I: Laboratory Organization Chairman: Paul H. L. Walter, Skidmore College
Plenary Lecture: The Instructional Laboratory: Purposes and Organization Speaker: W. 1.Lippincott, University of Arizona The purposes of the undergraduate instructional lahoratory in chemistry well might he expressed as answers to the question: "What exactly do we wish students to learn in the laboratory?" Most answers probably fall into one of two categories. 1) Genernl Objectiues, such as: Students should acquire a feel for how chemical knowledge is obtained, and for how a
chemist thinks and works. This might include some sppreciation for the excitement of research, for understanding experimentation as an unfolding, open-ended, creative, and highly personal process, rather than a procedural regimen. It also might include a firm understanding of the underlying principles and logic patterns that make up the method of science. [Coyne,L., J. CHEM. EDUC., 51,447 (197411 2) Specific Objertioes, such as: They should learn some basic lahoratory skills and techniques; be able to adapt a skill learned in one context to another laboratory situation; he able to recognize the pieces of data that must be collected to solve a given experimental problem; design their own experimental approach in an attempt to obtain relevant data; be able to communicate adequately about the purpose, approach, results and dependability of the experiment. [Venkatachelam and Rudolph, J. CHEM. EDUC., 51.479 (191411 Nearly all current innovations directed toward meeting these objectives are centered on two approaches. First, getting students to discover that the method of science is exciting, challenging and intellectually rewarding; and second, finding ways of making the learning process easier and more palatable. The most successful specific programs appear to he those that (1) make students feel they are a part of a team working with a faculty member on a project he feels is professionally worthy; (2) make students feel they are attacking problems that affect the society at-large; (3) make students feel they are learning things that will help them help themselves find a place in the world and/or will help them help others. The organization of the instructional lahoratory varies widely dipending upon the lucal situation and s u c i ~things as the number and hackground of students, the a\,ailabd.tv of lahorar(rv i a c ~ l i t ~ eand s rearhlnr staff. and the funds available to p;ovide more than the hare necessities. Organizational patterns may be illustrated by five categories: (1) The traditional program where students are assigned to specific lahoratory sections that meet three to four hours a t a time for one to three times a week; experiments are assigned so most of the students are working on the same experiment a t the same time. (2) Self-paced organization in which the students have no set time to be in the lahoratory, but are given a series of experiments that must be completed by the semester's end, and are encouraged to move a t a pace that is cornfortahle for them in doing this; (3) Project-centered organization. Here, each student is given a project that involves a series of experiments and related techniques that will occupy his lahoratory time for a major portion of the term. He is encour~2
28
/
Journal of Chemical Education
aged to proceed more or less as an independent investigator; (4) Armchair experiments. Here the lahoratory is conducted in the lecture room. Each student is given a box about the size of a shoebox. This contains the chemicals and equipment needed to do the experiments. The student proceeds to do these as he sits in his seat. (5) Laboratory demonstration experiments. Here a demonstrator performs the experiments, and the students are asked to make observations and calculations based on what they have seen. In many chemistry departments, particularly those serving large nnmhers of students, the organizational pattern of the lahoratory may he dictated to a greater or lesser extent by one or more constraints, either imposed by the system, or desired by those responsible for conducting the lahoratory. Examples of constraint parameterr. that might control the organization are: logistics; availability of equipment; availability of audiovisuals; the kinds of experiments chosen; the instructional approach chosen, e.g., the project approach, self-paced, etc.; and the degree to which student development dominates the organizational pattern. All laboratory programs require pre-laboratory instruction of some type. This has traditionally been accomplished by lahoratory manuals reinforced by oral presentations by the lahoratory instructors. Now slide-tape presentations, films and television tapes, and even computer methods are used successfully for this purpose. The nature of the experiments or the experimental patterns used in the laboratories include: (1)The traditional exercise approach; (2) Approaches in which the students attempt to discover the concepts for themselves; (3) Individual student project or group contribution approaches. In the latter, each student contributes one or more pieces of data or observations to the solution of a group problem; (4) The student selection approach, where students choose whether they will pursue a given experiment in more depth or go on to try a new experiment and master a new technique. The philosophical models or patterns used in individual
experiments or in designing the lahoratory as a whole include the traditional observation-interpretation type of experiment: programs in which the student designs his own experiments; those in which technique and numerical
answers have primacy; others in which illustration of a principle or something judged to be highly relevant are featured; and the independent investigator pattern.
