Effects of a Laboratory Course on Students ... - ACS Publications

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Chemical Education Research

Diane M. Bunce The Catholic University of America Washington, D.C. 20064

Changing the Laboratory: Effects of a Laboratory Course on Students’ Attitudes and Perceptions

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Melanie M. Cooper* and Timothy S. Kerns Department of Chemistry, Clemson University, Clemson, SC 29634-9703; *[email protected]

Most chemists would agree that the teaching laboratory is a vital component in learning chemistry (1). Unfortunately, and for too long, it has often been used as a place to confirm knowledge students already possess, or to function as a kind of kitchen where students follow recipes with little thought or understanding (2). Educators have grown increasingly concerned that the conventional laboratory format is not accomplishing any useful goal, except perhaps that of training technicians (3, 4). For example, students cannot develop skills such as problem solving, data evaluation and interpretation, experimental design and implementation, and critical thinking in a laboratory where they are required to do little but manual labor (5). A sole emphasis on learning laboratory techniques is appropriate for those who might become laboratory technicians. However, most students will never take another chemistry course, and the laboratory time is better used to instill and practice skills that will have broader applications. As we discover more about how students learn (6), a well-designed laboratory can become a crucial component in the curriculum in which students utilize the higher-order thinking skills that we value. A growing number of alternatives to the conventional verification approach to chemistry laboratories are becoming available, including guided inquiries (7–10), problembased learning (11), metacognitive strategies (12), and learning cycles (13). Over the past decade we have developed a problem-based laboratory format for general chemistry at our university that allows students to work in groups on openended projects (14a). Over the course of the semester, students apply their problem-solving skills to assignments approximating the research process as closely as possible. Students also use written and oral communication skills to plan, critique, and evaluate their experiments. Since these projects generally require much more input, thought, and planning than a conventional laboratory, we employ cooperative learning groups (15) as a support system for conducting the problem-based laboratories. Students make use of the collective wisdom of their group members as they go about the decision-making and design of the laboratory experiments. The effects of these laboratories on students have been very encouraging (16), particularly with regard to increased achievements and retention rates for females. For example, we found that a comparison of mean exam scores for females showed a consistent pattern in which females in cooperative laboratories scored higher on the lecture examinations than their counterparts in conventional laboratories. A statistical analysis of variance (ANOVA) of the scores indicates that the increase in scores for females was significant at a 95% confi-

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dence level. In addition, the retention rate for females in the cooperative laboratories was greater than that of their counterparts in conventional laboratories. The effect for the females in cooperative labs essentially made their performances and retention rates equal to the males in the class, a finding that is still true for our students today. In light of these encouraging results (and considering the fact that we have completely moved away from conventional verification laboratories for over 1600 students per semester without any major problems), the organic laboratories were also redesigned to follow the same kind of open-ended, project-based format as the general chemistry laboratories. Perhaps as a response to calls for change in organic laboratories (17, 18) there is also a growing number of other organic chemistry laboratory programs (19–21) that employ problem-based learning and open-ended tasks. This paper is a report of an investigation into our program specifically, looking at how student attitudes and perceptions are affected by the type of laboratory experience in which they were enrolled. Format of the New Laboratory Course The new organic laboratory format was based on the general chemistry cooperative laboratory course (14), with some changes to take into account the requirements of the laboratory, and the different overall population of students (mostly pre-professional health majors, as opposed to a majority of engineering majors in general chemistry). Students were assigned to groups at the beginning of the first laboratory period. Each student within a group was given a different compound to identify and analyze by the methods available in the lab; some students within the laboratory section had the same compound. The students worked as a group to design their experimental plans, although each person was expected to work individually on his or her own compound. Students were told that others in the laboratory may have the same compound and that these people could serve as a secondary source of information. In this way each student belonged to a long-term cooperative learning group that stayed together the entire semester; each also had an extended group consisting of students who had the same compound to identify or use as starting material. The membership in each extended group changed from project to project. Typically, the projects did not require equipment or instruments different from a conventional lab, and in fact many of the basic “experiments” can be found in more conventional laboratory courses. For example, the nitration of an aromatic

