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Student Active Learning Methods in Physical Chemistry Robert J. Hinde and Jeffrey Kovac* Department of Chemistry, University of Tennessee, Knoxville, TN 37996-1600; *[email protected]

A major focus of recent curriculum reform efforts in chemistry has been the introduction of student active learning methods into undergraduate courses (1). In this paper we describe our recent efforts to introduce active learning into physical chemistry (2). During the spring semester of 1999 we both taught courses in physical chemistry. RJH taught the second semester of the mainline physical chemistry course for majors while JK offered the second semester of the biophysical chemistry course taken primarily by biochemistry majors. The principal topics of both courses were quantum mechanics and spectroscopy. We employed quite different strategies, however. RJH supplemented the traditional lecture method with cooperative-learning sessions that explored selected topics in more depth. These heavily computer-based sessions were held approximately once every two weeks in the chemistry department computer lab. JK used cooperative learning almost exclusively, supplementing it with occasional mini-lectures. JK’s students used a preliminary version of a set of guidedinquiry materials being developed at Franklin and Marshall College by J. N. Spencer, R. S. Moog, and J. J. Farrell, which rely almost exclusively on “pencil-and-paper” calculations. This paper describes the two approaches in detail and then compares and contrasts their relative strengths and weaknesses. Since the two courses represent the two extremes of strategies for incorporating active-learning methods, we hope that this comparison will be useful to faculty considering the adoption of such methods. Overall, we found that the use of active-learning methods was beneficial to both students and faculty. Not only did students seem to learn the material more thoroughly, they also had a more positive attitude about the subject at the end of the semester. Our experiences and conclusions are consistent with those of other faculty in chemistry and other fields who have used various active-learning approaches. Extensive research has shown that cooperative learning is a very effective pedagogical technique (3). Not only does cooperative learning facilitate a deeper understanding of the course material, it also develops important learning process skills (4 ). Overall, active and cooperative-learning methods seem to provide a richer and more satisfying learning environment (5). Course Details: Physical Chemistry for Majors (Chemistry 483) Chemistry 483 is the second half of a two-semester physical chemistry sequence populated by chemistry majors and chemical engineers. In the spring of 1999, 27 students were enrolled. Approximately one-third of these students were chemistry majors; the others were primarily chemical engineering majors. Three graduate students in chemistry also enrolled in the course to satisfy entrance deficiencies. This enrollment is typical. Chemistry 483 is traditionally a lecturebased course with three 50-minute sessions each week. The content is that of a typical majors’ physical chemistry course using a standard textbook such as Physical Chemistry by R. A. Alberty and R. J. Silbey.

Approximately one lecture period every other week (typically alternate Fridays) was converted into a cooperative guided-inquiry workshop. These workshops were heavily computer based, involving spreadsheet calculations, graphical analysis of data, elementary computer algebra using Maple (Maple is a registered trademark of Waterloo Maple, Inc.), and some custom-designed Web-based simulation packages constructed for the course. Seven workshops, which are listed in Box 1, took place over the course of the semester in the department computer laboratory. These computer-based workshops were designed to be an integral part of the course and provided a convenient opportunity for cooperative guided-inquiry activity. However, there is no logical connection between computer-based learning and cooperative learning; the Chemistry 481 class described below employed cooperativelearning techniques without computers, and the computerbased guided-inquiry workshops used in Chemistry 483 could be used by individual students. Groups of three or four students worked cooperatively on these exercises in the computer laboratory. These groups were established by RJH at the beginning of the semester and remained fixed during the course. The three graduate students were placed into one group; seven other groups, each with at least one chemistry major and one chemical engineering major, were formed from the remaining 24 students. Mixed groups of chemistry majors and chemical engineering majors were created as part of a conscious attempt to diversify the groups. Each team of students submitted a single set of “answers” or “results” for every active-learning exercise, which were returned with comments and corrections. These teams of students also worked together on weekly homework assignments. Each group turned in one set of homework solutions and received a common grade for the homework assignment. To minimize competition, final course grades were computed according to a predetermined absolute point scale. Homework assignments accounted for 45% of a student’s final grade, weekly in-class 15-minute quizzes accounted for 25%, and a comprehensive two-hour final exam accounted for 20%. The remaining 10% of a student’s final grade came from attending the active-learning exercises. Each student who was present in the computer laboratory for one of the seven activelearning exercises earned a point toward her or his total activelearning grade, regardless of whether the student’s team finished the workshop “correctly”. Students who attended all seven Box 1. Topics of Active-Learning Exercises in Chemistry 483 Wave–particle duality and the photoelectron effect Boltzmann probabilities and the microcanonical partition function Probability density and the Born interpretation of the wave function Heisenberg’s uncertainty principle The variational principle The secular determinant Molecular orbitals of H2 and H2+

