In the Laboratory
Projects in the Physical Chemistry Laboratory: Letting the Students Choose Paul D. Buckley and Kenneth W. Jolley Department of Chemistry, Massey University, Palmerston North, New Zealand Ian D. Watson Principal’s Office, Massey University, Albany Campus, Auckland, New Zealand For many years the 12-week (24 laboratory sessions) Physical Chemistry Laboratory course at Massey University consisted of a series of set experiments. Although admirable in their way, these encouraged students to view physical chemistry as a dull repetition of known procedures (1). If the experiments “did not work” it was all too easy to blame the equipment, the technician, the demonstrator, or the instructions. This was frustrating, because science above all else should be about the excitement of solving problems. As others (2–4) have done before, we decided to try to change the students’ attitudes to problem solving and to science, by introducing projects. Given limited equipment and a small budget, it was tempting to prepare a list of acceptable projects and ask the students to choose, but this seemed little different from selecting a rotation experiment. Assigning the undergraduate students to projects in physical chemistry research laboratories is also not practicable at Massey University, even though this is a successful strategy adopted by larger universities. Letting the Students Choose The solution was simple but effective. Let the students choose any project that interests them. The project, however, must be based on a physical chemistry paper in the literature and must be done with resources available in the department. Several advantages ensue. First, since the students make the choice, they make a commitment to the project. It does not matter whether the choice is primarily based on interest or on expediency, the final responsibility still rests with the student. Second, working within a budget and negotiating access to available equipment gives practice in skills that are often as important to the scientist as actually doing the experiments. Third, since the chosen project is new to student and demonstrator alike, there is no question of transferring blame if unexpected results are obtained. Choosing the Project The choice of a physical chemistry project is raised with the class at the start of the course. Students, often for the first time in their university career, are faced with the question of what they want to do. Choosing is not always easy. To help in selecting, a list of possible starting points is provided. It is suggested that they find an article of interest in a chemistry journal or an experiment in a chemistry laboratory manual and attempt to duplicate it. Or choose a particular technique such as NMR or infrared spectroscopy and search for an application. Or take a particular reaction and study it in a variety of ways, such as by making equilibrium and kinetic measurements. When the projects were first introduced 10 years ago, choices that were entirely research based in the sense that the outcomes were unknown were allowed, but this was dis-
continued for two reasons. First, when students are making their first forays into the unknown it is helpful to both the student and the instructor to know that a specific result is possible; otherwise it is never clear whether it is the inadequate technique of the student or the impossibility of the project that is limiting progress. Second, it is too demanding on the demonstrator’s time to be supervising a number of open-ended experiments simultaneously. The projects now begin, therefore, with the aim of repeating a specific measurement reported in the literature. The physical chemistry experiments in this Journal are an excellent resource and are commonly used. Only after successfully completing measurements reported in an article is the project opened out by attempting new measurements on the same chemical system or using the same technique for studies of other systems. After making a tentative choice the students prepare a list of chemicals and equipment they need and discuss the feasibility of the project with a demonstrator. The major part of the project must relate to some aspect of physical chemistry, but synthesis of starting materials is allowed. Any necessary chemicals may be ordered provided costs are not exorbitant. Some projects use equipment in the research laboratories. However, if the resources needed are not available or cannot be supplied, another project must be found. The motives for the final choice are as varied as the students. Some find project work in an area that has always fascinated them. Some make a pragmatic choice based on what seems manageable and likely to lead to the maximum chance of success. For some the experience is so new and so challenging that they procrastinate and need further help and suggestions before finally making a choice. Carrying out the Project in the Laboratory The students usually work in pairs. This has the advantage of reducing the workload on the technicians and demonstrators and also allows for creative cooperation between the students. We have found that it is important to clearly explain to the class why the project work is included in the course. If the new skills required are not understood, and if the value of these skills is not recognized, the project work may be treated as just another barrier placed in the path of the students as they progress through a degree. For example, to encourage a positive attitude toward problem solving, the section in the book Zen and the Art of Motor Cycle Maintenance (5), in which the repair of a motor cycle is blocked by the sheering of a screw on the manifold cover, is described as an illustration of how importance must be given to what may at first seem an insignificant problem (namely the removal of the screw) if the overall aim (repairing the motor bike) is to be achieved. Confidence grows when a problem that at first sight seems impossible is overcome after some effort. To share the
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In the Laboratory experience of problem solving as widely as possible, a brief meeting is held at the start of the first laboratory session each week in which the particular problems holding up progress on each project are identified. In the subsequent week, the class can examine how the problem has been surmounted or circumvented. The class needs to be reminded that the solution to any problem can appear obvious in hindsight and not to be embarrassed when describing the resolution of the previous week’s difficulty, no matter how trivial the solution seems. The introduction of project work is also used to give students the opportunity to make oral presentations of their work and to defend their ideas at a seminar. One student from each pair near the beginning of the laboratory course presents the plan for the project, explains the choice, and discusses likely problems. The second student at the end of the course presents the results, discusses the problems that have arisen, and describes any additional work that had been carried out. The talks typically last from 10 to 15 minutes. Questioning is encouraged by all students during and after the talk, but usually it is the demonstrators who ask most questions. Initially, little help was given in the preparation of the talks and the quality of the presentations was often uneven. We now include in the laboratory book general advice on how to prepare, practice, and deliver a short talk. Some students still find speaking to the class stressful. The rotation experiments have not been completely abandoned but now make up only about half of the course. They are carried out in the first weeks while equipment and chemicals are being assembled, and serve to give the student a sense of achievement before approaching the unknown territory of the project. As suggested by others (6), the students are also encouraged to explore even these rotation experiments.