+
Contributed Papers Organization and Instruction in Large MultiSection Laboratory Courses
Wilbert Hutton, Iowa State University, Ames, Iowa Three different laboratory courses in general chemistry are taught at Iowa State University each quarter. These courses are presented in 15 different laboratories distrihuted over the four floors of the chemistry building. Frequently all three courses are taught simultaneously during a given 3-hour time period. Each laboratory accommodates 24 students and is in the charge of a graduate teaching assistant. About 2700 students are enrolled in these courses each quarter. Problems of an organizational and logistical nature and the high cost associated with what may a t first appear to be minor modifications of an experiment frequently become major factors to consider in such large programs of lahoratory instruction. Among those more unconventional procedures which have proven to he esneciallv helnful in managing these courses have been thk follo&ing:'~ssignrnents of students to work stations in the lahoratorv. so several students share the same eauipment rather than assigning to each student his own drawer or locker of equipment; the construction and extensive use of relatively inexpensive large scale units for preparing large quantities of reagent solutions; and the utilization of siphon assemblies, which connect automatic pipets, burets, and similar devices to carboys, as a means of dispensing solutions. As a supplement to the in-laboratory instruction given by graduate teaching assistants, extensive use is made of a n in-house closed circuit television studio. From this studio, one can broadcast color demonstrations of lab techniques, and professors in charge of as many a s 13 different courses can broadcast live and/or prepare and hroadcast videotape pre-lab and post-lab presentations into as many a s 15 different laboratories simultaneously.
A Laboratory Orientation Project-Chemical Literature and Reporting
G. G. Hickling, The University of Manitoba, Winnipeg, Canada Since many beginning university students are apprehensive about hoth the physical surroundings in which they find themselves and the academic expectations being placed upon them, we devote the first two laboratory periods to orientation and preparation for their chemistry course. After check-in and laboratory familiarization a Chemistry Achievement Test is written by the nearly 1200 students. This test, based on material with which most high school graduates should be familiar, enahles us to identify areas of weakness and thus provide remedial assistance most effectively. In the second period a n experiment entitled "Chemical Literature and Reporting" deals with library orientation and a description of scientific reporting techniques. Background information on mathematics, graphing, and experimental error is also included since this often proves to be a n area requiring upgrading. The video-taped television
tour of the lihrarv that accomuanles the exueriment. then the actual library assignment, acquaints kveryone with classification schemes, search techniques, etc.. and forces each student to learn how to use a lib;ary early in his university career. In addition, a problem assignment focusses attention on background material. This directed program enables students to get acquainted with the facilities, review background material, and start the program with the realization that a chemist's most important research tool is the recorded knowledge in a good library. Further information and tested material is available from the author.
The Use of Group Assignments in Chemistry Laboratory Programs
H. A. Neidig, Lebanon Valley College, Annuille, Pennsylvania In first- and second-year college chemistrv lahoratorv programs, group assignmentscan be used on occasion to advantaee in presenting hoth theoretical and uractical aspects ofinorganic and'organic chemistry. his approach involves having a group of students conduct a lahoratory investigation in which each student receives as an assignment a slightly different modification of a given experimental procedure. After completing the lahoratory work, the members of each group of students exchange data that then serve as a basis for the preparation of their written lahoratory reports and for discussion during the post-lahoratory session. Group assignments can be used with experiments that are presented to the students in a highly structured, detailed form as is done in a stoichiometric study of the lead(I1) nitrate-potassium halide-water system. However, this approach is even more effective when a group of students are asked to investigate the effect of structure on the formation of an ester which requires the students not only to select the specific chemical system to be studied but also to design the experimental procedure to be used.
An Intensive Quantitative Analysis Course
Forrest Frank, Dorothy Banfill and Frank Starkey, Illinois Wesleyan University, Bloomington, Illinois For nine years we have offered a four-week intensive experience in quantitative analysis lahoratory during the January term of a 4-1-4 school calendar with 8-20 stuVolume 52,Number 1. January 1975 /
29
dents per term. Prerequisites are two semesters of general chemistry and the first-semester lecture course in quantitative chemistry, although many students have also had one semester of organic chemistry. At least eight hours each day, five days a week are spent doing quantitative experiments which illustrate principles learned in the first-semester lecture course. The laboratory program begins with experiments done individually to emphasize and more rigorously develop standard volumetric techniques. Other experiments are performed, usually with a partner, for a total of ten experiments, including polarography, radioactivity, and visible or uv spectroscopy. Hopefully in three weeks the student is finished with these structured experiments leaving a week to devote to an independent project he has designed after consulting the literature. A final examination based on the experiments performed is about ten percent of the grade and covers basic principles, chemical equations, and handling of data. Grading of the unknowns includes a n option to repeat the experiment to achieve better results with a ten percent penalty and to correct a miscalculation for a five percent penalty. The absence of other courses competing for the student's time, the high grades (long hard work is rewarded with a n A grade), and the large amount of lab'space per student (other lab courses do not meet during January) are major reasons for this being a very popular course with students. It is a physically demanding course and requires much more time than other January term courses in the university but our students are proud of that fact.
