Article pubs.acs.org/jchemeduc
A General Chemistry Laboratory Course Designed for Student Discussion Carrie A. Obenland, Kristi Kincaid, and John S. Hutchinson* Department of Chemistry, Rice University, Houston, Texas 77063, United States S Supporting Information *
ABSTRACT: We report a study of the general chemistry laboratory course at one university over four years. We found that when taught as a traditional laboratory course, lab experiences do not encourage students to deepen their understanding of chemical concepts. Although the lab instructor emphasized that the lab experiences were designed to enhance understanding of chemistry, both survey and interview data show that students instead feel that the lab is primarily useful in learning laboratory procedures. As a result of these studies, the laboratory course was reconfigured to include weekly, separately scheduled times for teaching assistant-moderated student discussion of concepts, analysis of data, and reflection on the laboratory. With the inclusion of required discussion, students did report that the lab was a place for learning chemistry and visualizing the chemical phenomena discussed in class. KEYWORDS: First-Year Undergraduate/General Chemistry, Laboratory Instruction, Collaborative/Cooperative Learning
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aboratory work is a nearly universal component of the Introductory or General Chemistry curriculum at the college level. The reasons for this universal inclusion are many, but in general they stem from the view that Chemistry is an experimental subject and that therefore experimentation should be part of an introduction to Chemistry. Despite the multiplicity of goals for requiring laboratory work of introductory students, scant evidence exists to demonstrate that these goals are actually met for these students.1 In this paper, we analyze data regarding student motivations in the laboratory as well as their achievement of instructors’ goals, and we present one model implemented and tested for restructuring the laboratory to improve the achievement of the instructors’ goals.
4. To give students some insight into basic scientific laboratory methods, to let them use their hands, and to train them in the use of these methods. The goals and purposes of those early laboratories diverged as the field of chemistry grew,4 however in recent history these goals have not been internalized as the motivation and priority for undergraduate teaching laboratories.5,6 The necessity and value of laboratories as part of chemistry education have largely been taken for granted, and a review of the objectives put forth for laboratory courses leads to the conclusion that laboratories do not generally achieve their purposes.1,7 Some academic scientists have explicitly argued that chemistry laboratory courses should be removed from undergraduate curricula completely.8 To counter these arguments, the utility and effectiveness of differing laboratory course formats have been debated. A “taxonomy of laboratory instruction styles” was put forth which includes describing the outcome, approach, and procedure in order to determine whether a laboratory is considered expository (traditional), inquiry, discovery, or problem-based.9 In a survey representative of the institutions with American Chemical Society accredited chemistry programs, 91% responded that laboratory guides often or almost always provided step-by-step directions indicating a traditional laboratory format, and only 8% self-reported using inquiry laboratories.10 However, results of the research on the impact on learning for differing lab formats are varied.1,11 Research on the most effective curricula and pedagogy for chemistry laboratories has continued in many directions. Prior
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LABORATORY LITERATURE REVIEW Teaching laboratories first developed in the early 1800s out of a need to train apprentice chemists in composition analysis.2 By the late 19th century, American universities and high schools had incorporated laboratories as required elements of chemistry instruction but had moved from an apprenticeship experience to the more traditional expository laboratory still used by many today.2 In 1935, Schlesinger outlined what he believed to be the goals of laboratory instruction (ref 3, p 525): 1. To illustrate and clarify principles discussed in the classroom, by providing actual contact with materials. 2. To give students a feeling of the reality of science by an encounter with phenomena which otherwise might be to them no more than words. 3. To make the facts of science easy enough to learn and impressive enough to remember. © 2014 American Chemical Society and Division of Chemical Education, Inc.
Published: July 31, 2014 1446
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studies have probed how students’ attitudes, beliefs, and perceptions about chemistry and chemistry classes affect learning.12−15 The underlying assumption in each of these studies is that if students perceive chemistry as positive and expect certain aspects of how they can come to understand and internalize knowledge in chemistry, they will be better able to learn chemistry.12−15 Students’ expectations of how they will learn chemistry vary significantly from what instructors perceive as students’ expectations, and this gap increases through the first two undergraduate general chemistry courses.13 Since students’ expectations diverge from those of their instructors, it is not surprising that research also shows that laboratories focused on reinforcing concepts do not enhance student understanding of chemistry.1 The use of discussion in laboratories to improve student understanding has been implemented in limited manners or only with lecture demonstrations previously, with no data on the students’ perceptions or expectations.16−18 This paper outlines the design of a novel and effective General Chemistry Laboratory curriculum based on a longitudinal, active research process of assessing student expectations, perceptions, and experiences as changes were implemented. The primary goal for the General Chemistry Laboratory courses as set by the instructor and presented to the students was to actively engage students in advancing their understanding of the chemical concepts via laboratory observations and experiences. The main means of achieving this goal was including guided student discussion after each laboratory was performed.