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substrate is a common experiment that can be found in any organic chemistry laboratory manual. In a conventional laboratory experiment students typically nitrate one substrate using a given procedure with a specified reaction time and work-up method. In our labs each member of the group worked with a different substrate, and was required to investigate possible nitration procedures (usually by looking in a range of available laboratory manuals or on the Internet), rather than being given the recipe. After consulting with the instructor each student then nitrated the given compound on a relatively small scale (500 mg), monitoring the progress by thin layer chromatography (TLC). Students discovered that the substrates nitrated at different rates, as seen by the appearance of a new spot and disappearance of the starting material on TLC. They also discovered that some (but not all) of the products were colored, and that some substrates even underwent di-nitration. Some substrates (e.g., acetanilide) required the reaction mixture to be cooled, while some did not yield a product until the mixture was heated. The students also realized that the relative amounts of the nitration mixture (HNO3/H2SO4) were not really crucial since many sources gave different nitration mixtures for the same substrates. Each student then was asked to scale-up the reaction (2 g) and maximize the yield. Some students discovered that activated substituents could decompose if the reaction conditions are not carefully controlled! Reaction products were identified by mp, NMR, and IR spectroscopy. When each member of the group had gathered information on optimum reaction conditions, reaction rates, product appearance, product structure, and yield for the given substrate, these data were pooled and the students in each group were asked to compare and contrast their findings and explain the differences that they found. In this way students were guided to an understanding of activating and deactivating substituents and their directing effects, the effect of conjugation on light absorption, and problems with scaleup. While students may have been explicitly taught about these concepts, they rarely connect them with actual laboratory conditions and results. Pre- and post-laboratory questions were designed to have students reflect upon what they are doing and observing and what these observations mean. The questions were designed to promote the kind of metacognitive activity that has been shown to be so beneficial (12). Additional documents and the instructor’s notes are included in the Supplemental Material.W During the two trial semesters each group completed two projects and the students were assessed based on their written and oral reports, peer evaluations, and instructor evaluation of techniques and attitude. Most of the grade for each student was assigned on an individual basis. That is, students wrote individual laboratory reports, and were assessed individually by the laboratory instructor. The pilot sections of this course were taught by one of us (MMC); subsequently all organic laboratories were moved to this format, which required rather extensive TA training (14b), although many of the TAs were familiar with the overall project-based format as they had already taught in the general chemistry laboratories. Examples of instructor support materials are also available in the Supplemental Material.W

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Assessment Previously, when the cooperative project-based labs were instituted in the general chemistry course, a quantitative assessment was performed using students’ lecture exam scores, retention rates, and attitudes (16). Students were randomly assigned to cooperative or conventional laboratories, and thus a control group of students was available that differed only in lab-type assignment. Students in general chemistry must simultaneously enroll in the laboratory and all must take the same lecture exam. However, organic lecture and laboratory are not required to be taken concurrently, making it much more difficult to establish control groups of students and correlate students’ lecture and laboratory exam scores. We therefore developed a qualitative assessment plan to investigate the effects of the laboratory course on students’ attitudes and perceptions. A qualitative investigation protocol consisting of open-ended surveys, videotaped laboratory sessions, and student interviews was developed (22, 23). Two sections of a pilot laboratory were chosen for investigation: a first-semester laboratory section of 16 students and a second-semester section of 10 students. These students were observed in laboratory and videotaped. In addition, they completed open-ended questionnaire forms and were interviewed about their laboratory experience. The surveys and a description of the interviewees are included in the Supplemental Material.W A total of 10 students, chosen on a random basis, were interviewed by one of the authors (TSK). These students’ responses were compared with responses from students in the conventional laboratory sections scheduled at the same time and conducted in other laboratory rooms, taught by TAs who were known to have obtained good student evaluations in the past. Students in the conventional laboratories completed open-ended surveys but were not interviewed. Students were informed of their rights not to participate, and all of them signed informed consent forms that had been approved by the university’s Institutional Review Board. Almost all the students enrolled in organic chemistry are planning a career in health or veterinary sciences and are highly motivated and competitive. Several of the students were concerned when they discovered that they were in an experimental laboratory section. During subsequent interviews, a few of the students indicated that their experience in the cooperative labs in general chemistry had not been satisfactory. These students felt that they had shouldered the burden of the work in the cooperative labs in general chemistry and others had ridden on their coat-tails (despite the fact that they knew the grading was almost totally individual). Even though some students were somewhat resistant to the cooperative laboratory format, all the originally enrolled students did agree to become part of the pilot program despite being offered places in other conventional labs if they preferred. Student resistance to the cooperative laboratory format was more pronounced with the group of students in the second-semester course. These students had already had one semester of conventional organic laboratory and did not want to change format to a more open-ended and—what they perceived to be—a more demanding laboratory format.