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NOTE: A detailed description of each exercise can be downloaded from http://rhodium.chem.utk.edu/~chem483/S99/handouts.html.

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exercises received full credit for the 10% active-learning portion of the final course grade; students who skipped one or more active-learning exercises earned proportionally less. Students were not assigned roles within their teams. In many teams, these roles seemed to emerge gradually over the course of the semester; often one student was designated as “the Maple person”, another student operated the Web-based simulations, and a third recorded the team’s answers. Once established, these roles seemed to be in effect for the remainder of the semester. During the active-learning workshops, RJH and a fourth-year graduate student in physical chemistry roamed around the computer laboratory, acting as “consultants” for teams that had questions and trying to “jump-start” teams that seemed to be stuck. Course Details: Biophysical Chemistry (Chemistry 481) The entire course was conducted using a cooperativelearning format supplemented by “just-in-time” mini-lectures. The students were given primary responsibility for the course. Decisions concerning due dates, weighting of the various parts of the course in the final grade, kinds of exams, and other course matters were made by the students on the basis of suggestions by the instructor. The students were asked to perform both a midterm and a final assessment of the course and a midterm and final assessment of the cooperative-learning process. Changes in the course were made on the basis of the midterm assessment, and verbal suggestions were always considered. As evidenced by all their formal written assessments of the course and by their active participation in discussions and decisions about requirements and grading, the students felt that they had primary responsibility for their own learning. The course met for 50 minutes three times per week. There were 27 students registered for credit and one auditor, a graduate student in electrical engineering who attended essentially all the class sessions and worked through the course material. A majority of students were biochemistry or biology majors; only five considered themselves chemistry majors. (At the University of Tennessee, Knoxville, the biochemistry major is a concentration in the Department of Biochemistry, Cell and Molecular Biology.) There was one graduate student from Biomedical Sciences registered for credit. Most of the students indicated that they intended to pursue careers in the health sciences: medicine, dentistry, pharmacy, and veterinary medicine. A few were interested in secondary education, and a few were planning to attend graduate school in some field related to chemistry or molecular biology. Students were asked to purchase the Franklin and Marshall guided-inquiry materials from a local copy shop. The required textbook, which had been chosen by another instructor for the first semester of the course, was not very useful as a resource for the Franklin and Marshall materials so a few key references were photocopied and distributed to students as needed. In addition, a supplementary book on mathematics was recommended. Class sessions were primarily devoted to cooperative learning using a method described below. JK and a graduate teaching assistant from Biochemistry moved around the classroom working with individual groups as necessary. A few short lectures were given at various points in the course and time was set aside for questions from the class as a whole. Some homework problems were assigned during the semester 94