Table 1. Student Participation in Surveys and Interviews for General Chemistry (GC) Group
Surveys, N
Interviews, N
Fall 09 PreGC1 Fall 09 PostGC1 Spring 10 PostGC2 Fall 10 PreGC1 Fall 10 PostGC1 Spring 11 Post GC2 Fall 11 PostGC1 Spring 12 PostGC2 Fall 12 PreGC1 Fall 12 PostGC1 Spring 13 Post GC2
339 331 265 357 330 262 286 264 286 262 251
19 15 15 24 15 15 20 13
followed an open-ended interview guide with questions that probed students’ previous experiences in chemistry and laboratories, as well as their current academic experiences. Interviews were also completed with the lab instructor and teaching assistants for the discussion sessions for Spring 2012. The same author performed all interviews, which were recorded electronically, with student permission, and on paper. Notes and transcriptions were coded and analyzed using grounded theory.19 Quotations included as data throughout this paper represent the common themes that emerged rather than isolated viewpoints.
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ASSESSMENT OF CONVENTIONAL LABORATORY The main goal of the course instructors in assigning laboratory work was primarily illustration and observation of key chemical concepts with very little emphasis placed on teaching lab procedures themselves. This goal of learning about chemistry from the lab was told to students by both the lecture and laboratory instructors at the beginning of the course. However, an overwhelmingly high percentage of incoming students felt that learning lab techniques was a goal of the course (Figure 1), and this fraction decreased only slightly even after instruction in the course. Although the goal of learning lab techniques was never highlighted by the laboratory instructor, students were of course expected to perform very basic procedures for which
SETTING AND METHODS The population for this study was the General Chemistry students concurrently enrolled in the two-semester class and laboratory at a small, private university. Each year, about 350 to 400 students were enrolled during the fall semester and approximately 300 students in the spring. About 90% of the students in General Chemistry were freshmen. The lecture portion of the course consisted of three 50 min classes per week taught by instructors other than the lab instructor. Students attended laboratory sessions in sections of fewer than 50, led by the laboratory instructor and assisted by teaching assistants. The initial review of the lab course began in Fall 2009. From Fall 2009 through Fall 2011 the laboratories were traditional verification laboratories coinciding with the lecture material. In Spring 2012, the lab course was redesigned to include both laboratory work and guided student-centered discussion. Students participated in surveys online at the end of the semester and completed the questions confidentially. Surveys were voluntary with minimal extra credit awarded for participation. Response rates were greater than 80% for each administration with the number of students listed in Table 1. Each survey included 25 Likert-scale questions from CHEMX, a validated instrument used to assess cognitive expectations in learning chemistry.13 Of those questions, only nine of them were focused on the chemistry laboratory. Every survey also included questions written by the authors regarding specific student perceptions of previous chemistry classes and the current course and lab. Interviews were performed with approximately 5% of the student population each semester from Fall 2009 through Spring 2012, as shown in Table 1. The students who were asked for an interview were selected at random from all those who had agreed to participate via the survey. Interviews
Figure 1. Percentage of students who “agree” or “strongly agree” over the first year of General Chemistry (GC). 1447
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the spectroscopy without realizing they were actually determining reaction equilibrium or reaction rate order. These observations tell us the issue was not with the laboratories themselves, yet with how the lab experience was structured for completion by students.
they were given detailed guidance in order to obtain data in the laboratories. Students’ reported high school chemistry experiences varied greatly, and these experiences impacted students’ perceptions of General Chemistry Laboratories in a similar fashion. For students with very little previous experience manipulating equipment, interviews revealed that this activity became the focus of their time in the lab consuming the students’ cognitive load by the actual process of performing the lab. One student felt, “There wasn’t a lot of focus on teaching chemistry, just teaching the procedure.” For the majority of the students interviewed, little thought was given to the chemistry of the lab itself. One student expressed it this way, “I didn’t learn chemistry, but I did learn a lot about lab equipment.” The main theme from the interviews after students had completed the first semester of General Chemistry was that most students do not view the laboratory as a place for learning. Instead, they see the lab as an exercise to obtain the required data. In general, high school laboratories were viewed as fun experiences rather than a means of learning or furthering one’s understanding of chemistry. Students brought this expectation into their college experience. They report that they think about the chemistry in lab itself afterward only if it is necessary in order to complete the lab report. One student stated, “Doing the lab and doing the write up for the lab equals getting numbers; you think about it later.” Most students focused on completing the required steps of each lab without thinking about what they were doing or why they were doing it. While there were some students who wanted to understand the chemistry behind each step as it was completed, they were in the minority. Most students really did view the lab as an exercise in manipulating materials in order to obtain data so that they could complete the lab report at a later time. Another student stated, “In the lab you are actually doing the experiment; you don’t need to understand the concepts.” While students recognized that the lab subjects coincided with the material covered in the lecture portion of the course, most students nevertheless did not further their understanding in chemistry from traditional lab experiences. As an illustrative example, the instructors designed and included a set of three laboratories specifically to incorporate greater analytical chemistry applied to key chemical concepts. For 3 weeks in a row, spectrophotometers were