Students' Attitudes toward and Conceptual Understanding of Chemical

Research: Science and Education edited by

Chemical Education Research

Diane M. Bunce

Students’ Attitudes toward and Conceptual Understanding of Chemical Instrumentation

The Catholic University of America Washington, DC 20064

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Larry S. Miller,* Mary B. Nakhleh,** John J. Nash, and Jeanne A. Meyer Department of Chemistry, Purdue University, West Lafayette, IN 47907-2038; *[email protected], **[email protected]

As the use of instrumentation in chemical research continues to rise, it is becoming increasingly important to make students (especially chemistry majors) aware of the different uses and applications for scientific instruments, how such instruments are used in the lab, and, perhaps most importantly, the chemical principles underlying the instrumentation. There are many ways that instrumentation might be implemented in the undergraduate curriculum to achieve these goals. For example, chemistry students might use instrumentation to collect data that would then be analyzed and interpreted to construct an understanding of a particular chemical phenomenon. Prior research in this area indicates that the use of instrumentation in the lab has an impact on both students’ conceptual understanding of chemistry and their attitudes towards science. Nakhleh and Kracjik found (1, 2) that secondary students had different levels of conceptual understanding of acid– base phenomena depending on whether the students performed an acid–base titration using a colored indicator, a pH meter, or a computer-interfaced pH probe (which allowed real-time graphing of the pH titration curve on the computer screen). Eichinger, Auberry, and Nakhleh found (3) that college biology students had generally favorable attitudes toward microcomputer-based lab experiments. Moreover, these students felt that the graphical display of data associated with these types of experiments contributed the most to their understanding. Malina and Nakhleh also found (4) that the primary benefits of the CCD spectrophotometer, from the point of view of upper-level college students, were all related to the graphical display of data. All of these studies focused on students’ interactions with either a single instrument or with several instruments (over the course of several experiments). The study described here differs from earlier work in that one group of students was observed as they used three different instruments and two different lab techniques to complete a single experiment. Theoretical Framework Distributed cognition proved to be a powerful theoretical framework for this study. Distributed cognition can be viewed as an extended form of constructivism in that it posits that individuals construct knowledge through a complex set of interactions with other people and with the artifacts in their environment (5). In our study, these artifacts are the scientific instruments and associated techniques used in the experiment. We collectively refer to these instruments and techniques as “tools”. The ability to study these interactions was vitally important in this study, because the lab experiment under investigation involved groups of three or four students using four different tools. Distributed cognition rewww.JCE.DivCHED.org

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gards the context as an integral part of the knowledge construction process; therefore, it was essential to observe the interactions of the students with each other and with the laboratory instruments and techniques to begin to understand this process of knowledge construction. Based on the results of previous research, it was hoped that the following three questions could be addressed within the theoretical framework described above. 1. What were students’ attitudes toward using instrumentation in the laboratory? 2. How did students relate the underlying chemical concepts to the instrumentation? 3. How did working in a group affect student attitudes toward, and their conceptual understanding of, instrumentation?

These questions were addressed using a qualitative research design because this approach enabled us to “capture” students’ attitudes and opinions and to analyze students’ interactions in the laboratory setting. Moreover, a qualitative research design offered opportunities to explore our research questions in ways that quantitative studies could not. For example, field observations in the actual laboratory setting were essential pieces of data that were not amenable to quantitative analysis. Further, a qualitative design allowed us the flexibility to respond to new paths of investigation as they emerged. The qualitative design provided a powerful framework that allowed us to describe and understand the whole process of the laboratory experience rather than to simply examine the effects of discrete variables. Setting Within this framework, we sought to understand the interactions of a group of freshman chemistry majors engaged in a lab activity that required the use of a variety of tools. The setting selected for this inquiry was CHM 126 (spring 2001), a second-semester general chemistry course for chemistry majors that covers topics such as thermodynamics, equilibrium, kinetics, electrochemistry, transition-metal chemistry, and nuclear chemistry. CHM 126 is a five-credit-hour course, and students meet each week for three lectures, one lab, and one recitation. All 44 students in the course met together for the lectures, but were divided into smaller sections for recitations and labs. In each of the lab–recitation sections, students worked in the same groups of three or four for both lab experiments and group problems given in recitations. Before the students performed the experiment, the fundamental aspects of infrared (IR) spectroscopy, flash chromatography, thin-layer chromatography (TLC), and gas chromatography (GC) were discussed in lectures. In addition, during the first two weeks of the semester, students com-

Vol. 81 No. 12 December 2004

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Journal of Chemical Education

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Research: Science and Education Table 1. Student Responses to the Scaled-Response Survey Questions Meana

Question Comfort Operating the Instrument 1. I feel comfortable operating the Rotovap.