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Field Observations The students were videotaped using two small unobtrusive cameras placed around the laboratory. In addition, a graduate student who was introduced to them as being part of the project observed the students. They acclimated quickly to being observed by both methods and did not seem bothered by either the camera or the graduate student observer. For the first few weeks a typical laboratory began with a few minutes’ introduction from the laboratory instructor, followed by a group discussion. Students then began work— often after further discussion with the laboratory instructor. After several weeks, however, it became apparent that many students came to laboratory and began work without prompting from the instructor. The students became more self-directed and sure of themselves. Students were assigned to a main group for planning and discussion of results, and it was evident that these interactions were quite productive. The laboratory instructor taught each person within a group one or more laboratory techniques, and that person taught the rest of the group and acted as a resource—a variation of the jigsaw cooperative learning technique (24). Each person within a group had the initial task of identifying a different compound, so the experimental procedures and results for each member were not exactly the same. However in the laboratory, there were other students who had the same compound, and students were encouraged to find their counterparts in other groups. In this way the primary group was used for initial planning and support. Then during the actual laboratory work, a secondary group of students made connections as they cross-checked with each other to see whether their compounds did indeed behave in a similar fashion. We saw the development of two types of interactions: (i) those within the main group, where learning and overall synthesis of results occurred, and (ii) those within the secondary group where cross-checking and reinforcement of data and results occurred.

Interviews We interviewed 10 students about their experiences in the new lab format: four from the fall semester and six from the spring semester. Each student understood that they would not be identified. The students were asked questions about science laboratories, science classes, teaching assistants, professors, and the laboratory course they took or were taking. Questions were usually in the form of, “What has been your best laboratory experience? Why?” From responses to these types of questions, questions such as “What did you enjoy the most or least?” were posed. Each interview session lasted approximately 30 minutes and most students were interviewed more than once. In addition to taking notes from the interviews, each interview was recorded on audiotape. Three areas of commonality emerged from these interviews: the nature of the group and how it functioned, the instructor, and the nature of the research and science process itself. Nature of the Groups Since these laboratories are performed by students working in groups, it seems natural that the functioning of the

