Plenary lecture: The integrated laboratory in chemistry - American

Plenary Lecture: The Integrated Laboratory in Chemistry. Speaker: J, C. Martin, University of Illinois. During the past few years it has become clear ...
0 downloads 0 Views 5MB Size
II: The lntegrated Laboratory Chairman: David N. Harpp, McGill University

Plenary Lecture: The lntegrated Laboratory in Chemistry Speaker: J. C. Martin, University of Illinois During the past few years it has become clear that many of the disadvantages of the traditional laboratory curriculum, made u p of a series of courses each of which is centered in one of the traditional disciplines of chemistry, can be avoided by recasting these courses in a new format which has come to be known as the integrated laboratory curriculum. This move toward a more logical development of the laboratory experience for undergraduates has grown out of a developing change in the generally held philosophy of research. Although not all research workers are in interdisciplinary fields, many of them are, and the rest have come to realize that the boundaries of the traditional fields of analvtical. inorganic. organic. and ohvsical chemistry can be cdnfiuiig. ire and more chemi'sts have become interested in systems of chemistry (biological chemistry, mechanistic chemistry, environmental chemistry, etc.) which have demanded a widening of interests beyond the traditional boundaries. These ho"ndaries have become blurred as they have so frequently been crossed. The scale of the efforts at integration of undergraduate curricula has varied from school to school, as illustrated by the variety of approaches evident in the abstracts of other papers a t this conference. Most have opted to begin with somethmg less cataclysmic than a complete revamping of the entire undergraduate curriculum, which would erase all disciplinary boundaries. On the other hand, many schools have undertaken a degree of change which represents a real committment to the idea of integrated instruction, most importantly with respect to the integration of the study of chemical instrumentation throughout the laboratory curriculum. At the University of Illinois planning began in 1966 for a three-course integrated core laboratory sequence for our undergraduates. It was first taught in 1968. Professor T. L. Brown, who undertook the job of shepherding these courses throueh their initiation and earlv develooment. has descrihedthem in sufficient detail to make a detailed description here su~erfluous. The vroblems of devisine and introducing such a new curriculum have several aspects: (1) political (the development of a faculty consensus for the change), (2) pedogogical (the development of laboratory experiments and procedures to express the new philosophy), and (3) financial (funding the new equipment needed to translate plans into practice, an endeavor which was greatly aided by National Science Foundation Instructional Equipment Grants). As these problems were solved they were replaced by a set of problems more characteristic of a mature program. While differing from the problems of the start-up period in detail, they maintained the same elements: (1) political (faculty members persuaded of the merit of this new curriculum need further persuasion to undertake personally the teaching of an interdisciplinary course-it is particularly important for an interdisciplinary course to rotate assignments among professors from the various disciplinary backgrounds); (2) pedogogical (experiments must, of course, be up-dated and perfected); and (3) financial (a course designed to introduce the student to a laboratory experience closely reflecting research methodology must frequently acquire new instrumentation to reflect new standard procedures in the research community).

The most persistent problem in the administration of an integrated laboratory sequence stems from the central role of instrumentation in modern lahoratory practice. The student must be given access to appropriate instrumentation a t the point in his investigation when it offers the most direct way to answer a question. This means that a certain amount of expensive instrumentation must he available early in the curriculum if the student is to come to regard chemical instrumentation as a powerful universal adjunct to research, rather than as a separate field of study-in other words, if it is to become an integrated part of his laboratory experience. For example, the first-course in our sequence, "Structure and Synthesis," uses glpc techniques and infrared spectroscopy routinely. The benefits of this clearly outweigh the inconvenience occasioned by the need to stagger the schedules of students in a course so as to evenly space the demand for precious instrument time. As new instrumentation becomes standard in research practice, efforts must he made to replace obsolete methodology in the lahoratory curriculum. This means a continuing effort to obtain funding for appropriate new instrumentation. For example, the second source in our curriculum, "Dynamics and Structure,', is currently being revised to incorporate high-pressure liquid chromatograohv technioues. The isolation. bv hvlc. of cis-azobenzene from a photostationary state cis-trans mixture is followed bv a kinetic studv of its thermal reversion to eauilibrium. Analytical mode hplc with ultraviolet detection'is used to follow the cis-trans isomerization. The third course, "Chemical Fundamentals," is using the capability of the newly acquired Hewlett Packard 9820 desk calculator to introduce an optional "literature" experiment involving the production of stereo pair drawings of crystal structures, chosen by the student from the original literature, to search for evidence for intramolecular or intermolecular interactions in the crystal. The program used for this is similar to one described by Professor D. Y. C ~ r t i n . ~ The same calculator is used for data reduction in several kinetics experiments, providing a flexible plotting capability which is very helpful in encouraging the student to examine in detail how the control of various experimental parameters is reflected in the error analysis. The core lab curriculum has proven to be popular with students and stimulating to the professors who have taught its courses. Our undergraduates move into their undergraduate research program with greater confidence and with a more appropriate repertoire of lahoratory skills than was the case before the introduction of this curriculum. It is clearly to be considered a successful innovation.

