John C. Cochran, David K. Lewis, William R. Stagg,' and Walter A. Wolf Col~ateUniversity
II
The Integrated Undergraduate Laboratory Program at Colgate
T h e traditional laboratory program, consisting of a course-connected series of experiments bearing little if any connection one with another has seemed less and less to fulfill the needs of chemistry departments and their students. I n this paper a e wish to describe the situation of the Chemistry Department at Colgate University, a liberal arts college, and how a new approach to the upper-class laboratory program relieved many of the previous programs' failures while introducing only a few new problems. The upper-class students should be offered a iaboratory experience that can be tailored to individual need, be interesting, be rigorous and prepare them for their own diverse futures. As we were involved in redesigning the program, we became aware that other goals could also be incorporated, such as (1) the integration of various disciplines (organic, inorganic, ctc.) in individual experiments so as to break down the arbitrary classical divisions between these disciplines, (2) the use of all available talents, including those from other departments, (3) encouragement of students to join in the teaching experience, something particularly difficult to do when everyone is involved in the same experience simultaneously, and (4) the fostering of a sense of comraderie and a research flavor in the program through a weekly seminar delivered by students and faculty. I n summary, we wanted maximum flexibility while requiring a high level of performance and insight. These ideas were implemented as follows. I n his junior and senior years, the student takes various courses (see the table) and, in addition, participates in the upper-class laboratory-seminar program. The program itself consists of a series of experiments (stations) drawn from the various fields of chemistry. Physical chemistry is emphasized since the students have experience in analytical and organic chemistry. Each student must complete a minimum numbcr of experiments, some of which are required. I n addition, each student must attend the weekly research seminars and must participate actively during his senior year. Several key points of the actual operating program warrant discussion. First, the experiments are organized in two ways (see Appendix), by level and by type. Levels A, B, and C refer to degrees of sophistication, with C being the highest. The types of experiments include research skills (numbers 1 through lo), structure (11 through 20), dynamics (21 through 30), and synThe rtuthors wish t o acknowledge the support of the National Science Foundation, No. GY-7845, for assistance in the purchase of some of the instruments used in this program. Present address: Randolph-Macon Woman's College, Lynchburg, Virginia. 24504
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/ Journal of Chemical Education
Junior and Senior Year Courses Semester 1-11 111-IV V-VI VII
Course Quantitative and Inorganic Chemistry Organic Chemistry Physical Chemistry Quantum Mechanics Advanced Organic Chemistry
Enrollment 130-140 80-100 10-20 4 10
thesis (31 through 40). This popular, arbitrary division required some stretching of definitions, but did impose a bit of order on the chaos of more than forty stations. Second, the students are not completely free to choose. All must take certain basic experiments that provide t,he background for successful lab work (A level). These include electronics (A-I), glasshlo~~ing (A-2), library skills (A-3), and computer programming (A-41, topics that often are omitted or assumed, as vell as some more braditional analysis techniques (A-11, A-12, A-21, A-22). I n addition a solution properties measurement (R-12 or B-13), one of the kinetics experiments (B-23 through B-28) and a synthesis (C-31 or C-32) are mandatory. Thus of the approximately 48 weeks in the program, 17 are required and another 6'or so are restricted to a limited choice. Beyond this, the students have great freedom of selection. They can choose any of the remaining experiments, either as is or in an expanded form (vide infra). Scheduling is also freer, so that the order of experiments can be adjusted (within limits of equipment availability) to the most rational sequence. Third, research problems are an integral part of the program. An arbitrarily numbered experiment, C40, represents participation with a faculty member in his on-going research projects. Usually, this would be chosen in the second semester of the senior year. Alternatively, a student interested in any particular station is free to continue working in that area, going as far beyond the original limits of the experiment as is feasible. A fourth key point is that the program is open to the other science students. Individuals from outside the department who are interested in certain areas are free to perform experiments related to those areas. The additional student-student and student-faculty relationships that develop in this u-ay would go far to break down artificial harriers. Hopefully, our students would learn much from contact with these students. Once me had the outline, we then considered staffing. The four faculty members who taught the upper-class courses were to he the principal participants, each in his area of specialization (physical, inorganic, organic,