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group should be a prime concern to the students. “Good” groups were described as those where “everyone pulls his or her own weight and does something”. Another student liked the idea that “everyone was responsible for their own compound, but [they] could still get help from one another”. Other students felt that the groups (used in the organic laboratory) were good because they were “more individualized” and “there was less division of labor” than in the general chemistry laboratories. One student stated, “You had to do your work, because no one else was going to do your reaction for you”. Another said the groups were good because the group provided additional insights and answers that might not have been obvious to him at first. Bad groups were often described as having people who were “slackers” (those who watch while the others do all the work). Some students in this study who had taken the general chemistry laboratory sequence at Clemson said that they felt some of those laboratory groups were bad groups because not everyone did their share of the work. Students generally agreed that the group structure in the cooperative organic labs was better because each student was given a different compound and had to carry out reactions using it, rather than relying on the group effort. As previously stated, organic students are often highly motivated and competitive and may not be typical of the overall student population. These students were strongly affected by the perception (real or imagined) that others were profiting from their work. This laboratory format seemed more acceptable to them since each student was responsible for the identification of his or her own compound, yet students could still rely on both long- and short-term groups for discussion, ideas, and support. The Laboratory Instructor A “good” laboratory instructor was described as one who seemed to care whether or not students learned the information. One student said that a good teaching assistant interacted with students and would give assistance when needed. “They wouldn’t give you the answer, but would lead you in the right direction. Sort of guide you.” Similarly, another said “She would go around and answer questions if we were stuck. But she didn’t necessarily give us the answer...usually pointed us to a resource.” Yet another said he liked that “She was willing to help but didn’t give the answer...if something went wrong, she reinforced what should have happened.” One second-semester student commented that a good teaching assistant “wouldn’t tell us what to do, but would help us out when we got frustrated”. A “bad” teaching assistant was usually described as unhelpful, bossy, or rude. Bad teaching assistants were also described as being bound by the rules. One student described his general chemistry laboratory teaching assistant as being “slack”. “When my laboratory partners weren’t doing anything to help, he wouldn’t get onto them. He also wouldn’t help us if we got stuck. We had to figure everything out for ourselves.” Another mentioned that her roommates had a bad teaching assistant in another organic chemistry section. She said, “They come home very frustrated. The TA doesn’t explain anything; he just gives them the answer. He is also very sarcastic when they ask questions.”


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It is clear from the interviews that the nature of the interaction between the laboratory instructor and the students is critical to the learning environment in the laboratory, a finding that has been discussed by Nakhleh et al. (25). It is also interesting that the students themselves perceive as “bad” both the instructor who provides answers without allowing the student to think, and the instructor who provides no guidance or help. The fine line between providing too many answers and too few answers is critical to the success of laboratory instruction.

The Nature of Science and Scientific Research The third topic that most students brought up in their interviews was the nature of science and scientific research. Many of the students commented that they felt they were doing “real science” or were mimicking “research” because they were not following a set of directions, rather, they were making decisions on their own. One second-semester student said, “It’s sparked my interest in research. I think I’d like to do research fulltime”. Another said, “This lab is more like what I think research is like. I feel like I’m doing real science.” He said, “we have the freedom to experiment…I can make mistakes and not get penalized…that’s so cool.” One second-semester organic student also compared the new cooperative labs with their experiences in the firstsemester conventional laboratory format. “It [CH 227, a conventional format lab] was like we were following a recipe from a cookbook.” This notion of cookbook laboratories came up in several interviews even though such terminology was purposefully avoided in our introductions to the new laboratory format. Another commented, “In my other chem lab, we followed directions from a lab manual written 300 years ago”. Yet another said “[In CH 227] we walked in, listened to the TA mumble about something, we followed what the manual said, and an hour and a half later we were done…it wasn’t useful…I learned some techniques, but not as well as I know them now.”

“freedom to experiment” and that “the student gets to decide the what and how and why of the lab”. One student said he liked “the experimental setup where everyone was responsible for their own reaction and procedure”. A very thought-provoking comment from one student was that he liked being able to make mistakes and to learn from his mistakes. When asked what they disliked, a number of students in the conventional lab format said they thought the labs were too long and they spent too much time waiting for the reactions. One student wrote, “I hardly had a clue of the meaning and I usually just add chemicals like the manual says”. Other students said the lab was “tedious” and “not very instructive”. A common dislike among students in the cooperative laboratory format was that the lab was too long, but most Table 1. Student Responses to the Question: What Do You Like about Organic Lab? Conventional Lab (N = 56)

Project-Based Lab (N = 18)

01. Preparing reactions

01. How the whole class works 000together

02. Cool reactions

02. Personal responsibility

03. Lab atmosphere

03. Individual and group work

04. TA

04. TA

05. Hands-on

05. Hands on experiments

06. Helps understand lecture

06. Student gets to decide

07. Doing labs that relate to 000real life

07. Learned something every lab

08. Straightforward

08. Freedom

09. Students

09. Learning through experiments

10. Nothing

10. Learning by making mistakes

Note: Parts of typical responses are given in order of decreasing frequency where the response appears more than once.