Box 2. Sample Summary Assignment from Chemistry 481 In no more than 2 pages summarize what you have learned about molecular vibrations (harmonic oscillator problem) and rotations (particle on a sphere). In your summary you should include at least the following points. 1. The physical model 2. The development of the appropriate Schrödinger equation for the model, beginning with the classical energy. Be sure to discuss the approximations and assumptions that are made in the development of the mathematical formulation. 3. The nature of the wave functions and the energy levels 4. The predicted spectrum

and students were given the option of working the problems in groups or individually. Three times during the term the students were asked to write two-page summaries of the material they had processed during the previous few weeks. A sample summary assignment can be found in Box 2. These summaries were graded holistically on a scale of 1 (low) to 6 (high) on the basis of both content and form (6 ). The students were divided into cooperative-learning groups of three or four. The groups were self-selected and remained constant throughout the semester. There were eight groups: four groups of four and four groups of three. At the beginning of the semester the students were provided with guidelines concerning cooperative learning that identified specific roles such as manager and recorder. The use of roles was not enforced, however, and most of the groups seemed to find their own style of working, with natural roles developing. In retrospect, stricter role definition and regular rotation of those roles might have improved the group performance. Of the eight groups, six functioned very well. Two groups, one with four members and one with three members, functioned less well primarily owing to frequent absences by group members. This required some rearrangement of groups on a day-to-day basis. Although the students tried to adapt, each group took on its own personality, making it difficult to bring new members into the culture for a day. Two take-home examinations were given during the semester. The final examination was also given on a take-home basis. A five-page term paper was assigned. Since the primary objective of the term-paper assignment was to have students write coherent scientific prose, they were given considerable freedom in the choice of topics—as can be seen in the formal assignment, which can be found in Box 3 along with a summary of the complete course evaluation scheme. The students were expected to submit a rough draft and revise that draft on the basis of comments from JK. The final drafts were graded holistically using the 1–6 scale. Overall, the term papers were quite well written. Finally, students were evaluated based on their in-class performance as members of their cooperative-learning group. The form used for this evaluation, which was discussed and approved by the students, can be found in Box 4. Students were asked to assess their own performance on a scale of 1 (low) to 5 (high) and to list their strengths and areas for improvement as members of a learning team. They were also asked to rate the other members of their group similarly. Using these evaluations and his own observations, JK assigned each student a grade for in-class performance on the same

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Box 3. Evaluation and Grading for Chemistry 481 Activities and weights 1. 2. 3. 4. 5. 6.

In-class group work 10% Homework problems 9% Written summaries of course material 9% Take-home exams (2) 36% Paper 16% Final take-home exam 20%

Details 1. Group work will be evaluated by a self and group assessment scheme. At the end of the semester, you will be asked to evaluate all the other members of your group and yourself on a numerical scale and to make confidential comments. I will use these evaluations along with my observations to assign a grade for in-class performance. You will have the opportunity to comment on and approve the rating scheme. 2. Homework problems will be assigned and graded on a regular basis. 3. Several more one-page summaries will be assigned during the semester. These will be evaluated holistically using a 1 (low) to 6 (high) grading scale. 4. Two take-home exams will be given during the term. 5. Paper. You may choose one of the following three options. Topics must be approved by the instructor. a. Historical paper on a scientist or a discovery b. Explanation of an important concept to be covered in the course c. Summary and critique of a scientific paper that involves one or more of the important concepts in the course. 6. Final take-home exam. The final exam will be comprehensive.

Box 4. Form for Evaluation of Group Work in Chemistry 481 Name: _____________________ Please rate your own performance this semester on a scale of 1 (low) to 5 (high) based on the following criteria. 1. 2. 3. 4. 5.