3.57

3. I would be able to construct a flash column without help from anyone.

4.21

8. If my lab group could only choose one member to run the IR for the group, the group would choose me.

2.86

17. I am the most qualified person in my group to operate the IR.

3.21

22. Operating the GC is difficult.

2.36

Conceptual Understanding of Instruments 5. I could explain to another student how a GC works.

3.79

11. If I were given an IR spectrum, I would be able to deduce the structure of the molecule.

3.71

15. I feel comfortable interpreting a gas chromatogram.

3.64

18. I understand the role of silica gel in a flash column.

4.14

21. Before receiving my lab score, I felt confident in my abilities to identify the two unknowns.

3.57

Effects of Errors, Mistakes, and Reworked Procedures 4. I felt uncomfortable when procedures for this experiment were modified as the experiment progressed.

2.71

9. I enjoyed the challenge of making adjustments and modifications to the project as the experiment progressed.

3.29

12. In this experiment, I gained an appreciation for how work is carried out in research laboratories.

3.50

19. I got frustrated when operations had to be repeated in this experiment owing to equipment failure.

3.43

20. This experiment made me doubtful of my choice of major.

1.93

Group Dynamics 2. Our group allowed everyone a chance to operate the IR.

3.46

7. In my group, I became the expert in operating one of the instruments.

3.21

13. I feel that both men and women have an equal opportunity to contribute in my group.

4.07

16. If an operation was carried out incorrectly during the experiment, an individual got blamed for the mistake.

2.64

23. I would have preferred doing this experiment on my own, rather than with my group.

2.14

General Questions 6. I felt my TA had a firm understanding of the procedures required in this lab.

a

3.93

10. If I were to do this experiment again, I would be able to do it in less time.

3.93

14. If an internship for freshmen chemistry majors that required knowledge of IR was available this summer, I would feel confident applying for the job.

3.86

24. I think the skills I learned in this experiment will be valuable to me in the future.

3.64

25. I enjoyed doing this experiment.

3.36

Strongly disagree = 1; strongly agree = 5.

pleted an assignment on IR spectroscopy using the software package, IR Tutor (6). In this assignment, students tabulated the characteristic vibrational frequencies, intensities, and types of vibrational motions, associated with each of several different organic functional groups (the students were allowed to use their tables during the experiment to help them interpret IR spectra). Finally, the GC module of ChemPages Laboratory (7) was completed by the students (as time permitted) while they were in the lab.

CHM 126 by two of us (JJN, JAM). We primarily designed the experiment to

Experiment The experiment used for this study, “How Can Flash Chromatography, Thin-Layer Chromatography, Gas Chromatography and Infrared Spectroscopy Be Used to Separate and Identify Components in a Mixture?”, was developed for

• illustrate how multiple sources of information (data) are often used in science to answer questions, and

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• provide opportunities for students to experience, firsthand, several spectroscopic and chromatographic techniques that are common in chemistry, • provide opportunities for students to begin to develop skills (both manipulative and interpretive) in both spectroscopy and chromatography that would continue to be supported (i.e., used again) in subsequent chemistry courses,

• provide additional opportunities for students to develop critical-thinking, problem-solving, and time-management skills.


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Research: Science and Education

Table 2. Student Responses and Frequency of Responses to the Survey Questions Question Which instrument did you find easiest to use?

Which instrument did you find most difficult to use?

For which instrument do you understand the most about the chemical principles involved in its use?

For which instrument do you understand the least about the chemical principles involved in its use?

What was your most enjoyable experience in this experiment?

What was your least enjoyable experience in this experiment?

