Chemical Education Today
edited by
curricular change digests
Baird W. Lloyd Miami University Middletown Middletown, OH 45042
Scientific Communication and the Unified Laboratory Sequence1
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Todd P. Silverstein, Norman J. Hudak, Frances H. Chapple, David E. Goodney, Christina P. Brink, Joyce P. Whitehead Chemistry Department, Willamette University, Salem, OR 97301 The Unified Laboratory We have been teaching a sequence of Unified Laboratory courses (1) at Willamette University since 1982. These courses introduce students to (i) modern laboratory methods and instrumentation, (ii) the relationship between theory and experiment, and (iii) the use of creative thinking in problem solving (2–5). Recent events have convinced us to revise these courses substantially. In this revision we introduce new techniques such as molecular modeling, and we also expand our students’ repertoire of scientific communication beyond the simple laboratory report. The Unified Laboratory sequence has replaced all laboratories in our physical, inorganic, and analytical chemistry and biochemistry courses (1–5). Students generally begin the four-semester sequence as second-semester sophomores. Typically 12 to 16 students are enrolled in each of the courses in the sequence. Two courses (I & III or II & IV) are taught every semester. Unified Laboratory projects feature several different analytical techniques as well as distinct combinations of physical, organic, or inorganic chemical concepts (see Table 1; for further details, see JCE: Online version1). Projects last 3–8 weeks and typically feature teams of 2 or 3 students. The number of students working during any of the the 3-hour time blocks supervised by faculty varies from week to week, but ranges from 2 to 8. Students analyze their data individually and draft their own discussion of results. Student laboratory reports also include a photocopy of the laboratory notebook, pertinent spectra, plots, and data tables. Revisions to the Unified Laboratory Program: New Projects Table 1 lists the revised schedule of Unified Laboratory experiments. Of the twelve projects, three have been developed since the inception of the program (1). The “Temperature Dependent Relaxation Kinetics” lab was first implemented in 1987; it uses stopped-flow pH jump techniques to determine rate constants and activation parameters (∆H‡, ∆S‡, ∆G‡) for a reaction mechanism. Two new experiments (Monoamine Oxidase, and Molecular Modeling) will be implemented in the fall of 1997. The “Monoamine Oxidase” project uses chromatography and spectrophotometry to purify and characterize the enzyme. Subsequent photometric assays explore the enzyme’s substrate specificity, activation energy, and denaturation. Finally, in the “Molecular Modeling” project, students characterize enzyme–substrate and drug–receptor interactions. Energy minimization protocols are used to make predictions about protein structure and ligand binding, and to explore pharmacological and biomedical implications. With these additions, the twelve Unified Laboratory projects introduce
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our chemistry majors to nearly all of the instrumental methods commonly encountered in modern chemistry. Modes of Scientific Discourse in the Unified Laboratory In addition to expanding student exposure to instrumentation, we have focused the current revision on modes of discourse in the field of chemistry. In 1995 the Willamette University faculty adopted a “Writing Across the Disciplines” program that replaces the standard freshman English composition course with a series of “writing-centered” courses. Writing-centered courses must stress (i) the importance of revision and editing, (ii) the differences be…the twelve Unified tween informal “private” writing (which helps the Laboratory projects writer to develop thoughts) introduce our and formal “public” writing (used primarily to commu- chemistry majors to nicate with others), and nearly all of the (iii) the aspects of writing that are unique to specific instrumental methods disciplines. We determined commonly encountered that the Unified Laboratory program was a perfect in modern chemistry. place to incorporate “writing-centeredness” into our chemistry curriculum. We began the revision process by enumerating the critical modes of communication in chemistry: • • • • • • • •
keeping a laboratory notebook writing a formal laboratory report reading and searching the scientific literature writing a short technical report writing a research proposal preparing a research poster giving an oral presentation writing a research article for publication (including abstract, introduction, methods, results, discussion, and references)
We then chose one laboratory project each semester in which to introduce one or more of these modes of discourse (see Table 1). The Carvone laboratory in Unified I has been expanded to include a brief library research project and a short technical report. In this exercise, students explore secondary library resources such as the Dictionary of Organic Compounds, the Merck Index, Chemical Abstracts, and the Science Citation Index. They are asked to prepare a one- or two-page report on the synthesis and characterization of a specific compound assigned by the instructor. In Unified II, the new Molecular Modeling project