Attendance Preparation Your contribution to the group learning process Your own mastery of the course material Development in learning and thinking skills

Your rating should take all five factors into consideration. Numerical Rating for yourself: ______ List your three most important strengths as a member of your group. List three areas in which you feel you need improvement. What are your most important insights on the cooperative learning process that we have used in this course? Please rate the other members of your group based on the criteria listed above. In addition, please comment on what you feel were the most important strengths of each member and the areas in which they need improvement. Name: __________________________ Strengths: Areas for improvement:

Rating: ______

Box 5. Chemistry 483 Student Survey Results

Statement

% Agreeing

The active learning exercises helped me learn the course material. 92 I would like to have more active learning exercises and fewer lectures. 54 If I could choose between Chemistry 483 with active learning exercises and Chemistry 483 without active learning exercises, 100 I would choose the course with active learning exercises. It was useful to work on the homework assignments as a group. 62 My group worked well together on the homework assignments. 38 It was useful to work on the active learning exercises as a group. 100 My group worked well together on the active learning exercises. 54

scale. Final grades for the course were assigned according to the guidelines outlined in Box 3. Assessment Methods: Physical Chemistry for Majors Approximately one week before the final exam, the students completed an anonymous written questionnaire during class time (with RJH absent from the classroom). This questionnaire was a standard one, adapted with permission from the University of Washington, that all University of Tennessee instructors must administer as part of a mandated campus-wide course evaluation program. A supplementary sheet is provided with this questionnaire on which students may make open-ended comments; however, only the numerical portion of the questionnaire is actually processed by the University’s course evaluation office. The open-ended comments are passed on to the instructor in the students’ own handwriting, without transcription, after final grades have been submitted. The standard questionnaire did not address the activelearning aspects of the course directly. However, a number of students mentioned the active-learning exercises positively in their open-ended comments. Some of these comments are: I appreciated the active learning exercises as I find it easier to learn new material if I actually do something with it. Active learning sessions were useful—helped clarify material. Active learning assignments helped me to understand and apply what [was] taught in class.

These comments suggest that several students found a “handson” guided-inquiry approach helpful in learning physical chemistry and in developing mental constructs that integrated the course material into a coherent “package”. No students offered negative comments about the activelearning workshops. However, one student remarked that more time should be devoted to the workshops. Most groups failed to finish a workshop within the 50-minute class period and were permitted to “regroup” outside of class to finish the workshop before the next lecture period. RJH bears some responsibility for the inability of most groups to finish the workshop within the allotted time, because the workshops were fairly ambitious. In addition, the class meeting time was at 8:00 A .M., and although students were fairly punctual on “lecture days”, many students straggled in five or ten minutes late on “workshop days”, preventing their group from making full use of the 50-minute period. Because the standard course evaluation questionnaire did not directly address the course’s cooperative-learning aspects, the students were also asked to fill out an anonymous Webbased evaluation form during finals week. Thirteen students (four chemistry majors and nine chemical engineering majors) completed this questionnaire, which asked them to indicate their level of agreement with several statements on a 5-point scale (strongly agree, agree, neutral, disagree, or strongly disagree). Box 5 lists some of these statements and the fraction of respondents who agreed or strongly agreed with each statement. The results shown confirm that some students find a guidedinquiry approach helpful in learning physical chemistry. The Web-based questionnaire also asked for open-ended comments about aspects of the course most and least liked. Here, students again praised the guided-inquiry workshops. A number of students expressed displeasure with the function-