Response

f

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f

TLC

5

simple

9

GC

4

TA did others

2

Rotovap

2

familiar

1

Flash Column

2

IR

1

Rotovap

5

complicated

5

TLC

4

tedious

2

IR

2

not explained

1

GC

2

old equipment

1

Flash Column

1

"it was a piece"

1

never used it

1

Flash Column

4

explained

5

IR

4

simple

3

GC

3

familiar

1

Rotovap

1

1

TLC

1

"get answers and knew they were correct"

Rotovap

6

not explained

3

IR

4

unclear explanation

2

GC

2

no physical interaction

1

Flash Column

3

GC

2

IR

2

TLC

1

relating lecture to lab

1

group work

1

identifying unknowns

2

TLC

5

waiting for equipment

3

GC

1

interpreting results

1

old equipment

1

trying to finish in time

1

The experiment began in the fourth week of the semester and required three lab periods (weeks) to complete. The experimental goal of the experiment was for students, working in groups of three or four, to separate and identify two organic compounds (each containing a single functional group) in an unknown solution using a variety of instruments (IR, GC) and experimental techniques (flash chromatography, TLC). For most of the students in CHM 126, this experiment was their first exposure to these particular tools. Full details of the experiment are provided as Supplemental Material.W However, to summarize, the students first separated the two organic compounds in the unknown solution using flash chromatography (8). The composition of the eluent, a solution of pentane and ether, had been determined by the students in a preceding experiment (9). Forty fractions were www.JCE.DivCHED.org

Reasons Given

collected from the column and each fraction was analyzed by TLC (along with five known compounds). Those fractions that contained only one of the two compounds were combined, and the solvent was removed using a rotary evaporator. Finally, the two (separated) compounds were analyzed using both IR and GC. For the GC analyses, each group of students also analyzed a solution containing one of the five known compounds so that the GC retention times for the known compounds were available for comparison. After the students had completed the experiment, they had three different sets of data that they could then use to identify the two compounds in their unknown: (i) TLC Rf values for both the unknown compounds and the known compounds, (ii) IR spectra for the unknown compounds, and (iii) GC retention times for both the unknown compounds and the known compounds.


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Study Design

Field Observations Only one of the three recitation–lab sections (a total of 12 students) was examined. This restriction allowed the observer (LSM) time to establish a rapport with the students and it also permitted the recording of observations for all of the students simultaneously. The students were arranged into groups during the first recitation period based primarily on the proximity of their living quarters (i.e., to facilitate preparation of group lab reports). During the lab sessions, the observer recorded field notes about the interactions and conversations of the 12 students (three groups of four students) as they performed the experiment. Surveys During the week immediately following the completion of the experiment, surveys were made available to all of the students. The survey was constructed towards the end of the experiment, and the questions were formulated based on observations made while the students were performing the experiment. The survey consisted of four demographic questions (gender, major, year in school, and lab section), 25 scaled-response questions (1 = strongly disagree to 5 = strongly agree), and six free-response questions. The scaledresponse questions were categorized in five major areas: (i) comfort operating instruments, (ii) conceptual understanding of instruments, (iii) effects of errors, mistakes, and modified procedures, (iv) group dynamics, and (v) general questions. The scaled-response questions included five questions from each of these categories, but questions from each category did not appear consecutively on the survey. Student responses for the scaled-response questions are summarized in Table 1. The six free-response questions asked students to identify which instrument they felt was the easiest or most difficult to use and which was the easiest or most difficult to understand conceptually. They were also asked to identify their most or least enjoyable experience during the experiment. After each free-response question, students were asked to explain their choice. Of the 44 surveys taken by the students, 14 (32%) were returned. This low return rate may have been due, in part, to the stringent procedures mandated by the Purdue University Internal Review Board, which require that students voluntarily pick up, complete, and return surveys (i.e., researchers are not allowed to distribute or collect surveys.). However, the surveys did provide sufficient information about trends to generate interview questions. Student responses for the free-response questions are summarized in Table 2. Interviews After the laboratory experiment was concluded, six volunteer students (four males, two females) participated in interviews of about 45 minutes in duration. Five of these six students were in the section that was observed during the experiment. The interviews consisted of an individual interview with a male, an individual interview with a female, a focus group of two males, and a focus group of one male and one female. These interviews will be referred to, respectively, as Interview 1, Interview 2, Focus Group 1, and Focus Group 2, which also coincides with the (chronological) 1804