..

Acknowledgment

The recent development of the core lab courses owes much to Professors Lion Belford, John Shapley, and Kent Barefield and to the National Science Foundation for grant GY10835. Brown, T. L., J. CHEM. EDUC., 49,633 (1972). Curtin, D. Y., J. CHEM. EDUC., 50,775 (1973).

Volume 52, Number

1. January 1975

/

31

Contributed Papers The Integrated Laboratory, Part I: In Chemistry

Irvin M. Gottlieb a n d William A. Shergalis, Widener College, Chester, Pennsylvania In the academic year 1968-69, the laboratory sequence for the B.S. degree program in chemistry at Widener College (formerly PMC Colleges) was restructured. The freshman and sophomore levels were designed to develop within the student a proficiency in the techniques, methods, and designs of experiments from the subspecialties of chemistry in preparation for the experimental or intergrated laboratory of the junior level and for Independent Study in the senior level. The traditional and specialized laboratories of the junior and senior levels previously associated with courses in physical, analytical, instrumental, and inorganic chemistry were deleted in favor of a selfsustaining laboratory sequence emphasizing the prohlemsolving approach and incorporating these various suhspecialities within each lahoratory project as conceived emphasis is placed on the integration and application of basic chemical principles, irrespective of subdiscipline, and on the enhancement of the faculty and ability of the student to solve problems and to write and present meaningful reports. Each project requires the fusion of techniques and theoretical concepts utilizing general methods too often rigidly and erroneously classified as "belonging to" one specific chemical domain. Elimination of the restrictions of course-related laboratory work in the senior level allows the student to proceed with a modest research program.

The Integrated Laboratory, Part II: In an Interdisciplinary Curriculum in Physical Science

Irvin M. Gottlieb, Fkancisco J. Navarro and Angus Neaves, Widener College, Chester, Pennsylvania Under an NSF-COSIP grant an interdisciplinary curriculum in physical science was developed which integrates broad concepts from chemistry and physics through mathematics. One of its components is an experimentationcommunications "track" consisting of laboratory experimentation with concurrent training in report and technical writing and presentation, in foreign technical language, and in computer applications. The laboratory functions to develop within the student an appreciation and mastery of some simple techniques, methods, and design of experiments. Each experimentation requires the fusion of techniques and theoretical concepts, utilizing general methods which are often erroneously classified as "belonging to" one specific domain. Small "problem-solving" situations are carried out under minimal supervision. The system under investigation is stressed, not the "black box." The purpose of laboratory instruction is to teach students how to design and execute experiments and is not to be considered as another teaching medium for illustrating principles discussed in lecture. The laboratory program should stimulate the imagination of the student with experiments that he can recognize as worthwhile as he concurrently explores the fundamental techniques used in modern scientific research. This purpose can he attained by exposing the student to the following during the first three years: (1) The understanding and use of various laboratory instruments in experiments designed to show the range and limitations of such instruments. (2) Experi32

/

Journal of

Chemical Education

ments designed to show how the physical and chemical properties of the investigated system are revealed from the instrument data. (3) The planning, assembly, and design of instrumentation for the requisite experiments necessary to elucidate some property of an assigned system. (4) Instruction in the execution of arithmetical algorithms by the computer. The senior year is left free for independent study.

A CP-Grade Laboratory (Creeping Professionalism), Part I: The Introductory Sequence

William W. Porterfield and Herbert J. Sipe, Jr., Hampden-Sydney College, Hampden-Sydney, Virginia The laboratory courses in chemistry a t Hampden Sydney College (750 male students) are based entirely upon individualized projects that .are designed to introduce students to the modern realistic practice of chemistry. The introductory laboratories (serving 75 freshmen and 45 sophomores) have projects that are individualized within a category and that stress the acquisition of laboratory techniques, simple experimental design and measurement, and use of the chemical literature. Freshmen are given four projects averaging seven weeks' length; in each of these the student works on his own unique project. He gains experience in techniques because they apply naturally to the goal of his project. Working toward his own goal, the freshman learns in this context the use of gc, ir, nmr, and ms; he learns volumetric and gravimetric techniques in analyzing compounds he has synthesized; he learns the use of chemical literature, including CA and primary journals, in order to establish the synthetic route for the above compounds; and he learns to apply chemical theory in interpreting a sophisticated physical chemical measurement (such as bomb calorimetry, potentiometry, or radical-ion esr). Sophomores have organic-oriented projects, emphasizing semi-micro synthetic and separations techniques, including quantitative gc, followed by appropriate spectroscopic characterizations. The fourth semester is devoted to large-scale, multistep organometallic synthesis designed to yield compounds of interest in faculty research areas; in ensuing years, his laboratory projects will usually he chosen from these areas.