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ing of their homework teams outside of class. They resented the fact that not all members of a team participated equally on homework assignments, and felt unable to force their colleagues to “step up” and contribute to these assignments. Assessment Methods: Biophysical Chemistry Students were asked to provide anonymous written assessments twice: about a month into the course and at the end of the semester. The assessment asked them to identify the strengths and areas for improvement in the course and to comment on the performance of the instructor. In the final assessment they were also asked to describe their personal insights into learning that had been gained during the course. JK read the midterm assessments carefully, summarized the results, and responded to the comments and suggestions. This written summary and response was distributed to the class and discussed. As a result, a number of changes were made in the course. A time was set aside at the beginning of each class session for public “consulting questions” and more minilectures were given to provide students with a broader perspective on the course material. Students were also asked to do a “team reflection” after about four weeks of group work. The questions used in this process can be found in Box 6. The students found the team reflection valuable because it forced them to look at how the groups were functioning and to reflect on their personal responsibility for the learning process. Instructor’s Assessment: Physical Chemistry for Majors These are the first-person reflections of RJH concerning his course. I found the active-learning exercises enjoyable; I felt more “connected” to the students and I felt that I had a better idea of what individual students did and did not understand about the topics treated in the active-learning workshops. I was somewhat disappointed, however, that the time invested in these cooperative guided-inquiry sessions did not improve student performance in the course as reflected in the final grades. I compared the final grades earned by students in spring 1999 with those earned by students in spring 1997 and fall 1997, which were the two most recent times I taught Chemistry 483. I aggregated the students from calendar year 1997 into one group containing 29 students to facilitate comparison with the spring 1999 group. The same absolute grade scale was used during all three semesters, and the weekly quizzes and final exams were very similar for the three classes. The distribution of final grades for spring 1999 did not differ significantly from the distributions observed in calendar year 1997. Box 6. Team Reflection Assessment Questions for Chemistry 481 What are the two most important ideas concerning molecular vibrations that you learned in this activity (ChemActivity 5)? What is the most important unanswered question that you have about molecular vibrations? What are the two greatest strengths of your team? What are two ways in which your team can improve its performance? What is your most important insight about learning?

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This observation is in accord with the findings of Dougherty et al., who studied the effects of cooperative learning on final exam grades and final course grades in three introductory chemistry classes (7). Dougherty et al. found that students enrolled in a class that employed cooperative learning and students enrolled in a control class with no cooperative-learning techniques obtained very similar scores on a set of common final exam questions. Low-performing students in the spring 1999 class did not appear to be concentrated in certain groups; instead, the teams of students often included one student with a final grade of A and another student with a final grade of C or D. Why did the guided-inquiry workshops, which the students generally found valuable, not materially affect student performance as measured by final course grades? At least three explanations are plausible. First, I may have (unconsciously) tailored the activelearning exercises to challenge the best-performing students. While these students may have found the exercises valuable, they also may have been more likely to earn a high final grade whether or not I used guided-inquiry techniques. The workshops may have been designed at a level that was too advanced to benefit the lower-performing students. Second, it is possible that the lower-performing students did not participate actively in the cooperative guided-inquiry workshops and therefore did not benefit significantly from them. I noticed that several lower-performing students adopted a team role in which they recorded the observations made and conclusions drawn by their more active colleagues, who actually operated the computer. Finally, there may have been a certain level of “disconnect” between the material covered in the guided-inquiry workshops and group homework assignments and that covered on the weekly quizzes and final exam. (The quiz and exam scores, because they vary from one student to the next, are the dominant factors that differentiate between A–B and C–D students in a single group.) The time constraints placed on the in-class quizzes and final exam forced me to ask less sophisticated questions on the quizzes and exam; these questions largely focused on solving numerical problems. Apparently the highly conceptual focus of the guided-inquiry workshops did not help prepare lower-performing students to solve these problems. Although I tried to strike a happy medium between conceptual questions and numerical problems on the weekly group homework assignments, it is difficult to determine whether students actually worked on these assignments as a group. Possibly the lower-performing students had a tendency to “freeload” off of other group members while working homework problems; this hypothesis is supported by students’ complaints about the performance of their homework groups. No clear solution to this problem is apparent. Instructor’s Assessment: Biophysical Chemistry These are the first-person reflections of JK concerning his course. Overall, the students were quite positive about the cooperative-learning format of the course. On both the midterm and final assessment they commented that they had learned a lot from the course, probably more than in a lecture course. They appreciated the relaxed, informal atmosphere of the class and the student-directed pace of the course. They also liked the fact that they were asked to take responsibility for their