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order in which the interviews took place. A note taker was also present during all of the interviews. The note taker was trained in qualitative research methodology and had taken notes for interviews for other research projects. At the end of each interview, the interviewer (LSM) and the note taker compared notes to improve reliability. Trends noted from both the field observations and the survey responses were used to develop the interview protocol, which consisted of six sections. In the first section, the interviewer introduced himself, explained the purpose of the interview, the voluntary, anonymous nature of their participation, and collected general background information. Students were then given the opportunity to examine a copy of the experiment to refresh their memories. In the second section, the interviewer asked general questions about the experiment. For example, the students were asked to share their thoughts about the purpose(s) of the experiment as well as the professor’s intentions for selecting this experiment. In the third section, questions were asked about specific trends drawn from the field observations and survey responses (e.g., time issues, clear explanations, simplicity). In the fourth section, student attitudes toward the experiment were probed. Specifically, students were asked to describe their most and least enjoyable experiences, any equipment failures, and any especially frustrating events. They were also asked to describe any aspects of the experiment that they found particularly valuable. Section five probed students’ conceptual understanding of the instruments. For example, the students were asked about chemistry concepts associated with the experiment and how their understanding of these concepts was used during the experiment. They were also asked how their conceptual understanding might have changed as a result of the experiment. Finally, students were invited to ask any questions that they had. Selected interview questions and student responses are shown in Table 3. Findings Five primary themes were identified from the various data sources. We defined a primary theme as one found in at least three of the four data sources (i.e., field observations, scaled-response survey questions, free-response survey questions, and interviews). The five primary themes were: simplicity, clear explanations, group work, valuable skills, and conceptual understanding. Each of these themes will be discussed separately.

Simplicity In the free-response survey questions, TLC was identified by the students as both “simple” and “complicated”, making it simultaneously the “easiest instrument to use” and the second “most difficult instrument to use” by frequency count. This paradox appeared to relate to the student’s definition of “simple”. Some students felt a tool was simple if it was easy to operate. For example, the students from Focus Group 2 said that a procedure was simple if “almost anyone can do it with little knowledge of what’s going on”. The students from Focus Group 1 called this definition of simple “good simple”. Therefore, they classified GC as “good simple” because all they had to do was “enter stuff and get [a] print out”. The student from Interview 2 felt that something was


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Research: Science and Education Table 3. Selected Student Responses to Interview Questions Question

Interview 1

3. Purpose(s) of the experiment?

• separate and identify unknowns using different methods

4. Professor's intentions?

• to understand and use GC, IR, TLC to find out what is in a mixture • real life—you would have a substance you'd want to separate

• exposure to a variety of different ways of doing different things and identifying different things

5a. What kind of explanations would best help you understand an instrument?

• clear—in lab it is step-by-step • no assumptions that you have done something before • no inconsistency with directions and physical materials • what you need to do (no excess info)

• not familiar with • tell A–B and B–C each instruments—needed REALLY step of instead of "just do specific directions—every detail this" • make sure lab is in chronological order • pictures help simplify procedures

5d. Which is preferable…(a) lecture on concepts before lab or (b) using an instrument in lab before lecture?

(a) you know how it works, broad ideas narrow to how you use it

(a) I would like to know how it (a) not just doing "voodoo" (a) best sequence for works and why it works before I but knowing why we do learning actually do it what we are doing and you do not forget to do things

7a. What does simplicity mean for you?

• least amount of error possible • even if you deviate from directions, it still works • not one extra drop makes it invalid • less likely to have to redo • just stick it in and it goes

• easy to use • complicated inside is still simple if easy to operate • directions clearly shown or clearly written

• good simple vs. bad simple • GC was good simple— enter stuff and get print out • TLC was bad simple— had to do 40 different TLC • simple is not better—do not learn as much and can get bored

• almost anyone can do it with little knowledge of what is going on

7b. For you, how does simplicity relate to the concepts?

• you could understand if deviations would effect results, or what kind of results it would give

• all simple to understand

• Individual steps not complex, analyzing data more difficult-thinking lab

• had to learn quite a bit to understand what is going on

7c. For you, how does simplicity relate to the instruments?

