through mental visualization or using pencil and paper, but they are greatly facilitated through the 3-dimensional structure of model kits. Furthermore, model kits offer an excellent opportunity to check work; achiral molecules can be superimposed onto their mirror images. Decide whether each of the three compounds shown below is achiral or chiral. Solutions O O O O Achiral (Inversion Center) 3 CC 2 3 C Br Br Achiral C 3 C 3 3 C C 3 3 C C 3 Chiral (Enantiomers) Figure 1: The selected questions emphasized understanding of stereochemistry. 4

5 Scores on this quiz varied across the scale and were evaluated against a range of factors. First, several baseline tests were taken to assess the validity of our initial assumptions. We had anticipated that students with higher spatial ability would perform better than those with lower ability, independent of model kit access. Our data aligned with each of these expectations. On average, students with improved spatial reasoning performed approximately 10 percent better at determining chirality than students with lower ability (Figure 2). If these results had conflicted with our predictions, it would have indicated a problem in our methodology. On the contrary, they support our premises, and indicate that the self-assessment test is a reasonable measure of spatial aptitude. 100% 80% Low Spatial Average Spatial igh Spatial 60% 40% Mean Median Mode 20% 0% Figure 2: Effect of spatial reasoning ability on scores. Next, we compared the relative performance of students of students with and without the use of model kits. ere, access to model kits produced even more significant improvement of 16 percent (Figure 2). Additionally, most students reported that they found model kits useful on exams. These findings support the idea that model kits provide a valuable service, and their use should continue to emphasized in class and within workshops. 5

6 100% 80% No Models Models 60% 40% Mean Median Mode 20% 0% Figure 3: Effect of model kits on scores. Groups with access to model kits performed significantly better than those without. The improvement gined from using model kits was largely concentrated among student with lower spatial ability (Figure 4). Indeed those with higher ability actually had lower scores (by 33 percent) when using model kits. Meanwhile, the scores of students with lower ability improved by 26 percent. These results correspond well with the findings of Dori and Barak. 1 owever, the steep drop in scores among students of higher spatial ability is troublesome. ow could the use of additional tools have possibly decreased overall performance? We posit that these higher-level students may have rushed through questions more quickly and oversimplified their answers. Still, these findings are indicative of our small sample size and other sources of potential experimental error. 6

7 100% 80% igh Spatial No Models Low Spatial Models 60% 40% Models No Models Mean Median Mode 20% 0% Figure 3: Use of model kits predominantly favored students with low spatial ability. Strangely, student with high spatial ability performed worse with model kits. Several sources of error may have complicated these results. One concern is that students rushed through the problems without putting real effort into the work; in the provided comments section, one student even noted that she used shotgun answers, not analyzed in depth. Another likely source of error emerges from the small sample size. The overall number of data points tested was diminished further when the groups were divided into smaller and smaller categories. For example, only 6 students placed into the high spatial ability category. Still, these initial results hint at promising trends. A continued analysis of this research question should use a broader sample size and provide incentive for students to perform to their best ability. Conclusion and Future Work In the final analysis, this data supports the idea that model kits aid visualization for certain organic chemistry problems. Using model kits improved overall performance, particularly among students with lower ability to start. Consequently, we conclude that the use of modeling kits should continue to be encouraged and supported in organic chemistry. 7

8 These initial results provide a strong incentive to continue further investigations. To improve upon these findings, future studies should work with larger sample sizes. Additionally, some incentive should be provided to ensure that students are working to the best of their ability, perhaps by analyzing actual exam results. Continued investigation of this research question should seek to better pinpoint learning styles that most benefit students. References 1 Snyder, R. F. (2000). The Relationship between Learning Styes/Multiple Intelligences and Academic Achievement of igh School Students. The igh School Journal. 83(2), Dori, J.Y. & Barak, M. (2001). Virtual and Physical Molecular Modeling: Fostering Model Perception and Spatial Understanding. Educational Technology & Society, 4(1). Retrieved from 3 Jefferson County Multiple Intelligences Teacher Inventory, 3 abraken, C.L. (1996). Perceptions of Chemistry: Why is the Common Perception of Chemistry, the Most Visual of Sciences, So Distorted? Journal of Science Education and Technology, 5,

9 Spatial Reasoning Survey Preliminary Questions 1) ow useful do you find your model kit during exams? (1 is least useful; 5 most useful) 2) ow frequently do you use model kits in Workshop or outside of class? (1 is least useful; 5 most useful) 3) ow would you rate your ability to visualize chemical or other spatial systems? Spatial Reasoning Survey Directions: For each statement choose the appropriate answer. Please make your choices quickly. There are no right or wrong answers, so make the choices that describe you best. Rarely Occasionally Sometimes Usually Always 1. When I close my eyes I see clear visual images. 2. Using maps is easy for me Color coding helps me learn things I enjoy visual puzzles such as mazes, jigsaw puzzles, 3-D images. 5. I navigate well in unfamiliar places I often draw or doodle Geometry was easier than algebra Chemistry 9

10 Decide whether each of the three compounds shown below is achiral or chiral. These questions are for research purposes only. Answer to the best of your ability. Ch 2 Ch 3 C 3 O O Br C 3 C 3 Final Questions 1) Were you allowed access to your model kit for this survey? Yes No 2) ow useful did you find your model kit for this survey? Did not Use (1 is least useful; 5 most useful) 3) Comments? 10