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own learning. Being responsible to the other members of their group helped them learn the importance of coming to class properly prepared. Finally, they found that teams have greater emotional resiliency than individuals. Their groups helped them learn sophisticated material and solve difficult problems. They also pointed to a number of improvements that might be made. One of the weaknesses of the Franklin and Marshall guided inquiry materials is that they do not provide the “big picture”. Many students commented that they would have liked more lectures to provide them with a broader perspective on the detailed work they were doing in their groups. While most students appreciated the self-paced nature of the course, Box 7. Selected Student Comments from the Final Assessment of Chemistry 481

These comments are taken verbatim from the final assessments. In a few cases grammatical and spelling errors have been corrected. Strengths of the Course High quality learning of the material. (Cooperative learning leads to a greater understanding of material through not only verbalizing your thoughts but viewing the problem through someone else’s perspective.) The flexibility of the course. Being able to slow down in certain sections to really grasp the material has been very helpful. The group work was wonderful. Everyone had different capabilities so we were able to piece them all together. Responsibility: by not having the class in lecture format pointed out clearly what our responsibilities were. Having a support system (team) greatly facilitated my learning and understanding of the materials. Groups provide support when failure occurs—harder to give up The summary assignments were very valuable for understanding the material. Greater satisfaction when material is mastered successfully.

Suggested Improvements These comments are synthesized from the various suggestions made by the students. Require that some of the assignments be turned in. A good textbook and other resource materials were needed. More lectures to wrap up and clarify ideas and give the “big picture.” Provide answers to the questions and problems in the workbook or have the instructor regularly review the student answers to provide feedback. More all-class discussion.

Insights about learning Cooperative learning teams increase levels of understanding of material. Peers make material seem more conquerable. When you realize that your peers are really just like you, you become less focused on how you’re doing in comparison to them and can just jump right into learning. (Standards become more toward bettering yourself not your standing within the class.) Learning is best done “hands-on.” That is, more information is actually absorbed this way. The interactive learning-teaching (your colleagues) also helps the process. The above is also aided by the written summaries. That synergism is possible through cooperation. Mathematical concepts do actually make things intelligible. Science is actually not so bad. The pressure to pull your own weight in the groups helps to motivate myself to work harder and not slack off! Learning is more successful if the students have input in what they think their assignments and deadlines should be. Material learned in the past and deemed useless at the time can actually be helpful in the process. In cooperative learning one learns as much socially, it could be argued, as academic knowledge. This is very important for developing life skills. A supportive environment can be conducive to learning. Learning should be fun.

the more compulsive among them were uncomfortable without a schedule. Since the evaluation methods were developed as the course proceeded, the more grade-conscious students were nervous about where they stood. Another problem was that the textbook for the course was not a good resource for the guided-inquiry materials. Although I provided handouts and suggestions of resources, the students had to take responsibility for finding books to supplement the in-class learning. While finding resources is an important skill, having a good textbook would have made their lives easier. Selected student comments from the final course assessment can be found in Box 7. Judging from their performance on the exams, the students learned a lot about quantum mechanics and spectroscopy. They demonstrated both conceptual understanding and problem-solving ability. Perhaps more important, they learned a number of intellectual process skills—particularly teamwork, but also critical thinking and problem-solving skills. Several students commented that the summary assignments were especially valuable and had taught them an important learning tool. Finally, they learned the importance of regular self-assessment. I learned that it is very difficult to facilitate a course that uses cooperative learning as its primary pedagogical technique. In an informal atmosphere it is hard to keep the tension at the right level, pushing students to process the material efficiently while giving them enough time to learn. Since students have other courses, they do not always prepare properly, but it is essential to find ways to ensure that they do prepare. In a lecture course student absences have only a minor effect on the conduct of the course; in a cooperative-learning course, students must be present or the process can break down. The instructor must be prepared to handle these situations or the students will suffer. Both preparation and attendance were considered in the final evaluation of in-class performance, but after-the-fact evaluation is not very effective in changing behavior. I suspect that keeping attendance and giving regular short quizzes would have been more effective. On the other hand, a cooperative-learning environment can be much more enjoyable for both students and instructor. As an instructor you have a good idea of what every student does and does not understand. You can individualize your teaching, responding to individual and group needs. Discussion The student response to our attempts to introduce active learning into physical chemistry has been positive. Overall, students felt that the active-learning sessions were valuable learning experiences. Perhaps even more important, they felt more positive about physical chemistry. As instructors, both of us enjoyed using active learning because it connected us more closely with our students and their learning. We learned a lot from reflecting on our initial experiments and will try to enumerate these lessons. While a number of faculty have been successful in teaching general chemistry using only a guided-inquiry cooperativelearning approach (8), it appears that it is much more difficult to teach physical chemistry in this way. It is very difficult for students to extract the “big picture” from guided-inquiry exercises, so regular lectures or high-quality reading materials are needed to provide this perspective. The proper balance between exposition and guided inquiry will depend on the

