Arthur W. Varnes Standard O ~Company I of Ohio and David E. Wetmore' St. Andrews Presbyterian College Laurinburg. North Carolina 28352
A Novel Communicati0n~-Skik-Based Approach t0 the hstrumental Laboratory
Two common shortcomings noted hy employers of baccalaureate kvel chemists are their failure to write dear, roncise reports and weakness in utilization of chemical litera~ure.~-"n response to these criticisms, we have designed the St. Andrews introductory-year lahoratory curriculum in an attempt to foster development of those skills. Three goals were defined for the new course of instruction. First, the evaluation of laboratory performance must stress the importance of good writing style in laboratory reports. Second, the students must gain proficiency in utilization of several major instruments. Third, the students must become familiar with a portion of the basic chemical literature. The curriculum of experimentation which was adopted is summarized in Table 1. The students, in pairs, were allowed t o perform the experiments in any order they devised, subject to the constraint that no more than three pairs could utilize the same instrument during any twoweek period. The first week of the term was devoted to an explanation of the system, choice of laboratory partners, and scheduling.experimentation. Durina the second week . students were given audiovisual or writt;n material relative to their experiment and checked out by a student assistant on the appropriate instrument. Each assistant (a junior or senior chemistry maior) was responsible for a sinele instrument and was free to schedule-instruction periohs a t any mutually acceptable hour. This option relieved crowding during the regular three-hour weekly lab period. In addition to releasing the faculty from repetitive instruction, we felt that the assistants would learn much from answering students' questions and that the underclassmen would henefit from interactine with our better maiors. Students nerformed the actual experiment during tl;e third week. ?he initial set of laboratorv reDorts was due Fridav of the third week. The two-week cycie of checkout, experimentation, and report was repeated until all experiments were comnlete. r ~ - - - . Reports were to be written as if for publication in an American Chemical Society journal. T o emphasize the importance of communications skills, the evaluation was based 60% on format, grammar, andstyle, 30% on content, especially interpretation of results, and only 10%on quality of data obtained. Each student was required to submit his own report; collaboration on calculations was encouraged, but students were to devise the format of their papers and interpret the results independently. Students were not allowed to utilize prior reports prepared by their classmates. Much effort was expended on evaluation of the reports, as students were unfamiliar with the subtle points of scientific writing. After the first set of reports had been evaluated, a list of prevalent errors was compiled and submitted to the students. After completion of the laboratory phase, the remaining two weeks of the term were devoted to a literature project. The students were assigned a topic from the list found in
'Towhom r v r n m u n i r n t i u n i should he nddrrvird 'rikolnik. H J. CIIEhl. E1)UC.. 4s. iCC, 11971I 'Kdenhmnder, H. 51.. J. C H E M EDL'C.. iR."r)O 11971r %ossiter,B. W., J. CHEM. EDUC., 49,388 (1972):
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Table 1.
Laboratory Experiments
lnsfrumenf
Experimenfs Separate an ewal-volume mixture of ben-
Distillation
".
UV-Visible Soectrophotometry
I R Spectrophotometry
Gas Chromatography
N M R Spectrometry
graph, head temb.. pot tkmp.. refractive index, versus sample no. 1) D e t e r m i n e p K of an acid-bare indicator. -, 21 Determinevalidity o f Beer'r law for rolutionr of Cr(N0,13. C O I N O S ) ~and . a mixture of both. 11 compare K B pellet ~ and ~ u j o MUII l techniques for studying benroic aica.
-. -,
2 ) Determine similarities and differences in bonding in K,Cr 0 and K CrO,. I I Determine nature a d slgniiicaice or differencer in composition o f several brands o f gasoline, or 21 Prepare an aleotroPe and demonstrate its IeParabilitY; verify % comporition o f mixture, or 3) Determine identity and % comporition of the major components of cigarette lighter fluid. 1 ) netermine "J" coupling constants for several simple compounds, or 2 ) Demonstrate effects of hydrogen bondinq by commrison of several acetic acid-water ryrtemr t o acetic aciacarbon tetrachloride systems, or 3 ) Study of proton exchange between water and acetic acid.
Table 2.
Librarv Praieets
.... . .. ... . .... . . Differentiation of ketone, alden ~ d e ester, , and acid carbonyll Differentiation of conjugated. nanconiusatea and aromatic oi system; Extent of keto-en01 t a u t o m e r i m Dipole moment
Rater o f fast reactions Rates of inversion Resolution of enantiomerr Surface tension vis~osity
Table 2. They were asked to utilize the literature to find three independent experimental methods for determining the parameter in question. Students were to describe the apparatus required for each type of determination and to include a general description of experimental details. The literature was divided into three classes-Class I, laboratory manuals and textbooks; Class 11, monographs and treatises; and Class 111, journals. Students were required to include at least one reference from each class. After compiling their three methods, students were further required to evaluate and compare them. Useful criteria included precision and accuracy, time and expense required, and useful range of the method. The students' reactions to the course were generally quite favorable; no unfavorable overall ratings were forthcoming and the class was about equally divided among "good," "excellent," and "outstanding." Two criticisms were noted by a significant number of students, however. First, some felt that the reports required excessive time for Volume 52, Number 12 December 1975 / 801
proper preparation. Second, some experiments required extensive theoretical knowledge of topics not yet encountered in the lecture sequence. The faculty was also well-pleased with the results of this approach. Only two students failed to complete the sequence, a significant improvement over previous years. While the initial set of reports resulted in a mean grade of 60%, the final group received a mean grade of 85%, with a median of 90%. The library project was even more gratifvioe: some students who failed to oass the course achieved ';A"kades on this assignment. W; found no evidence that the decreased emphasis on quality of data in reaching the
802 / Journal of Chemical Education
report grade gave rise to shoddy performance. In response to student comment and our own ohservations, we are contemplating the following modifications. First, we plan to cut the number of reports from five to three, merely collecting notehooks a t the alternate times. This change will encourage students to continue their proficiency in notebook preparation. I t will also allow the students more time to consider comments on their initial report in preparing subsequent efforts. Second, we plan to review the content of specific experiments in an attempt to eliminate insofar as possible, those experiments requiring excessive amounts of unfamiliar material.