Surveys Open-ended surveys were administered to the 18 students in the new cooperative laboratory sections and to 56 students in conventional laboratory sections that were being taught in other laboratory rooms during the same time slots. Three sets of questions from the surveys were analyzed. One set of questions asked what the student liked and disliked about the laboratory experience. Another set inquired into the students’ perceptions of the roles of the student and laboratory instructor. The last set of questions dealt with the students’ perceptions of skills necessary for success in organic chemistry and in the laboratory. The responses to each question from both formats were compared. Likes and Dislikes When asked what they liked about organic lab, students in both formats of laboratory indicated that there was much to like (Table 1). In the conventional lab format, students tended to focus on two aspects: the teaching assistant and actually doing reactions they had seen before. They appreciated when the teaching assistant was pleasant and answered their questions. Students in the cooperative lab format liked the

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Table 2. Student Responses to the Question: What Is Your Role in Lab? Conventional Lab (N = 56)


1. Learning

1. Figuring out why I’m doing this

2. Watching and learning

2. Completing an experiment with MMmy own understanding of the MMmaterial

3. Listening and learning

3. Understanding the techniques MMused and why they are used

4. Following directions

4. Formulating answers to the MMproblems organic chemistry MMfaces

5. Researching and MMexperimenting

5. Working to understand why MMthings occur as they do



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Table 3. Student Responses to the Question: What Is the Role of the Laboratory Instructor? Conventional Lab (N = 56)


1. Supervising

1. Guiding

2. Leading

2. Helping

3. Guiding

3. Assisting

4. Helping

4. Making me ask questions and learn

5. Making sure we don’t blow MManything up

5. Making it not like a cooking MMclass


Table 4. Student Responses to the Question: What Skills Are Necessary for Success as an Organic Chemist? Conventional Lab (N = 56)


1. Patience

1. Problem-solving abilities

2. Steady hands

2. Imagination

3. Memorization

3. Originality

4. Brains and patience

4. Understanding of concepts

5. Ambition

5. Creativity

6. Precision


students said that they really could not think of anything else they disliked. The Role of Students and Instructors in the Lab When students were asked about their role in laboratory the differences in the typical responses were again striking (Table 2). The students in the conventional style laboratory for the most part had a very passive view of what they were in the lab to do: basically to listen, watch, and learn—quite the antithesis of what we think students are doing in lab! Only one student out of 56 surveyed in the conventional labs said, “to experiment”. Students in the new lab format had a quite different understanding of their role: “to figure out why I’m doing this” “to understand”. In general, they felt that they had a more active role in the laboratory. Similarly, when asked about the role of the laboratory instructor, the differences were again apparent (Table 3). As discussed earlier, many students seem keenly aware that the laboratory instructor is there to assist them when needed, although this idea was less common in the responses from the conventional laboratories. In fact, the most common response from students in the conventional laboratory was that the instructor was there to supervise and lead what occurred in the laboratories. This represents a marked con-