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students. In retrospect, however, the students in biophysical chemistry would have benefitted from more lectures, and the students in physical chemistry for majors would have benefitted from more active-learning exercises. This conclusion is strongly supported by the work of R. M. Felder, who has studied the importance of learning styles in science and engineering education (9). Felder points out that students come to our courses with a variety of learning styles, so a single pedagogical technique will not reach all of them (10). The guided-inquiry cooperative-learning approach favors students who prefer inductive, local, and active approaches. Other students, however, prefer deductive, global, and passive approaches. While the techniques used in Chemistry 481 were quite varied, the lack of a good textbook and the dearth of lectures disadvantaged global and deductive learners. While Chemistry 483 provided excellent lectures, the small number of cooperative-learning exercises disadvantaged those students who prefer active and inductive methods. Felder’s papers provide excellent advice on strategies to teach to a broad variety of learning styles. Extensive use of active learning places considerable demands on both faculty and students. As noted above, it is very difficult to establish the correct level of tension to keep students moving yet give them sufficient time to process the course material. In a lecture course the instructor sets the pace and students must struggle to keep up. If students are allowed to set the pace, it will be slow enough to accommodate the pressures of their other courses. In a cooperative-learning situation, where the instructor interacts informally with students and gets to know them well, it is psychologically difficult to push hard; you are painfully aware of the difficulties every student is having in understanding the material. Finding the balance of compassion and toughness is difficult. Student absences are a serious problem for a course that makes extensive use of cooperative learning. Both the student and the cooperative group suffer. In Chemistry 481 two of the eight groups were seriously hurt by frequent absences of one or more group members. The absence problem was less serious in Chemistry 483 only because there were fewer cooperative-learning sessions. Narrative comments indicate that most students in Chemistry 481 felt an obligation to come to class regularly and to come prepared. In fact, a number of groups met outside of class to work together on various assignments. Unfortunately, a few students were less responsible. Neither peer pressure nor the prospect of a poorer final grade seemed to make a difference. This is an important question: designing appropriate incentives and penalties to make sure that all students attend class regularly. In both courses we had the advantage of having graduate teaching assistants to help us with implementing the activelearning approach. Neither had any previous training or experience with this pedagogical approach so they had to learn new teaching techniques as the semester progressed. Although both of them did a fine job, this points to the importance of proper selection and training of teaching assistants for courses that use active-learning methods. On the basis of our experiences and conversations with colleagues who use cooperative learning, we feel that it is important for students to have assigned roles and to rotate those roles regularly (11). The roles help groups function more efficiently and help ensure that all students in the group ben98

