David W. Brooks
Texas A&M University College Station, Texas 77843
I
The Station System
Enrollment in first year college chemistry a t universities throughout the nation far exceeds conferral of Bachelor degree majors. This reflects the simple fact that, by in large, first year chemistry is a "service" course. Educators are faced with serious problems concerning the role and conduct of laboratory work in first year programs. At many institutions, particularly large ones with sizable freshman classes, the problems of laboratory instruction are awesome. Many educators feel that laboratory work in such service programs is not essential and have recommended either abolition of this work or "dry-laboratories" in the form of lecture demonstrations including devices such as computer generated synthetic data provided for manipulation by each individual student. An impressive program has been developed a t Michigan State University.'r2 At Texas A&M University we are attempting to keep all of our demonstration work within the lecture program, and keep a full semester of active laboratory work. The problems existing at Texas A&M University are among those most commonly encountered around the country: burgeoning enrollments, limited space, increasing overhead costs, and a finite supply of teaching assistants. We have had little difficulty in devising suitable experiments, and, as with most programs, continuous active debate by faculty insures a dynamism of experimentation. Changes are introduced annually. Thus far we have succeeded in attracting reasonably good undergraduate students and sufficient numbers of good quality graduate students to assist in undergraduate education. Our recent efforts have therefore been intensely concerned with the difficult mechanical and logistical problems involved in the support of a large laboratory program. I n order to accommodate the number of students, minimize space and cost requirements, and more effectively utilize our teaching personnel, we first considered the large scale adoption of an audio-tutorial laboratory program. Early work in this teaching technique has produced exciting result^.^ However, the direct change-over from a completely conventional instructional program to an audio-tutorial program is fraught with many difficulties. First, there is the problem of high initial investment in equipment and renovations. Because of this investment renovations become essentially irreversible. Second are the problems of operating such laboratories for 2000 students on an unscheduled, open-ended basis. Teaching
assistants must be completely retrained; it is not possible to rely on their past experience. Furthermore, to be efficient, the change-over must be an all inclusive, one-shot affair. Finally, students must be acclimated to a new system. (i.e., Freshmen cannot he advised by upper-classmen.) Thus far we have been unable to effect a change-over to a complete audio-tutorial system, primarily because of the size of our program. Careful study of audio-tutorial laboratory systems has led us to believe that certain logistical elements may be adaptable as methods of operation. These changes have proven to be extremely effective and economical. All of the criteria we can use to judge student laboratory performance, under this system, indicate that such performance is every bit as good (measurably better in some instances) as under our previous conventional system. Finally, and perhaps surprisingly, the system was extremely well received by our student body as a whole. The primary reason for reporting our experience is that the program, in addition to being significantly more economical and effective, is one which has been conveniently implemented with our large groups of students. We call this program the station system. Preliminary Work
I n the years immediately prior to the development of this program all lahoratory experiments had been redesigned, and based upon a popular lahoratory manual. Two experiments were changed as a result of normal evolution. All experiments were checked. Minor modifications in both equipment and technique were noted. I n the registration procedure, students were enrolled in groups of 25. These eventually were assigned to a particular lecturer (who taught about ten such sections in a large lecture hall), a laboratory supervisor (who supervised pre-laboratory instruction to six sections in a large lecture hall), and a graduate teaching assistant who directly supervised laboratory work. The lahoratory areas were set up to accommodate 26 students. Each area was divided into 25 stations. A station consisted of t,wo numbered, empt,y, unlocked drawers. A single pan student balance was assigned to each station based on convenient access to that station. Master locator sheets were prepared indicating the number of the station drawers and the balance assigned to each station, five stations per balance. Immediately prior to the opening of the semester, a copy of the section roster of students' names was attached to a copy of ' BRUBAKCR, C. H., SCHWENDEMAN, R. H., AND MCQUARRIE, the appropriate station locator sheet and delivered to D. A., J. CHEM.EDUC.,41, 670 (1964). the graduate teaching assistant involved. I n addition, SCHWBNDEMXN, R. J., J. CHEM.EDUC.,45, 665 (1968). each teaching assistant was assigned to his own private I ~ B E LA. L , F., "Teaching Aids Programs," Advisory Council pair of locked drawers. on College Chemistry Newsletter, Serial Publication 28 (1967). 62 / Journal o f Chemical Education
Equipment
Every week each station area was used by t,en or more student sections. All of the required equipment for a given experiment was placed in one drawer. The second drawer was used by our stockroom staff to accomplish an equipment change-over. At the beginning of a new week, equipment from the preceding week was collected and replaced with that for the forthcoming week. (For the most part this procedure was smooth and efficient. The dramatic laboratory upheaval frequently encountered as equipment for different courses is interchanged between semesters was avoided .) General Operation
At designated class hours students would meet in the large lecture hall for pre-laboratory instruction. Large screen projection (10 X 14 ft) of video-taped material was used for this purpose.& The taped programs provided a brief explanation of the theory of each experiment, and included a demonstration of the apparatus and of data collection. Programs varied in length from 8 to 28 min. The first program, L'Introduction to Laboratory," was 38 min and offered a complete description of all aspects of the course, including the station system. During the first meeting, students were given a detailed hand-out which included all directions for laboratory operation. I n addition, this hand-out included a schedule of the dates on which experiments would be performed, and the dates on which laboratory reports were due. Instructions during the first session were limited to safety instruction, discussion of the station system, and detailed explanation of and practice with single pan balances. The same introductory tape, together with special written instructions describing how to deal with the special problems anticipated, was our primary introduction of our graduate teaching staff to the s y ~ t e m . ~ Monitoring Student Progress
Each student was required to keep a double-entry type research notebook. These notebooks provided a satisfactory means of evaluating the students' work. The report was submitted in three different parts. Part I. The first part (25%) included a write up of the Title, Purpose, Procedure, and Safety concerning any experiment. This was used as a prod to have students prepare in advance of the TV instruction. After TV instruction, there was a question period conducted by supervisors, and followed by a quiz. Part II. The students then proceeded to their laboratory stations and began work. During the TV instruction modifications of experiments were pointed out. Each station was provided with two lists: one describing all of the equip'BARNARD, W. I