and biological chemistry). The other members of the department were to participate to a lesser extent. I t was felt that the time involved should be comparable to the traditional course-related laboratory program which it supplanted, though it would be organized quite differently. I n practice the program generated enthusiasm among the students and staff because of the individuality of each program. However it immediately presented a mammoth scheduling problem. I n most cases there was only one set of apparatus available for an experiment; and in some cases two or more experiments required the same pieces of instrumentation. We were faced with twenty-four students each presenting us with his own unique year-long program of experiments which had to be dovetailed with the others without excluding anyone and without trying to use the same piece of apparatus for two different experiments simultaneously. Fortunately we were not restricted to scheduling experiments on any particular day of the week. Rather, expcriments were scheduled by the week and the student(s) scheduled for a piece of apparatus had first priority for that time. Other students, out of phase for some reason, could use the apparatus during that period but on a second priority basis. The organization of the schedule presented a few hectic hours for the faculty member who arranged it but it actually worked out reasonably well. Very few of the experiments requested for first semester had to be switched with those requested for the second semester, and none were deferred to the following year. I n some of the experiments, e.g., computer programming, as many students as possible were scheduled simultaneously to ease the burden on the instructor. In other experiments, e.g., X-ray powder diffraction, students were scheduled for overlapping periods and were encouraged to instruct each other with guidance from the faculty. This new laboratory program may be evaluated on the basis of several points. Its goal is clearly one of developing individual experience and competence rather than verification of principles. It prepares the student by helping him develop the basic competencies of research before he goes on to more advanced work. It provides considerable flexibility to accommodate the diverse goals and abilities of the students. It circumvents the differing expectations of each course by dissociating the laboratory from the course. It provides an opportunity to employ laboratory skills at successively higher levels of sophistication, thus reinforcing the development and understanding of those skills. One persuasive feature of the program is its effect upon the esprit of both faculty and students involved in it. Student interest and enthusiasm is higher because each student's program is tailored by him specifically. The research nature of the third-level experiments imparts a flavor of realism to the program. Contact between faculty and students is usually one-to-one, a learning situation with obvious merit. There is more interaction between all students in the program, as there is both vertical (junior-senior) as well as horizont,al (junior-junior and senior-senior) contact. Students have a maximum opportunity to learn from each other. There is opportunity for involvement of students and faculty outside our own department, a feature which increases the breadth of experience for all parties and
helps to break down the disciplinary barriers. Unfortunately this participation has been limited up to now. Another feature which is increasingly important is that it provides for the maximum utilization of apparatus without duplication. For example, the use of one gas chromatograph is spread over the entire year, and thus money can be spent to purchase one high quality instrument instead of a number of less expensive units. There are two problems which have not been satisfactorily resolved in the program. The first is that some students tend to lag behind in completing the experiments, and are delinquent in submitting their reports. This is partly due to the fact that instructors are supervising so many experiments at once that they don't always keep track of whose report is due at the moment. It is also due to the freedom allowed each student in choosing when he will actually perform each experiment during the scheduled one-to-three-n7eek span. A simple form-memorandum to the student has helped. The second problem is what to do with a student who simply does not complete the work. Since t,he juniors are all taking physical chemistry we have resolved the above difficulty by including the laboratory grade in their grade in the course. For the seniors this is much more difficult to do since there is no common course of study. Therefore, we have indicated that it is a requirement for graduation with a degree in chemistry t,hat the laboratory program be completed satisfactorily. Finally there is the matter of facuky time in t,he program. It is not a time-saver. Demand on faculty time is not reduced as compared with the former courseassociated programs. Some faculty find t,hat their time is more fragmented and there is less time available in large blocks for class preparation and research. Others find that their time is more uniformly utilized than previously. This seems to depend upon the type of laboratory the inst,ructor previously operated and which experiments he presently supervises. I n summary, we have d e v d o p ~ dan excihg, diversified program. student,^ may gain experience in a variety of areas of chemistry while developing t,heir olrn unique integrated programs oriented to~vardspecific goals. The problems which have arisen have not proved insurmountable. Finally, the flexibility of the program admits ready development of nmv experiments and deletion of those which are unpopular or pedagogically less sound without altering the goals of the program or limiting its scope. Appendix