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trast to the prevalent response from the students in the experimental cooperative lab sections who thought that the role of the instructor was to guide rather than lead. Skills Table 4 provides some typical student responses to the question “What skills are necessary to become a successful organic chemist?”. The contrast between the representative student responses from each type of laboratory is again quite striking. Students in the new laboratory format were far more likely to see the creative, imaginative side of organic chemistry. In addition, when they were asked what skills they possessed that would make them successful organic chemists, over 50% of the students from the conventional lab format answered that they had no such skills, while fewer than 25% of the students from the new laboratory format felt similarly. This seems to point to an increase in confidence and empowerment of the students from the cooperative laboratory format, even though some of these individuals had been hesitant and somewhat reluctant at the beginning of the course. Conclusions The format of the organic chemistry laboratory can indeed be changed from one in which students are essentially passive technicians who simply carry out the procedural instructions, to a more interactive and realistic experience. While the nature of the information we obtained from this study is different from that derived from our qualitative study of student achievement in general chemistry laboratories (16), it is no less important. This investigation offers insight into how students perceive the role of the laboratory course, the instructor, and their own role. The feedback we got from the open-ended formats of both the interviews and the questionnaires allowed us to pursue topics that we had not realized were important. The insights we now have can be used to strengthen and improve all our laboratory programs. It was clear that most students understood they could learn valuable skills in a laboratory that would be useful to them later. But it is also clear that the laboratory can be valuable only when taught by an instructor who understands well the purpose of the laboratory experience and when students perceive their role as an active one. The testimony of the students showed us how easily the outcome of a laboratory education can be changed by the environment (groups, instructor, ambience) in which it is structured. For those of us who teach large enrollment courses these insights should come as a reminder that even though we cannot reach out and interact with all our students, we should be very careful about the training and support for those who do interact personally with the students. Acknowledgments We gratefully acknowledge Richard Bauer for his help and suggestions. This work was supported by a grant from the National Science Foundation Division of Undergraduate Education, DUE-9455526.


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Supplemental Material

Supporting documents and notes for instructors, TAs, and students are available in this issue of JCE Online. They include: • A description of the student informants • The survey instrument for students in the conventional lab • The survey instrument for students in the project-based lab • Notes for instructors on conducting project-based laboratories • Handouts for students for the synthesis of antimalarial analogs laboratory • TA notes for the antimalarial analogs laboratory

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9. Birk, J.; Bauer, R.; Sawyer, D. Laboratory Inquiries in Chemistry; Brooks Cole: Pacific Grove, CA, 2001. 10. Rudd, James A., II; Greenbowe, Thomas J.; Hand, Brian M.; Legg, Margaret J. J. Chem. Educ. 2001, 78, 1680. 11. The Power of Problem-Based Learning, a Practical “How To” for Teaching Undergraduate Courses in Any Discipline, Duch, B., Gron, G., Allen, D., Eds.; Stylus Publishing: Sterling, VA, 2001. 12. Rickey, D.; Stacy, A. M. J. Chem. Educ. 2000, 77, 915. 13. Lawson, A. E. Science Teaching and the Development of Thinking, Wadsworth Publishing Company: Belmont, CA, 1995. 14a. (a) Cooper, M. M. Cooperative Chemistry Laboratories, 3rd ed; McGraw Hill: NY, 2005; (b) Cooper, M. M. Cooperative Chemistry Laboratories: Instructor’s Guide, 3rd ed; McGraw Hill: NY, 2005. 15. Johnson, D. W.; Johnson, R.W.; Smith, K. A. Active Learning: Cooperation in the College Classroom; Interaction Book Company: Edina, MN, 1998. 16. Cooper, M. M. J. Chem. Educ 1994, 71, 307. 17. Pickering, M. J. Chem. Educ. 1987, 65, 143–144. 18. Johnson, A. W. J. Chem. Educ. 1990, 67, 299–303. 19. Browne, L. M.; Blackburn, E. V. J. Chem. Educ. 1999, 76, 1104. 20. Hass, M. A. J. Chem. Educ. 2000, 77, 1035. 21. Davis, D. S.; Hargrove, R. J.; Hugdahl, J. D. J. Chem. Educ. 1999, 76, 1127. 22. Phelps, A.J. J. Chem. Educ. 1994, 71, 191. 23. The Ethnographer’s Toolkit, Schensul, J. J., LeCompte, M.D., Eds.; Alta Mira Press: Walnut Creek, CA, 1999. 24. Aronson, E.; Blaney, N.; Stephen, C.; Sikes, J.; Snapp, M. The Jigsaw Classroom; Sage Publications: Beverly Hills, CA, 1978. 25. Herrington, D. G.; Nakhleh, M. B. J. Chem. Educ. 2003, 80, 1197.


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