of pleasure in their sense of achievement. Furthermore, although specific references were not available, investigations were made on topics such as how microwaves heat up materials, the effect of sulfate ion on the tanning process, and determination of the diffusion coefficient of polystyrene by intensity fluctuation spectroscopy. All students now have the experience of meeting problems that are new to the demonstrators and for which there are no quick-fix solutions given by the all-knowing supervisors. In fact, one major value of the project is that it is clear to the students that they usually have as much knowledge of their project as do the demonstrators and they cannot simply sit back and wait for the supervisor to solve the problem. Certainly not all students end up completely confident of their ability to overcome problems that arise in new situations. In each pair, one may become dominant and more confident than the other, although usually the work is well shared according to each student’s strengths and weaknesses. In our experience all students gain some insight into the joys and despair of scientific research. Student Response to the Projects Most students report finding the project exercise a rewarding and challenging experience, appreciating the reasons for doing it, and valuing the experience it provides for their future careers. Typical comments are: Initially I found the idea of a project like this intimidating and challenging but once into it, it was rewarding, enjoyable and satisfying. The satisfaction comes from having completed this on my own. We are satisfied to have overcome the problems and satisfactorily obtained data and graphs close to what was expected.
Comments on the Projects The type of project chosen has varied widely. Examples include a kinetic study on the inversion of sucrose (7), a thermodynamic study on the formation of the dimethylbenzamide–iodine addition compound (8), bomb calorimetry, the energy content of pizza (9), kinetic hydrogen isotope effects (10), kinetic study of adsorption processes in solution (11), structural parameters of methyl iodide by infrared spectroscopy (12), NMR studies of caesium chloride solutions (13, 14), thermodynamic and kinetic data for 2-methyl-2-nitrosopropane (15), the kinetics of oscillating reactions (16, 17), chemical storage of solar energy (18), and the Menschutkin reaction (19). By beginning with a specific starting point all students make progress on the project, even if all the projects are not completed according to plan. Each year many of the projects are also successfully extended. The practice the project gives in planning an experiment based on the succinct instructions provided in a journal article has proven invaluable. For example, on their first attempt some students prepare a solution, which must later be mixed with another, at exactly the final concentration that is required, making no allowance for the dilution that will occur on mixing. Occasionally the rules for selection described above have been waived because of the students’ enthusiasm for a particular topic. For example, soon after the discovery of the high-temperature superconductors, two students wanted to synthesize this material and make a few basic measurements. Even though the project involved rather more synthetic than physical chemistry, we supported the choice. The students were successful and gained a great deal
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While some parts of this project were tedious and repetitive, in general it was quite good fun and certainly a learning experience. We both learned a great deal about the subject of this project and about research work and problem solving.
As a result of working on the project some students for the first time seriously consider the possibility of graduate study. Perhaps the clearest indication of the success of the project work in physical chemistry has been the decision made by teaching staff in the organic and inorganic papers to include project work in their practical courses. The impetus for this change came, in part, from the enthusiasm of the physical chemistry students for their project work. Conclusion The laboratory course is now much more satisfying for both staff and students. Projects do demand more input from the demonstrators and require more effort by the technicians than is required for rotation experiments. We believe, however, that the benefits that accrue more than outweigh the extra effort. If large classes are to be run in the way described in this article, we recommend that they be broken into cohorts of no more than 16 to 20 people. Otherwise the time taken for the talks can become excessive, and it is more difficult for the students to effectively monitor progress in other student projects in the way described. On balance we can wholeheartedly recommend the exercise to others.
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