efit from the process. In both classes we observed that some students were able to sit back and take advantage of the other group members. Positive interdependence is a crucial element of successful cooperative learning and it is important to use techniques such as assigned roles and regular team reflection to build the spirit of interdependence (5). In Chemistry 481 we found that having to write regular summaries is a powerful learning tool for students. These summaries forced students to reflect on what they had learned and organize the discrete lessons into a coherent whole. This technique should be equally applicable in a lecture course. Students do need to be guided in constructing their summaries and their work should be carefully evaluated (6 ). Another challenge is making sure that the examinations properly reflect the course content presented through active learning. As Sheila Tobias has recently pointed out, examinations are the hidden curriculum (12). In Chemistry 483, RJH chose to give traditional in-class quizzes featuring types of problems which were quite different from those that the students were asked to solve in the computer-based activelearning sessions. While the in-class quizzes ensure individual accountability, they may not accurately test what the students learned in the active-learning exercises. In Chemistry 481, the students voted for a take-home final exam, which allowed JK to ask them to solve more complicated problems but also allowed the students to collaborate outside of class, thus weakening individual accountability. At a college or university with a well-functioning honor code, it is possible to give take-home examinations that hold students individually accountable, but in our context this is impossible. Finding creative ways to test the skills and knowledge attained through active learning, while still maintaining individual accountability, is a challenge for the future. Perhaps the biggest advantage of active-learning methods is that they encourage students to take control of their own learning; the course belongs to the students and not only to the instructor. The course atmosphere is more relaxed and conducive to learning. In both courses, most of the students came away with a positive impression of physical chemistry, which is a success in itself. Acknowledgments We are grateful to Richard S. Moog, John J. Farrell, and James N. Spencer of Franklin and Marshall College for allowing us to use the preliminary version of their guided inquiry materials. RJH thanks B. K. Taylor for his assistance in administering the computer-based active-learning exercises in Chemistry 483. Literature Cited 1. For example: Wright, J. C. J. Chem. Educ. 1996, 73, 827. Spencer, J. N. J. Chem. Educ. 1999, 76, 566. Farrell, J. J.; Moog, R. S.; Spencer, J. N. J. Chem. Educ. 1999, 76, 570. Hanson, D. M.; Wolfskill, T. J. Chem. Educ. 1998, 75, 143. Kovac, J. J. Chem. Educ. 1999, 76, 120. 2. For a similar perspective on the use of active learning in physical chemistry see Zielinski, T. J. The Mastery Learning Alternative to Physical Chemistry Lecture; http://www.monmouth.edu/ ~tzielins/dpapers/essay2.htm (accessed Jul 2000). 3. A useful bibliography can be found in Nurrenbern, S. C.; Robinson, W. R. J. Chem. Educ. 1997, 74, 623.

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Research: Science and Education 4. Duncan-Hewitt, W.; Mount, D. L.; Apple, D. A Handbook on Cooperative Learning, 2nd ed.; Pacific Crest: Corvallis, OR, 1995. 5. Johnson, D. W.; Johnson, R. T.; Smith, K. A. Active Learning: Cooperation in the College Classroom; Interaction Book Co.: Edina, MN, 1991. 6. Kovac, J.; Sherwood, D. W. Writing Across the Chemistry Curriculum: An Instructor’s Handbook; Prentice Hall: Upper Saddle River, NJ, 2000. 7. Dougherty, R. C.; Bowen, C. W.; Berger, T.; Rees, W.; Mellon, E. K.; Pulliam, E. J. Chem. Educ. 1995, 72, 793. 8. Farrell, J. J.; Moog, R. S.; Spencer, J. N. J. Chem. Educ. 1999, 76, 570.

9. Felder, R. M. J. Coll. Sci. Teach. 1993, 23 (5), 286; J. Chem. Educ. 1996, 73, 832. 10. Excellent introductions to learning styles can be found in Sternberg, R. J. Thinking Styles; Cambridge University Press: Cambridge, 1997 and Sarasin, L. C. Learning Style Perspectives: Impact in the Classroom; Atwood: Madison, 1998. 11. Hanson, D. M. An Instructor’s Guide to Process Workshops; Department of Chemistry, SUNY Stony Brook: Stony Brook, NY, 1996. 12. Tobias. S.; Raphael, J. The Hidden Curriculum: Faculty-Made Tests in Science; Plenum: New York, 1997.

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