A short description of t,he experiments presently offered appears below. At the beginning of each year a student selects a set of experiments totaling twelve credits per semester. A unit of credit corresponds roughly to t,wo afternoons of vork in the laboratory. During the junior year a student ~ o u l dnormally be expected to complete all of the A level experiments plus a few B level. During the senior year he ~rouldsrlect B and C level experiments with not less than sixteen credits at the C level. This, of course, includes the C-50 research experience which for a semester counts as twelve credits. It should be noted that many students start their research during t,he January Special Studies Period. Volume 49, Number 9 , September 1972
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The references cited are given only to indicate generally the types of procedures involved in our experiments. In many cases the experiments have been modified, expanded, or entirely revised to adapt them to our program. There is much duplication of experiments in the available texts and literature, and it is not the intent of the authors to endorse these sources as superior to others where the same experiments may appear. A Level A-1 Instrument Design. (3 credits) The principles of design and application of analytical instruments are studied using modular building block apparatus ( 1 ) . A-2 Glers Technology. (2 credits) Students are taught s. variety of glass blowing skills. They must demonstrate proficiency a t making T-se&, straight seals, bends and ring seals and must construct a t least one piece of useful laboratory glassware. A-3 Chemical Literature. (2 credits) After a lecture on chemical literature and literature searching, students are given a set of problems of increasing difficulty which require the use of the chemical literature. A-L Comnuter Proorammino. (2 credits) A short course in gram. Development of programs to analyze data. from other experiments is encouraged. A-11 X-Ray Powder Diffraction. (2 credits) The diffraction pattern of an unknown cubic crystal is determined by use of the Debye-Scherrer camera, and the powder diffractometer; assignments are made to thelines and the cell parameter determined (2). A-1% Spcct~oscopy. (2 credits) (a) The uv-visible emission spectrum of an alkali metal is recorded on a spectrophotometer assembled from modules (Experiment A-l), and the recorded spectrum is interpreted (5). (b) The infrared absorption spectrum of SO* is recorded, and the vibrational frequencies, structure, and the heat capacity are determined (4). A-21 Gas Chmmatography. (2 credits) This experiment involves an introduction t o the techniques of gas chromatography. The student is eiven an unknown mixture of comnounds and must separate the mixture, collect enough sample for an ir spectrum of each component and determine by integration the quantitative composition of the mixture. A-$32 Radiochemist~y. (2 credits) This is an introduction t o the deteotion of radioactivity using solid and liquid scintillation techniques.
B Level
studied spectrophotometrically and the rate constants and aetivation energy determined (10). 8 2 4 Kinetics by Polarimetry. (1 credit) The rate of the pseudo-first order, acid catalyzed"inversion" of sucrose is studied 2. a f~tnctiou of pll and trmpernttm 11 1. H-25 Kinr1lr.p-Sprrlro~ropy. ( I emlit) The reaction I,era.een tributvlvi~wlrinsnd h v d n w n Aloride in methnuol solt~timis filllowed~spec~ophotome~rica~ly in the uv. The rate constant is abtained graphically or by computer. B-26 Kinetics by Initial Rate Method. (2 credits) The "iodine clock" reaotion is studied aver a. range of reagent concentrations and temperatures, and the partial reaction orders and Arrhenius parameters are determined. The student is asked t o determine, with the aid of his data, which of the many mechanisms proposed for this reaction is most likely under the conditions of his experiments (22): B-27 Enzyme Kinetics. (2 credits) Simple MichaelipMenton kinetics are illustrated by use of alkaline phosphatase. B-$8 Kineties by Conductance. (2 credits) The rate of reaction of ethyl acetate with hydroxide ion is measured by following changes in the electrical conductance of solutions. The reaotion order, activation energy and probable reaction mechanism are determined (15). B-29 Ozalic Acid Solubility. (2 credits) The solubility of oxalie acid in water is determined as a function of temperature. From these data. much of the oxalic acidMzO nhase d i a a a m can be plotted, and the differential heat of s&tion of oxdicacid can be calculated (14). B-31 Gel Filtration. (2 credits) This technique is used t o separate small molecules (guanosine, GTP) as well as large ones (proteins). B-32 Enzyme Control and Purification. (2 credits) A simple ~uriisolation of E. Coli. Alkaline ~hosuhataseillustrates enzyme . . ficatian and how growth conditiods can influence enzyme production. The enayme solution is used in Exp. B-27. C Level C-11 Single C~ystalX-ray Diff~aclion. (3 