R. J. Palma, Sr. Midwestern University Wichita Falls, Texas 76308
A Technique Oriented Freshman Laboratory Program
A complete revision of the entire chemistry cumculum was initiated here in 1972-73. The first phase of the revisionam. . nmeram .~ was the freshman chemistm course. This course was a structured, classical program designed for chemistw and other science majors. The lecture oortion of the course was planned and redesigned according to a "Delayed Entrance-Keller Plan"1 format which began in the fall semester of 1973. The new laboratory program had been planned previously and started in the fall of 1972. The basic philosophy governing the new freshman laboratory program was that laboratory exercises were to be exclusively reserved for only those concepts and ideas which could not he taught more effectively by other pedagogical techniques such as demonstrations, slide-tape miniprograms, films, C.A.I., programmed learning booklets, etc. It was felt that laboratory time was too precious to be spent on teaching chemical concepts that could be presented just as effectively by other learning techniques. Application of this basic premise to our classical laboratory program resulted in the rejection of many popular and motivating experiments in thermodynamics, kinetics, and the measurement and observation of chemical and physical properties of chemical systems. For example, the measurement of enthalpies by using crude calorimeters, or the visual determination of rate laws and activation energies, are interesting and illustrative to a student studying simple thermodynamics or kinetics in the lecture, but these topics can he just as vividly illustrated by a live demonstration or film in lecture, and the student will probably observe a better experiment than he could have performed himself. The data from this experiment can he then collected by the student and analyzed if desired. Certainly, the student learns no useful laboratom techniaue or nrocedure by using the elementary and crude measuring systems that are usually dictated in many larce . freshman laboratories due to budgetary restrictions. We found that rigid, and sometimes painful, application of our criterion rendered an almost exclusively technique oriented program for the freshman level. It seemed evident to us that you could show a student a film on the use of potentiometric techniques, present him with programmed books on the topic, give lectures and demonstrations on this topic, etc., hut until the student has actually used these instruments, and in addition, understood and evaluated their accuracy, precision, limitations, utility, and care, he could never be judged competent in this technique. It was realized that if these techniques were taught thoroughly and completely with the best available equipment, then it would be unnecessary to reteach them in a proper fashion in subsequent courses, (as is usually the case). Thus, a student armed with the pmper knowledge of these basic tools could use them in relevant applications in future courses in the study of chemical systems, in addition to learning genuinely new techniques. In order for this type of laboratory program to he feasible, it was necessary not to predicate the exercises on 'A twa-tracked oroerarn. with rnultiole entrance and crossover times, that uses a modified Keller Plan. *Brooks,D. W., J. CHEM. EDUC., J7,62 (1970). 116
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material presented in the lecture. The laboratory and lecture were to he separated formally, and in reality. Material necessary for comprehension of the exercise was taught in depth prior to the lab by video taped lecture-demonstrations and slide-tape minicourses or literature. The T.V. video tapes were prepared by that member of the staff having the greatest experience and expertise in the technique. Students were commonly shown several alternate methods of performing the technique and as much current "state of the art" as was feasible. Students took a prelaboratory examination which qualified them to attempt the exercises. The laboratory logistics were based on the popular modular system, wherein each student checks out the module containing the necessary laboratory and/or study equipment necessary for the exercise. The reported monetary' efficiencyz of the modular system proved to be phenomenal in our case. Over a two-year period, we were able to make available to a very large number of freshman students some rather expensive equipment and instruments, and yet decrease the operating cost per student by 20%. In order that each technique was taught in a complete manner so that no reteaching was needed, it was necessary to purchase first class equipment. The modular approach made this economically feasible. Those simple techniques which we felt could be taught thoroughly at the freshman level were: acid-base, redox, complexometric and potentiometric titrimetric analysis, solvent extraction, solid-liquid chromatography, paper chromatography, simple and fractional distillation, vacuum distillation, recrystallization, gravimetric analysis, determination of melting points and boiling points, potentiometry, spectrophotometry, conductimetry, constant current coulometric titrimetry, and selective separation by precipitation. An early laboratory exercise in statistics was added to allow the student to employ statistical tests to evaluate his data throughout the year. Students who had demonstrated proficiency in a specific exercise were allowed to waive that exercise. Students who demonstrated proficiency in three or more exercises were assigned to work with a senior chemistry major in a joint senior-freshman project. The freshman was evaluated by the senior at the end of the project and a formal evaluation was rendered. A simple organic synthesis (aspirin) and inorganic synthesis (trans-[Co(en)zClz]C1) were also added to provide color to what appeared to be a rather effective, hut otherwise drab laboratory program. However, student questionnaires showed that these two experiments were not significantly more popular than the others, and these "motivational" exercises will be replaced. The results of the program a t the end of the first two years were mixed. Most instructors did not provide the necessary illustrative and concept reinforcement material in lecture with sufficient demonstrations and audio-visual techniques to take up the slack caused by the lab reorganization. Student criticisms through the questionnaires and verbal feedback centered on the apparent sterility of the program, the difficulty of the exercises, and the usual disorganization inherent in many curricular revisions. The faculty were generally impressed with the results of the
pmgram. They indicated that these students displayed unusual laboratory sophistication and competence in their subsequent courses. The greatest compliment came from the lab assistants and other upper classmen who had taken the classical laboratory program. Nearly all indicated that they wished they could have taken this new lah program and several even requested to audit it.
Future changes include introduction of more chemically interesting compounds into the modules to increase their motivational aspect, while maintaining the integrity of the goals of the exercise; and synchronization of several modules into a unit to offer greater continuity and develop alternate technique modules for students who have demonstrated proficiency and do not select, or are not eligible for the senior-freshman project.
Volume 52. Number 2, February 1975
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