used to collect data to demonstrate Beer’s law (week 1), then to observe equilibrium (week 2), and finally to observe reaction rates (week 3). This instigated unexpected responses, as the majority of students were not able to differentiate between the concepts being illustrated by the laboratories. They instead reported feeling that they were repeating the same procedure over and over rather than realizing they were using Beer’s law to observe very different concepts in chemistry. Many students made statements such as, “There was too much emphasis on Beer’s Law,” and indicated that they did not understand Beer’s law as an analytical technique. This set of three laboratories was designed in tandem by a chemistry professor and instructor to incorporate spectroscopy yet mainly to illustrate the concepts of equilibrium and kinetics. Despite high quality laboratory experiences aligned with the lecture curriculum, students did not use the laboratory to enhance their understanding of chemistry. From interviews, students overwhelming saw the laboratories as disconnected procedures that were simply performed without an understanding of the science. They were more focused on performing
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LABORATORY COURSE REDESIGN To address the observations that the General Chemistry Laboratory was not succeeding as a place of learning, we tried a variety of small changes. These included updated lab reports, inclusion of discussion time at the end of each lab, addition of a student-designed inquiry lab, and a focus by the instructor on learning from lab. However, the implementation of these changes went unnoticed by the students, and they continued to see the lab as an exercise in manipulation rather than learning as can be seen in Figure 1. More universal structural changes were necessary to make the laboratories effective in increasing students’ understanding of chemistry. In Spring 2012, broad changes were implemented in the General Chemistry Laboratories, unlike conventional approaches more commonly found in current literature. The laboratory time was increased to 3.5 h sessions meeting every other week with smaller discussion sessions meeting for 1 h on the weeks between laboratories. As the total instruction time over the semester was not significantly changed, no changes were made to the course credit or the time and credit for the lecture portion of the course. For the most part, existing experiments were modified to increase the students’ independent analysis and introduce areas for discussion. However, in some cases, new experiments were developed by adapting literature procedures to the equipment available and discussion format. Prelab quizzes were replaced by prelab assignments that required students to outline the data they needed to collect and the equipment they would need, perform any preliminary calculations, and create a workflow outlining the lab procedure. During the first week of each laboratory experience, students turned in the prelab assignment, performed the lab, and collected the data to be recorded in a format of their own design. Short prelab lectures were held prior to students’ performing the lab. In the first week after performing the lab, students were required to complete prediscussion exercises. These exercises included initial data analysis such as calculations or graphing, as well as some basic interpretation of results. The prediscussion exercises were due at the beginning of the 1 h discussion session that met 1 week after the lab was performed. In the discussion sessions, a teaching assistant gave students questions to discuss in small groups relating to the laboratory followed by full class discussion. This cycle of questions in groups followed by class discussion continued for the hour. Students sat at circular tables designed for small group discussion.20 Discussion sections were limited to 24 students at a time. For some laboratories, class data was pooled for comparison, or new data was collected so that students could do further analysis. Attendance at discussion sessions was required, and students were assessed on their participation (∼10% of lab report grade). After the discussion session, students were required to further analyze the data and draw conclusions by completing postdiscussion and postlab questions. These questions focused on students’ providing explanations and demonstrating understanding of the chemistry. Students were also asked to extend their knowledge to situations beyond what was experienced in the lab. Lab reports were then due 2 weeks after the completion 1448
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not just doing the experiments. I mean you’re trying to understand what you’re doing which is much better, because I think first semester I just sort of did the labs to get a grade.” Students responded differently to the discussion sessions depending on their level of confidence with the material. Students who more frequently struggled to understand the concepts reported that the discussion sessions helped due to reiteration of ideas, explanation of portions of the lab, and group discussion of data interpretation. One such student stated, “I usually came out [of discussion session] with a better understanding of the concepts.” Another student said, “During lab I kind of was just following procedures, so I wasn’t thinking about it that much; but during discussion it actually really did help understand the concepts.” Students who already felt comfortable with most of the content preferred being asked questions that addressed the concepts beyond the lab and appreciated the chances to participate in small group discussions. One student felt that discussion sessions, “Made the lab more relevant...discussion sessions helped to create a general idea so it helped connect one lab to the next.” In general, most students saw the value of the discussion sessions to their education and preferred them over weekly laboratories. A student recommended continuing discussion sessions stating, “It helps to actually see the data and then understand what we were actually learning in class.” The lab instructor and discussion session teaching assistant interviews validated the varying student reports of informal feedback and activity during discussion sessions. Upon implementation of required prelab assignments and structured postlab discussions, students were made to think about the lab experiences and the chemistry involved.
of the lab and prior to the start of the next lab. The initial and revised schedule of laboratories and an example of a revised lab are included in the Supporting Information.