• TLC results veered, no dots sometimes, bad Rf, difficult to use plates which were too long for bottles, had to cut ends of plates, and inconsistent

• TLC was simple—very few steps and very clear how to do it • flash chromatography was not simple—a lot of step in prep for that

• the individual simple parts of the lab make a complicated whole

• physical usage was simple • preparing samples not necessarily simple • TLC was complicated because we had so many • to do one would have been simple

9. How comfortable did you feel using instruments?

• irritated with old IR • stuff we are using is not very current

• comfortable overall • would work with all this • neat that instructor is equipment again with getting us involved with stuff we comfort might use in the future

11. How would experiment be different if you worked alone instead of in groups?

• would have been unfeasible to ever do • easier to rely on other people • if you do not understand 1 thing, likely that someone else will get it

• would have taken a lot longer • good in groups to ask each other questions • can double check our work

• would have taken 12 • group works well— labs someone usually understands • group kind of split into if I do not tasks for each member • progressed in sections together but did split up the work

12. What valuable skills did you learn from this experiment?

• using IR—more experiences to draw on future • know what can go wrong • know shortcuts

• GC—could potentially actually use—never seen anybody using TLC • (IR?)—could be? I guess just like GC

• being careful and • deduction • resolving conflicting data organized • critical thinking • organizing people into a functioning group

16. Which instrument did you have • IR, can build complete "thing" the best conceptual understanding from functional groups of?

• flash chromatography—got explained in a lot of detail in lecture

• IR tells functional groups and structure

17. How was your understanding of concepts used during the experiment?

Interview 2

Focus Group 1

Focus Group 2

• use different methods of chromatography • learning lab techniques of actual chemists

• to utilize tools to identify unknowns in comparison with knowns • to learn to use the instruments

• use IR—will use in several • experience with equipment labs • different chromatography used in labs • practice for learning concepts

• mainly just focused on completing • not really thinking about how • did not think about chem task things were working in lab during lab time, only after lab—just collecting data during lab

18. How has your understanding of • never done a lot with IR before— these concepts changed after was unsure of practicality from only performing the experiment? lecture • IR a lot simpler to use than descriptions made it seem • Rf values can be useful, too

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• learning about different equipment—did not know how they actually worked • never heard of some before • writing lab report put it all together • understand why people might actually want to use these machines


•does not change understanding much— chromatography all works the same • had already gone over IR in class

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• explaining to the point that you know where to begin and proceed • not necessarily every single detail • ideally no big surprises in lab

• enjoyed it—never really used in high school • comfortable using it now and will be later

• IR for same reasons

• I tried to, but everyone else just wanted to get done

• had done most of it before except the rotovap • help to understand how equipment is used by scientists • learned how precise, accurate, and careful scientists have to be • understand how the graphs are made and what they mean


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“simple” if it was “easy to use”, and the directions were “clearly shown or clearly written”. For her, TLC was simple because there were “very few steps” involved, and it was “very clear how to do it”. On the other hand, flash chromatography was not simple to her because the preparation of the column involved several steps, and she felt that some of the directions were not sufficiently detailed. The student from Interview 1 felt that something that was “simple” had the “least amount of error possible”. When he was asked to describe his ideas about how simplicity related to the tools used in the experiment, he said that TLC was not simple because the TLC plates did not fit into the developing chamber properly, which led to poor separations and inconsistent results. The number of repetitions for a particular procedure also affected students’ views about whether a tool was simple to use. Focus Group 2 students felt that TLC was complicated because they had to run many trials, whereas to run only one trial would have been simple. The students from Focus Group 1 referred to this repetition as “bad simple”, adding that something that is simple is not necessarily better because you “don’t learn as much and can get bored”. To the students, simplicity seemed to be a multifaceted construct of both positive and negative factors. Certainly one of the factors seemed to be ease of operation (a positive factor); another seemed to be freedom from error (a positive factor). Repetition was regarded as a negative factor.

Clear Explanations In general, the students interviewed felt that the explanations of instruments given in the lectures were clear and provided them with an adequate understanding of the chemical concepts underlying the instrumentation. All of the students interviewed valued a clear explanation and said that the lectures (in which instruments are described) should come before the lab in order to make instrument operation clearer and simpler. For example, the student from Interview 2 stated, “I’d like to know how it works and why it works before I actually do it” indicating that a clear explanation consists of two components: (i) a description of how to use a particular tool and (ii) a description of the underlying chemistry concepts for that particular tool. A student from Focus Group 1 said that when provided with a clear explanation before operating an instrument, “we’re not just doing voodoo” but rather understand why each step is important so that “you don’t forget to do things”. It is clear that the students much preferred having a conceptual understanding of how an instrument functioned before they learned to operate it so that they could better understand how the physical manipulations associated with using the instrument related to their conceptual understanding of how the instrument worked. However, the students had different opinions about what constituted a “clear explanation”. Focus Group 2 felt that the lab manual should provide explanations “to the point that you know where to begin and proceed”, but “not necessarily every single detail”. Similarly, the student from Interview 1 felt that the type of explanation that best helped him to understand a tool was one in which there were “no assumptions that you’ve done something before”, but only conveyed information about “what you need to do (no excess info)”. The

