J. J. Lagowski The University of Texas Austin
Audio Aids in Laboratory Teaching
In many instances more individualized instruction than the conventional verbal or printed directions can be provided in the teaching of laboratory techniques. Very often the student does not receive the full benefit of a lecture discussion because be is too busy taking notes; a printed, abbreviated instruction sheet is usually an attempt to provide a more coherent set of directions. The use of such printed directions, however, invariably slows down the learning process because the student must constantly shift his attention from the printed sheet to the object he is studying. Little use has been made of audio tapes for operational instructions in the chemistry laboratory, but this medium can permit the student to look at the object he is studying and to have his hands free. During the past two years a t The University of Texas, we have been investigating the use of audio tapes for laboratory teaching in general chemistry. Two basic types of magnetic tape units are available. There are those that record on a roll of continuous tape and those that use a belt. The latter, used with a transcribing unit' employing a footswitch, is more versatile for laboratory instruction. The use of a magnetic recording medium has obvious advantages in terms of flexibility and recording or correction, and a belt of recorded information can be duplicated as many times as necessary. I n practice, we divided directions for use of a particular instrument into a series of short (15-30 sec) statements, each of which represented a complete unit of information. Each unit ended with an audible "click" indicating to the student that the directions were complete and that he should perform the operation described. The student could stop the tape at any point, of course, or could rerun any portion. Thus he could give greater attention to the operation he was performing. We employed this technique to present instructions to two erouws of 32 students on the use of an analvtical balance. T'he instructor discussed the general "characteristics and use of the balance before the class in the usual manner, but discouraged note taking. Then each student was shown how to load the belt, use the footswitch, and return the take-off head to any position on the tape, and was assigned to a balance which had a transcribing unit.
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' Although there are devices with
comparable specifications, have used the IBM 212 transcribing units because these were readily available looally in the quantity necessary to conduct comparative experiments. we
The results of these experiments are difficult to measure. However, there was general agreement among the instructors that this technique permitted a class to pass through the introductory phase of balance instruction in significantly less time and with better technique than when instruction was by the standard method. (Students filled out a questionnaire after the experiment.) The laboratory instructor was able, moreover, to direct his full attention to students with problems, and students were able to proceed at their own pace.
Student ming o tope recorder b r inrtructionr on t h e "re of on onolyticd balance.
The technique described here can be applied in a variety of ways, since it is ideally suited for individualized instruction. Thus, students who were absent when a laboratory technique was taught can be given a brief discussion of the subject and then allowed to use the equipment with a minimum of supervision. Recorded instructions can be used where extensive remedial work is necessary. In both these instances, the instructor would be free to devote himself mainly to the whole class. An obvious extension of this technique is in the routine instruction on the operation of instruments used, for example, in the instrumental or research laboratory. There individualized "check out" procedures very often involve an inordinate amount of an instructor's time. He could spend much of this time more advantageously in discussing with students the more important aspects in the use of these instruments.
Volume 43, Number 9, September 1966
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