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Chemical Education Today
will conclude with a poster session rather than with a typical laboratory report. The poster format fits logically with this project, since “experiments” will be carried out using computer modeling and the use of laboratory notebooks is likely to be minimal. This project lends itself quite naturally to the visual nature of the research poster presentation. Upon concluding the “Silver Acetate Ksp ” project in Unified III, students will submit both the usual photocopy of the laboratory notebook and a formal report set in research article format. In preparing this formal report, students will consult with faculty and other readers at several stages in the writing process (e.g., outline, rough draft, final draft). The second project in Unified IV is the student Research Proposal. This project must be original, experi-
mentally feasible, and publishable. The proposal is three to five pages long (double-spaced) and fully referenced; it is graded for both content and composition. Faculty consultation at the outline, rough draft, and final draft stages is integral to the writing process. Upon completing the research proposal, students give a 15–20-minute oral report summarizing key aspects of their projects. All of our chemistry majors are required to complete a senior research experience, which concludes with both an oral presentation and a senior thesis. The written thesis is a research paper in a format suitable for publication in a refereed scientific journal. The oral presentation is similar to one that could be given at a scientific meeting. Although we entered into this revision process with some trepidation, we are pleased with the outcome. Our
Table 1. Unified Laboratory Projects Title
Techniques
Concepts
Unified Laboratory I: Molecular Structure and Physical Properties Carvone in Natural Oils
[±][Co(en)3]I3 Complexes
Ring Strain and pKa of Cyclic Carboxylic Acids
vacuum distillation spectroscopy literature search synthesis, purification spectroscopy magnetic susceptibility bomb calorimetry pH titration
natural products separation product characterization short technical report a racemization crystal field theory paramagnetism Hess's law, bond energies, ring strain Gran plot and pK a
Unified Laboratory II: Natural Products Monoamine Oxidase: Purification and Characterization Molecular Modeling: Ligand–Receptor Interactions Copper and Iron in Spinach
column chromatography SDS-PAGE HPLC spectrophotometry molecular modeling energy minimization
microwave digestion AA spectroscopy
protein purification enzyme kinetics protein denaturation molecular interaction surfaces intermolecular forces agonists, antagonists, and drug effects poster session report a preparation of biological samples analytical sampling techniques
Unified Laboratory III: Chemical Equilibrium and Energetics Solubility Product of Silver Acetate Copper(II)–Amine Complexes Toluene–Cyclohexane Liquid–Vapor Phase Diagram
radioactive synthesis ion-specific electrodes scintillation counting spectrophotometry polarography solution calorimetry macro-scale distillation gas chromatography
Nernst equation ionic strength, activity coefficients formal edited reporta E , E 1/2, and n (oxidation state and Keq ) ∆H °, ∆S °, ∆G °, Keq chelate effect, denticity, and ∆S ° phase diagram Raoult's law, Clausius–Clapeyron equation gas phase activity coefficients
Unified Laboratory IV: Advanced Experimental Techniques Temperature-Dependent Relaxation Kinetics for MonoacetohydroxamatoIron(III) Research Proposal Spectroscopy of Diatomic Molecules aThese
stopped-flow kinetics spectrophotometry ion exchange column titration, pH, and redox problem identification literature search high-vacuum synthesis spectroscopy
temperature dependence of kinetics confirmation of reaction mechanism from the literature Eyring equation: ∆H‡ and ∆S‡ drafting a research proposal a envisioning data analysis bond dynamics, isotope effect following literature protocols
activities have been added to school students in the various modes of communication in chemistry.
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curricular change digests graduates consistently report back that the single most important part of their preparation for success in chemical research was their experience in Unified Laboratory. Now we hope to expand this record of success by incorporating into these courses exposure to the important modes of communication in chemistry. Furthermore, this new emphasis allows students to experience how chemists use writing to do chemistry—to pose and to think through the kinds of questions that chemists encounter. As the program unfolds over the next three years, we will report on student response to the changes, as well as faculty assessment of the outcome of the reform. Note 1. The complete text of this report may be found in JCE Online, http://jchemed.chem.wisc.edu/.
Literature Cited 1. Goodney, D. E.; Hudak, N. J.; Chapple, F. H.; Brink, C. P. J. Chem. Educ. 1986, 63, 703–706. 2. Silverstein, T. P.; Hudak, N. J. CUR Q. 1994, 14(3), 127–130. 3. McMinn, D. G.; Nakamaye, K. L.; Smieja, J. A. J. Chem. Educ. 1994, 71, 755–758. 4. Cartwright, H. M. J. Chem. Educ. 1980, 57, 309–311. 5. Bailey, R. A.; Zubrick, J. W. J. Chem. Educ. 1981, 58, 368.
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