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student from Interview 2, on the other hand, felt that she “needed really specific instructions—every detail” because she was “not familiar with the instruments”. Finally, Focus Group 1 felt that the best explanations were “in chronological order”, included pictures to “help simplify procedures”, and should “tell A–B and B–C each step” instead of “just do this”. Students generally felt that the computer modules were also useful as explanatory tools. Students seemed to find IR Tutor more useful than the GC module of ChemPages Laboratory because IR Tutor helped them to understand both the theory of infrared spectroscopy and the interpretation of IR spectra. The students in three of the four interviews did not offer especially positive feedback about the GC module of ChemPages Laboratory, but this seemed to be a direct result of not having enough time during lab to use the software. The student from Interview 1, however, did use the ChemPages software, but he felt that it was not as useful as IR Tutor because he thought the laboratory experiment was primarily based on IR spectroscopy. He felt that IR was essential for pinpointing the identities of the unknowns because he could “build the complete ‘thing’ from functional groups”. In contrast, the GC provided much less useful information. Interestingly, even though they recognized that IR Tutor was a useful tool for learning the theory of IR spectroscopy, Focus Group 1 preferred the GC module of ChemPages Laboratory to IR Tutor. They preferred the GC module because it contained a large number of videos that illustrated instrument operation. These particular students also found their graduate instructor’s demonstrations of instrument operation extremely helpful. There was no demonstration of packing a flash chromatography column, either by graduate instructor or by computer module and, as a result, this group felt that it was “harder to visualize flash column with only a black and white diagram”. For these students, being able to visualize instrument operation was clearly an important component of a “clear explanation”.

Group Work The survey indicated that virtually all of the students liked working in a group. The survey data were supported by the many positive comments about group work in the interviews. Economic use of time and facilitation of learning seemed to be the main factors valued by the students. When asked to describe how the experiment would have been different if they had worked alone, all of the students interviewed said that the experiment would have taken a lot more time. The students also indicated that working in a group was beneficial to them because they were able to help each other understand the experiment and check each other’s work. In group work, a standard technique used by groups to complete a project is the assignment of different tasks or roles to individual group members. The lab group that contained the male from Focus Group 2 exemplified this approach. This student reported that his group assigned one person to stand in line (for the IR) while the other group members prepared for the next part of the experiment. For the TLC analyses, the group assigned one member to develop the TLC plates, one to visualize the TLC plates, and one to transport the TLC plates back and forth (from the lab bench to the main hood). This student also commented that there was an “arbitrary


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decision of who did what” within his group and group members usually volunteered to take on specific responsibilities based on who was closest to a particular instrument. Another lab group had a much less arbitrary method for assigning tasks. This particular group consisted of three males and one female, and two of the males constituted Focus Group 1. Focus Group 1 said that one of the (male) group members was good at math, so he did all of the calculations for the experiment. Another (male) group member had good lab techniques, so he did the bench work that required the most precision. The third male group member understood the chemistry concepts the best, so his role was to make sure the other group members understood the chemistry involved in the experiment. Focus Group 1 also said that their female group member “does what we tell her”, because “she is comfortable with that role”. Interestingly, this particular female was one of the students in Focus Group 2, and when she was asked to describe her experiences with group work, she said that she “didn’t know much, but tried to help as much as possible”. She added that she “gets stuck with the easy stuff ” but that she did not mind because she did not want to “mess up the lab for the other guys”. Although this assignment of roles might, at first, appear to be gender-related, it seems more likely that the assignment of roles was based on the group’s assessment of the aptitudes and abilities of its members. Moreover, the results for the scaled-response survey question, “I feel that both men and women have an equal opportunity to contribute in my group.” (mean: 4.07; third strongest agreement on the survey) suggest that gender-biased behavior was generally not an issue among the students.