Computer Management of Laboratory Courses
depat.tment frx that purpose. These cards are graded by faculty lahoratory assistants and by students under their direction. During the course of one semester, 800-1000 cards per week must he graded and some information given back to the student relating to his success or failure. To lighten the grading and "feed-hack load, we have written a comnuter oroeram ., in COBOL to both made the experimental results, including units and significant digits. and renort to the student his mistakes. Under the control of the master program, sub-programs will grade any mixture of different laboratory results requested. Class rolls are updated each semester from student computer cards generated by the registrar's office. Further faculty time savings are accomplished by having the students keypunch their own data cards.
Jak Eskinazi, Leslie N. Davis and Daniel J. Macero, Syracuse University, Syracuse, New York
Computer Assisted Laboratory Grading
Maximum utilization of teacher and student time, physical facilities, and equipment in a chemical instrumentation course has been achieved by employing the concept of computer management to coordinate computer assisted instruction (CAI), computer administered examinations (CAE), record keeping (grades), and scheduling use of equipment shared by the students. The CAI includes data handling programs and tutorial programs in electronics, gas chromatography, and spectroscopy. The computer administered examinations feature a self-evaluating curve with automatic updating, requiring no maintenance whatsoever on the part of the instructor. Modularization of the course topics means most students are doing something different from each other, but overlapping use of equipment is efficiently managed via computer reservation system. Interlinking of the various programs allows each student access to his own progress as well a s a means of comparison to the achievements of the rest of the class as a whole. As a result of being relieved of a good deal of organizational problems, the instructor is able to spend much of the class time giving virtually individualized instruction.
Computer Grading of Semi-Quantitative Laboratory Results
Kenneth L. Bridges and Denis M. Hyams, University of Southwestern Louisiana, Lafayette, Louisiana At the University of Southwestern Louisiana, the freshman chemistrv lahoratorv has evolved from an . exoerience . emphasis on demonstrations of abstract chemical phenomena and historicallv exneriments to one of . sienificant learning common lahoratory techniques and semi-quantitative analysis. Most of the assigned experiments involve the determination of an "unknown" with a subsequent report by the student on a 3 X 5 in. card provided by the 30
/ Journalof Chemical Education
.
John L. Deutsch, State University of New York, Geneseo, New York Six interactive programs have been developed to assist in the grading of the first semester freshman laboratory course (enrollment of 200-250). These programs were written in Basic and implemented on a remote teletype terminal hard wired to a Burroughs 3500 computer. The following experiments may he computer graded Density of an unknown liquid, including the calculation of standard deviation, 95% confidence interval, and precision (relativeerror oi the 95% confidence interval in pptl. 2) Preparation of an inorganic complex, including ealeulation of limiting reagent, theoretical yield. and % yield. 3) % KC108 in a KCI-KCIOJ mixture and the molar volume of 1)
02.
4) Calorimetry. Standardization of the calorimeter and heats of
reaction. 5) Molecular weight of a "on-electrolyte hy freezing point depression. 61 Inorganic Qualitative Analysis. Cations Groups, I. 11. 111. IV, and V. Students enter their data and calculated results into the terminal upon request of the program. Results are computed with the student data and compared to the student calculated results. The computed result is then compared with the true value. The program computes and prints a grade based on the correctness of the student's calculations and the quality of the experimental results. The grade is also filed for an Instructor's Grade Report. Advantages realized with the programs are as follows 1)
Virtually no instructor time is devoted to grading.
21 Grading is consistent over the 250 students in 10 sections supervised hy 5 or 6 instructors. 3) All student calculations may he checked and the errors indicated to the student. 4) The student's experimental results can be checked even if
the results are miscalculated.
