Olaf Runauist Homline University St. Paul, Minnesota 55101
I
Programmed Laboratory An audio-tutorial approach to elementary organic laboratory
During the past two years, we have been experimenting with various teaching techniques and their applicability to college chemistry lectures and laboratory. This paper describes an approach we have found very eflicient and effective in teaching organic laboratory procedures and correlating laboratory work. To illustrate how we have used the audio-tutorial approach, a single organic laboratory period (3-3'/% hr) will be described in some detail. For the laboratory class of 24 students, a single tape recorder was used, and it was assumed that students had no previous knowledge of the reaction or procedures to be studied. The tape played continuously during the laboratory period and was constructed so that students had time to carry out procedures after directions were given. At the beginning of the period, the tape announced the procedure to be studied or reaction to be demonstrated (i.e., "oxidation of aromatic side chains"). The reagents and quantities were given along with the procedure (i.e., "reflux the mixture for 60 min"). During the ensuing 10-15 min, students weighed out reagents, set up apparatus, and recorded data in their laboratory books. During this time a balanced equation of the reaction was projected, and the tape asked a series of questions about limiting reagents, quantity of product expected, lahoratory setups, safety, etc. The instructions, questions, and comments given during the weighing and setup period were repeated several times, thus allowing students to proceed with laboratory work and listen in spare moments. After the weighing period, the tape reviewed the reaction conditions and directed the students to commence the reaction. During the 60 min reflux period, directions for and explanations of the work-up procedure were given. During this period the tape also gave a lecture about oxidation of aromatic side chains with frequent reference to the specific reaction being carried out by the student. An overhead projector was used in conjunction with this taped lecture. During the period when the product from the reaction mas being worked up, the tape reminded students of the procedure and made suggestions on laboratory techniques. While the final product from the reaction was being recrystallized, the tape and the overhead
projector presented some structure proof problen~s which involved oxidative degradation. The audio-tutorial techniques have been applied to a variety of diierent types of organic laboratories: Cheek-in (including a discussion on the use of certain equipment, how to clean equipment, and safety). Use of standard taper equipment (practice in setting up glass ware to carry out vsrious procedures). Solubility characteristics of compounds (the relative solubilities of 13 compounds in four solvents systems were determined; the tape ga.ve direotions and discussed solution theory). Extraction, crystallization, steam distillation. Synthesis (the instructions given for the first synthesis were detailed, hut for each succeeding synthesis fewer details were given). TLC (Students prepared plates and attempted sepmtrations of mixtures with various solvents. The lecture given by the tape was on spreading, developing, visualizing techniques types of absorbents and solvents, and preparative TLC). Qualitative analysis (a series of qualitative tests on a number of different compounds with a short lecture by the tape on the value, limitations, and theory of each test).
There are many attractive features about the programmed laboratory as described. (1) Most of the details connected with any laboratory procedure can he presented at a time when students are most receptive. (2) The lecture about a particular reaction or procedure can be given when a concrete example is before the students, and the lecture is given during laboratory time that is often wasted. (3) The tape can pace the students and encourage them to make the best use of their limited time. (4) The instructions given by tape can become less and less detailed as the laboratory course proceeds thus forcing the students to become more and more independent. (5) The laboratory instructor is freed from many of the small details involved in laboratory instruction and can concentrate on helping individual students. (6) Considerable time can be saved by eliminating pre-lab periods, by transferring the discussion of certain reactions from the lecture to the laboratory, and by helping students budget laboratory time. While the programmed laboratory is very useful in teaching techniques and procedures, we feel that the creative aspects of a laboratory course must he developed by other means. We wish to acknowledge the financial support of the Louis W. & Maud Hill Family Foundation.
Volume 44, Number
7, July 1967
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407