Valuable Skills One of the scaled-response statements in the survey stated “I think the skills I learned in this experiment will be valuable to me in the future”. The data from this statement (mean: 3.64) indicate that many of the students felt that they had learned valuable skills during the experiment. Interestingly, though, when the students were asked during the interviews to identify these valuable skills learned from the experiment, they identified several different types of skills, ranging from higher-order thinking skills to more practical management skills. For example, Focus Group 1 felt that “deduction”, “resolving conflicting data”, and “critical thinking” were the most valuable skills that they learned from the experiment. These students felt that the entire experiment was based on “deduction”, and even though “chemistry” was at the heart of the instrumentation, deductive reasoning transcended the chemistry and was needed for the experimental data to make sense (especially when conflicting data were obtained). These students clearly enjoyed the opportunity to develop higherorder thinking skills and felt that these skills would be particularly useful to them in the future. In contrast, Focus Group 2 students valued management skills. They identified “organizing people into a functioning group” as one of the most valuable skills they acquired from the experiment. Students from Interview 1 and Interview 2 took a more procedural approach. They identified skills that were directly related to the tools themselves such as using GC or “knowing what can go wrong”.

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Conceptual Understanding Not surprisingly, the survey and interview results indicate that the tools for which the students felt they had the best conceptual understanding were those that had been described in the greatest detail (either in lectures, the lab manual, or the computer modules). For example, students identified flash chromatography, IR, and GC as instruments that they understood best in both the surveys and interviews. Indeed, these tools were discussed at length in the lectures, and students even completed an assignment using IR Tutor as their first lab activity (vide supra). Students identified the rotary evaporator as the tool for which they felt they had the least understanding (see Table 2). The evaporator was not described in either lectures or in the lab manual; rather, the TAs instructed the students on its use and operation during lab. Survey results suggest that many of the students were uncertain about how this instrument worked and its purpose in the experiment. In the interviews, the students were asked to describe how their understanding of scientific concepts was used during the experiment. Most of the students said that they did not think about concepts during lab. The student from Interview 1 said that he “mainly just focused on completing [the] task” because there were so many tasks that had to be completed during lab (i.e., he felt he did not have enough time to think about concepts). Focus Group 1 said that they only collected data during lab and did not actually think about the chemistry until after lab. The student from Interview 2 also admitted that she was “not really thinking about how things were working in lab”, but added, “If I had to think about it [concepts], I guess I could have.” One of the students from Focus Group 2 said that he did try to think about concepts during lab, but “everyone else [in his lab group] just wanted to get done”. Even though the students interviewed generally believed that they did not think about concepts during lab, the field observations suggested that this was not always the case. For example, at one point during the experiment, one particular lab group had formulated a hypothesis about the identities of their unknowns based on a comparison of TLC Rf values for the known and unknown compounds. Upon injecting each unknown into the GC, they actively debated when a peak should appear, rooted for the instrument to give them this peak, and were delighted when the peak appeared on the chromatogram as they had predicted. Thus, it seems unlikely that these students would have, or could have, made such predictions if they had not been using their conceptual understanding of GC. The students interviewed all felt rather differently about changes in their conceptual understanding after performing the experiment. Before the experiment, the student from Interview 1 questioned the practicality of IR, but was surprised to find IR “a lot simpler to use than descriptions made it seem”. The student from Interview 2 said that she had never heard of some of the instruments before, but now understood “why people might actually want to use these machines”. Focus Group 2 said that they now understood “how the graphs [spectra] are made and what they mean” and had a better understanding of “how equipment is used by scientists”. Focus Group 1 felt that the experiment did not change their


