provoccrtive opinion "You Don't Have to Think in Lab!'' A. L. Hanson St. Olaf College, Northfield. MN 55057
Students in the introductow chemistrv course often complain about lahoratory; if instructions are explicit, lab work is "cookbook" or trivial, and if experiments are open-ended or require student decisions, they are "vague and unclear." Most students say that laboratory and lecture do not correlate, and for a variety of reasons laboratory is judged to he a waste of time. Twical negative attitude toward lab surfaced one day as mycdleague~wasasked by a student to explain a reaction; he asked the student what he thought, to which the latter replied "But this is lab-you don't have to think in lab!" What is wrong with laboratory? For years we have insisted to our skeptical non-science colleagues that laboratory is essential to learning science and that it should have priority over conflicting football or band practice. Why don't our students see i t that way? In spite of many innovations-from making oxygen and nitric acid a half-century ago, t o using thick manuals with lots of blanks to fill, t o full afternoons of qualitative analysis (which many enjoyed hot often did not understand), to open-ended "Jay Young experiments" (which challenged some but baffled many), we have not convinced students that experiments are worthwhile. What do students expect of lab? Livant' reported typical student reaction: "I'd like to use my mind . . . instead of feeling drained. . . from five hours on my feet. . . .I'd like to feel invigorated, exhilarated, stimulated." This is an idealistic expectation which would he difficult to realize, but probably some specific complaints should he recognized and corrective steps taken. Following are a few suggestionsin response to complaints. (1) Laboratory seems so detached and it does not always synchronize with lecture. For various good reasons it is not always possible to get good match-up (e:g., dearth of good e x p e r i m & ~on atomic structure); if we take time toexplain these tothestudents they and accept the schedule. (2) may understand the There are difficulties with laboratory grading. Grades hased on laboraton, reoorts oenalii delinauent students hut do not differentiate among good students,as most of them do well. One solution is to hase a smaller part of the course grade on lab reports (15%is enough to insure that they will be turned in). then test the students' understandine of one or two expe&nents in every course examination. Pkkering and Goldstein2 showed statistically that a written test is a valid evaluation of experimental work. Mouts and Pickering3found that bonus credit provides good incentive for students t o turn in a complete set of reports. Special laboratory examinations or weekly post-experiment quizzes are other possibilities to focus
attention on knowine as well as doine: -. lab finals are demised . by students, however. (3) I,abora!ory work ic dull and hwing. Motivation ofstudents is the ohvinus kev to rood lahoratorv experience. As professional chemists m&y orus project from our own experience thrills of verification and discovery which just do not exist for uninformed and bewildered beginners. We must recognize the limited attention span of students, provide prepared materials to minimize distracting chores, and simplify procedures (ex., dropwise addition of reagents in plare of mime tedious and wasreful hulk measurements). In recent rxperiencr WP find toour surprisr that much ran be accomolished in a sinele two-hour lab. with better attention and leis fatigue. ~ o m e k x ~ e r i m e nare t s too long, tw detailed, and too demanding and thus defeat the nurDose . . of lahoratow for the beginnrr, viz., to give a meaningful discovery experirnre. Why weight to four decimal places? Why heat empty crucibles to constant weight? What is learned in the third and fourth reueated titration? Good terhniaue is of coursr essential foi the accomplished chemist, h u t a t the introductory level i t is more important to understand the relation than to gain the precision. Mindful that many students are incapable of Piagetian "formal operational" thinking, ways must he found to accommodate the abilities of the average students-many of whom, as reported by Pickering and Crahtree4 function by "dead reckoning," and for whom "just doing the measurements requires all available energy and attention." Laboratory offers a golden opportunity for meaningful conversation between teacher and student, in which the experiment can be made understandable and relevant. The bottom line is that students must be led to do more thinking and perhapsless doing. It is most discouraging to find that students can recall so little of what was done in lab one week ago. Pre- and post-testing may help, but mostly we must convey our conviction that laboratory is a discovery experience, not a routine chore. Some of our most promising ideas will fail to work in the laboratory; some students will successfully defy our attempts to w i d e and inspire. But if we simplif>;procedures, redure the amount of time spent in doing and put more emphasis on reflection and evaluation of results, perhaps we can reduce the number of students who believe "you don't have to think in lah." 'Livant, P., J. CHEM. EDUC., 52, 453 (1975). 2Pickering, M., and Goldstein, S. L., J. GHEM. EDUC., 54, 315
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3Pickering,M., J. CHEM. EDUC. 58, 43 (1981). 4Pickering. M., and Crabtree. R.. J. CHEM. EDUC. 56, 487 (1979).
Volume 59
Number 8
August 1982
671