credits or more) The structure of sodium chloride is determined using the Weissenberg technique (16). C-18 Dielectric Behavior i n Nmqueous Solvents. (2 credits or more) The dielectric behavior of a nonaqueous solvent and the variation of solvent dielectric constant with various solutes is studied. C-13 Eleet~olytie Conductivity i n Nonaqueous Solvents. (2 credits or mare) The conductances of a variety of electrolytes in some representative nonaqueous solvents are studied and fitted t o theoretical equations. C-21 Solution Calorimetry. (2 credits or more) The enthalpy of of a Lewis aeid-base nair is measured. ~- r~aat,ion C-28 Activities qf ~leetrolytes. '(2 credits) Activity coefficients of sodium chloride solutions are determined using emf cells with transference (16). C-$3 Complez Equilibria. (3 credits or more) The stability constants far formation of a series of coordination complexes in aqueous solution are measured potentiometrically (17). C-$4 Vapor Pvessure by the Knudsen Sublimation Method. (2 credits) The vapor pressure of a slightly volatile organic solid is determined by measuring the rate of sample loss from a Knudsen ~~~~~~
B-11 Atomic Absorption. (2 credits) This experiment involves the dissolution of an ore sample and quantitative analysis of a t least two elements in the ore by atomic absorption spew troscopy. B-12 Dipole Moments of Molecules. (2 credits) The dipole moment of a uolar molecule is measured bv determinine the di-
and acetic acid are measured.and the ionization constant of acetic acid calculated (6). B-14 Molecular Weight by Guseous Effusion. (2 credits) The molecular weights of several unknown gases me determined hv oomnarine the& rates of effusion throueh-s. inh hole into a vacuum wit.h' thrtr of a known eas (70). Results are checked aeainst A
cell is constructed and its emf measured as a function of temperature. AG, AS, and AH for the cell reaction are cdculated. Effects of varying reaxent concentrations are evaluated (9). B-22 Polarography. (2 credits) This experiment develops familiarity with the polarographic technique for qualitative and quantitative determination of trace metal unknowns and for
632 / Journal o f Chemical Education
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C-25 K i n e t i c s 4 a s Chrwnatagraphy. (3 credits) The acid catalyzed exchange reaction of aeetal with methanol takes place by a stepwise mechanism. The complex system can be followed by analysis of aliquots using gas chromatography and from these data, the rate constants for the two steps can be determined (19). C-$6 Gas Phase Kinetics. (2 or 3 oredits) The rate of decomposition of t-hutyl chloride (or bromide, alcobol, etc.) a t elevated temperatures is studied by following the change in gas pressure. Reaction order, activation energy, and effects of free radical contributors or scavengers are determined (20). C-$7 Bomb Calorimetry. (2 credits) The heat of combustion of an organic compound is determined in a. bomb calorimeter and compared with the value calculated from bond energy data (dl ). C-51 Inorganic Synthesis. (2 or 3 credits) One or two compounds w e synthesized which demonstrate a variety of synthetio techniques (22). C-3%Organic Synthesis. (2 or 3 credits) This experiment involves an advanced synthesis of an organic compound. The compound will he chosen from a list representing a wide variety of synthetic techniques (28).
C-55 PPhochemical Cycbaddition. ( 2 credits) The photochemical reaction between cyelooctene and chlarmil is run and the product quantum yield is determined using a chemical sctinometer (Ma,b). C-54 Lipid Metabolism. (3 credits) The synthesis of lipids from acetate is observed in yeast using radio-chemical techniques. C-56 Eledrophoresis. (1 credit) Simple protein separation and immunophoresis are performed. C-56 R a d w c h m t s t ~ y11. ( 2 or more credits) This involves further investigations of the methods of detecting radioactivity. It is designed individually. C-57 Bzosynthesis. (3 credits) This involves isolating various rsdiochemicdly labeled antibiotics from molds. CdO Research. (12 credits) Research in areas related to the specific interests of the stafis of the chemistry and other science departments. Literature Cited (11 W~LLARD, H. H., M ~ n s l w L. . L., A N D DEAN, J. A,, "In~t~uments.1 Methods of Anslusie." D. Van Nostrand. Princeton. N. J.. 1965. Chapters 1. 2. (21 Ref. (11 Chapter 8. (3) S ~ ~ m o nF.o E., , AND WORTMAN. J. H.. J. CREM.E D U C . . ~630 ~ , (1962). . G., J. CHEM.EOUC..47, 391 (19701. (41 B n ~ a a sA. (5) DANIELB. F.. ET AL.. "Experimentd Physicale Chmistry." (7th ed.). MoGraw-Hill, New York. 1970, p. 216.
(61 Ref. ( b ) p. 175. (7) (4 SHOEMAKER, D. P., A N D GARLAND, C. W.. "Experiments in Phydosl Chemistry." 2nd ed., MoGraw-Hill, New York. 1967. D. 102. (bl Ref. (61. D. 4. n nP.. . m n GARLAND. C. W.. Ref. (. 7 4. .o. 309. (8) S ~ o ~ ~ n a D. (9) VIRCSNT, C. A,, J . CHEM.EDVC..47, 365 (1970). (101 ADAM&D. M., AND RAYNOR, J. B.. "Advanced Practical Inorganic o . 140. Chemistry." John milev & Sons. New York. 1965.. . (111 D n l i r E m F.. ET AL.. Rei. (61 p. 149. . W.. Ref. ( 7 4 p. 214 (121 S x o s m * a ~ n ,D. P.. A N D G h n ~ n x o C. (13) Dnmms. F.. ET AL., Ref. (61, p. 144. (14) . . Ref. (6) . . .o. 132. (15) Smns. D. E.. "Introduction t o Crystallography.'' W. A. Benjamin, Nexv York. 1969. (161 BnowK. A. S.. A ~ MACINNES. D D. A,, J . Amer. Chem. Soc.. 57, 1356 ,lo?