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conceptual understanding much— because “chromatography all works the same”; however, it was these same two students who reported that they had developed valuable, critical thinking skills during the experiment (vide supra). Summary of Findings In general, the students’ attitudes toward using instrumentation in the lab were quite positive. In particular, the students felt that using instrumentation in the lab allowed them not only to connect “chemistry” and the “real world”, but also to develop skills that would be valuable to them in the future. It is noteworthy too that the students studied here clearly preferred to use new equipment (or at least equipment that looked new), and to have a conceptual understanding of how a particular instrument functions before learning to use it. Students also preferred tools that were “simple”, but varied widely in their interpretation of what a “simple” tool was. How did students relate the underlying chemical concepts to the instrumentation? The students perceived that they were best able to relate the underlying chemical concepts to the instrumentation when they were provided with a detailed description of the instrument (i.e., before they used the instrument). Flash chromatography, IR, and GC were the instruments for which the students felt they had the best conceptual understanding and indeed these particular instruments were emphasized in lecture and laboratory. Even though some of the students were able to demonstrate some understanding while they were performing the experiment (vide supra), most of the students perceived that they seemed to develop such understanding during the preparation of the lab report (i.e., after the experiment was complete). How did working in a group affect student attitudes toward instrumentation, their understanding of instrumentation, and their understanding of the chemical concepts? The students generally felt that working in a group saved time, allowed them to complete complicated tasks much more efficiently, and provided opportunities for them to discuss ideas. One group even felt that learning to work in groups was a valuable skill learned from this experiment. Within the framework of the distributed cognition model, such aspects of group work would certainly be expected to foster construction of knowledge. Implications for Educators A judicious choice of the instrumentation and an appropriate experimental design are probably the two most important considerations for developing lab activities that utilize instrumentation. The students described here knew that GC, IR, TLC, and flash chromatography are all tools that are used by professional chemists and, as a consequence, this made them feel like they were using “real-world” tools. Students also clearly prefer to use modern or new equipment (if possible) even if old(er) equipment functions equally well. In this experiment, many of the students found the large number of TLC analyses tedious, which was exacerbated by their perceptions that the TLC analyses provided little information about the identities of their unknowns. Thus, the stu-

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dents’ impressions of TLC were generally not positive, even though their reasons for disliking TLC had little to do with TLC itself. The students had much more favorable impressions of other instruments (in particular, IR and GC), possibly because these instruments required a much smaller number of analyses or because these instruments were perceived to provide more useful information (than TLC). Clearly, it is important for students to make judgments about the value of an instrument or technique based on factors associated with the instrument or technique itself, rather than on factors associated with the experimental design. Finally, time-related issues were very important to the students—they neither liked wasted time (e.g., waiting in line for an instrument), nor insufficient time to complete their tasks. Group work did seem to reduce or alleviate time-related issues and, perhaps more importantly, it is an important aspect of learning, as indicated by both the student interviews and the distributed cognition model. However, the experimental design should include a consideration of how groups will be created, as well as the role(s) each student will play within a group. Although it might be desirable for students to form their own groups and assign roles, instructors should still monitor the group creation process to ensure healthy group dynamics. These factors have strong implications for the design of laboratory experiments that use modern instrumentation or techniques. First, the theory and purpose of these instruments or techniques should be discussed in lecture, and (if possible) the procedures used to operate these instruments should also be demonstrated in lecture or lab. Second, the design of the experiment should highlight the capabilities of the instrument or technique, not bog the student down in complex or timeconsuming repetitions. Third, the experiment should take full advantage of group interactions by strategically placed questions (postlab or during the experiment) that require students to predict and interpret the data collected with the tools. WSupplemental

Material

The complete lab experiment is available in this issue of JCE Online. Literature Cited 1. Nakhleh, M. B.; Kracjik, J. S. J. Res. Sci. Teach. 1993, 30, 1149. 2. Nakhleh, M. B.; Kracjik, J. S. J. Res. Sci. Teach. 1994, 31, 1077. 3. Eichinger, D. C.; Nakhleh, M. B.; Auberry, D. L. J. Computers Math. Sci. Teach. 2000, 19, 253. 4. Malina, E. G.; Nakhleh, M. B. J. Chem. Educ. 2003, 80, 691. 5. Distributed Cognitions: Psychological and Educational Considerations; Salomon, G., Ed.; Cambridge University Press: New York, 1993. 6. Abrams, C. IR Tutor; John Wiley & Sons, Inc.: New York, 1998. 7. March, J. L.; Moore, J. W.; Jacobsen, J. J. J. Chem. Educ. 2000, 77, 423. 8. Still, W. C.; Kahn, M.; Mitra, A. J. Org. Chem. 1978, 43, 2923. 9. Nash, J. J.; Meyer, J. A.; Everson, B. J. Chem. Educ. 2001, 78, 364.


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Students' Attitudes toward and Conceptual Understanding of Chemical

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