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PRELIMINARY RESULTS Student perceptions of the discussion sessions were assessed with survey questions, and the responses to selected questions are shown in Figure 2. Each semester the majority of students
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CONCLUSIONS We have found in studies at our school that, whatever goals the instructor may set for the introductory laboratory course, the students strongly believe that the primary goal of the lab is to create exercises in laboratory techniques. This belief is sufficiently dominant for our students that it displaces the students’ focus away from instructor goals. Students will perform laboratories without thinking or visualizing if such tasks are not required of them. Furthermore, we were unable to change the students’ perspectives with minor curricular or pedagogical changes. This was despite the fact that our choices of experiments and assignments were specifically targeted toward deepening students’ understanding of the concepts presented in lecture. We have found that laboratories must be specifically designed and structured in order to require students to think about the chemistry by discussing the data, visualizing the particles, and being required to address the concepts rather than simply following a procedure and completing a report. For many students, first-year undergraduate laboratory courses are the first time they will be asked to critically analyze scientific data in order in draw concrete conclusions. Although this skill is implicit in a traditional lab report, most students fail to master it (or even realize that they should) without the structured guidance of devoted class time. The modifications made to the lab experiences within this study did increase the educational value of the laboratories as perceived by the students. Students need to be encouraged to think, visualize, and make meaning from laboratories, and they were given explicit instruction in how to do so. Performing manipulations within the lab is not the main point of the lab
Figure 2. Student responses to survey questions regarding discussion sessions.
agreed that discussion sessions helped them understand chemical concepts, helped them connect the class and lecture material, and were a good use of time. Student survey responses indicated that the discussion sessions did offer students time to contemplate lab activities. Survey questions asked students when they performed certain functions associated with the laboratories, whether during the actual lab, right after the lab, during discussion sessions (once implemented), while writing the lab report, or when studying for a chemistry exam (questions available in Supporting Information). Students reported reflecting on observations, visualizing on a molecular level, analyzing data, interpreting data, and incorporating lab and class knowledge during discussion sessions. This contrasts to surveys conducted prior to the incorporation of discussion sessions in which students reported that they did most of these activities while completing the lab report, which was often done right before it was due. The required discussion sessions gave students structured time to think about the aspects of the lab and gain more from the lab experience. Interviews with students elicited various themes about discussion sessions. Because those students that were interviewed had experienced the traditional lab setting for Fall 2011 and the modified laboratories in Spring 2012, they were able to compare and contrast the formats. One student saw the new laboratories as, “More discussion based and you’re 1449
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(15) Walker, J. P.; Sampson, V.; Grooms, J.; Anderson, B.; Zimmerman, C. O. Argument-Driven Inquiry in Undergraduate Chemistry Labs: The Impact on Students’ Conceptual Understanding, Argument Skills, and Attitudes Toward Science. J. Coll. Sci. Teach. 2012, 41 (4), 74−81. (16) Demoin, D. W.; Jurisson, S. S. Chemical Kinetics Laboratory Discussion Worksheet. J. Chem. Educ. 2013, 90, 1200−1202. (17) Miller, T. L. Demonstration-Exploration-Discussion: Teaching chemistry with Discovery and Creativity. J. Chem. Educ. 1998, 70, 187−189. (18) Stevens, K. E. Experimentation and Group Discussion as a Means of Determining Solubility Rules. J. Chem. Educ. 2008, 77, 327− 328. (19) Strauss, A.; Corbin, J. Basics of Qualitative Research: Techniques and Procedures for Developing Grounded Theory; Sage Publications: Thousand Oaks, CA, 1998. (20) Gaffney, J. D.; Richards, H. E.; Kustusch, M. B.; Ding, L.; Beichner, R. Scaling Up Education Reform. J. Coll. Sci. Teach. 2008, 37 (5), 48−53.
experience; gaining greater understanding of the chemical phenomena being observed is what makes laboratories valuable. While students might still expect that the actual lab performance is the main process in the lab, they are given an opportunity to enhance their conceptual understanding in chemistry if they are required to actively discuss the lab. While this study was focused on General Chemistry Laboratories, the conclusions are also informative for high school and upper level college laboratories. Students must be required to think about laboratories and be given the structure and time needed to do so.
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ASSOCIATED CONTENT
* Supporting Information S
Schedule of laboratories; example of a reformatted lab. This material is available via the Internet at http://pubs.acs.org.
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AUTHOR INFORMATION
Corresponding Author
*E-mail:
[email protected]. Notes
The authors declare no competing financial interest.
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REFERENCES
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