A CP-Grade Laboratory (Creeping Professionalism), Part I I: The Advanced Sequence

Herbert J. S i ~ eJr. . a n d William W. Porterfield.

ampd den-Sydney College, Harnpden-Sydney, Virginia

In the introductory laboratory sequence the student has not only acquired many techniques basic to contemporary chemical investigation, he also has received attitudinal preparation for independent work. In the advanced laboratory (enrolling 20 students) the pattern begun earlier, in which the student encounters projects of gradually increasing sophistication and must accept a greater and greater role in defining the project and designing the procedure, is continued and extended. Projects are of increased and varying length, no longer fit a general category, and are oriented toward individual faculty research

numerous experimental techniques, types of reactions, and structural concepts (modes of bonding, stereochemistry, etc.) which are common to inorganic and organic chemistry are presented and illustrated in order to unify and reinforce the fundamental concepts common to both areas. A significant part of the revised laboratory program is implementation of "bands on" use of instruments, and other apparatus, by students. The first-ouarter lahoratorv emnhasizes techniaues required for synthesis, separation, and characterization of inorganic and oraanic compounds. The second-quarter lab usesua project fo&at where students prepare and characterize organic, inorganic, and organometallic compounds. In the third-quarter lahoratory, an introduction to organic qualitative analysis is presented along with projects which compare nucleophilic and electrophilic substitution processes in inorganic and organic chemical systems.

areas. We view the nurnose of the advanced l a b o r a t o ~not as the provision of specific expertise for the student b k as the development in him of a confident and indewndent state of mind that will permit him to attack futuie problems with the techniques of that future time. The student is expected to take a vaguely stated problem and carry out the cyclic process of literature search, precise problem definition, and experimental design, so that he may propose his own experimental program to the faculty in written form. This research proposal is reviewed in a conference between the student and supervising faculty members; when i t has reached satisfactory form he begins laboratory work and continues weekly conferences in which he reports his progress and plans future work in its light. When his project is complete, he prepares a journal-style report and delivers an oral report to a student-faculty seminar, and perhaps to a regional scientific meeting. By the time the student graduates he has completed an average of four extended projects; he has thus received more extensive research exnerience than is available in a senior honors project. This repetition improves his appreciation of the philosophic basis of scientific research.

A Unified Laboratory Course on Instrumentation and Measurements for Undergraduate Chemistry Majors

Inquiry-Oriented Laboratory Instruction

Richard D. Sacks, University of Michigan, Ann Arbor, Michigan

Fabian T. Fang, California State College, Bakersfield, California The opening of California State College, Bakersfield in 1970 provided a unique opportunity for experimentation in curricular development and innovation in instructional approach. The Department of Chemistry at this new institution has been developing an inquiry-oriented curriculum with initial emphasis on organic and biochemical studies. All chemistry courses comprise minimal lectures, much lahoratorv exnerience. and considerable discussion concerning the experience. Laboratory work occupies a maior oortion of the class time in each course. Such lahorat&ryorientation provides students with opportunities to learn chemistry through working on problems or projects of interest to them and in part of their own selection. Students at all levels are encouraged to design their own illustration of chemical principles and applications of chemical concepts, rather than repeating standard exercises with nredictable results. Laboratorv work is almost completely~open-ended, and experiments are oriented toward solution of nroblems and development of models. Students are expected to feel the excitements and frustrations of practicing chemists. Specific experience of such laboratory instruction from courses in "Basic Principles of Organic Chemistry," "Concepts of Molecular Architecture," and "Concepts of Chemical Reactivity" are discussed.

. .

Synthesis and Techniques Laboratory-A Sophomore Inorganic-Organic Laboratory

J. F. Wolfe, L. T. Taylor, M. Hudlicky, D. G. Kingston and John G. Dillard, Virginia Polytechnic Institute and State University, Blacksburg, Virginia An undergraduate chemistry program is commonly organized within boundaries of general, analytical, organic, physical, and inorganic chemistry. In an attempt to surmount these classical barriers the lahoratory program for chemistry majors at Virginia Tech has recently been revised in order to equip its graduates to recognize and to master the fundamentals of the science as a whole rather than as individual subdisciplines. The former senior inorganic and sophomore organic laboratories have been combined into a single sophomore lahoratory. The pedagogical advantages of the revision at the sophomore level are that

The rapid proliferation of complex instrumentation systems renders present methods of teaching instrumentation concepts and measurement techniques quite inadequate. The usual approach of describing each instrument as a separate and isolated system lacks the generality required to acquaint undergraduate students with the salient features and limitations common to certain classes of instrumentation systems and measurement techniques. A viable lahoratory course should be structured along the same principles as are operative in a modern measurement system. A course of this type has been operating on a pilot basis in the Chemistry Department of the Uoiversity of Michigan. The course is designed for sophomore or junior chemistry majors and is to precede all other advanced chemistry laboratory courses. About 50 students take this course per year. The course material divides into three sections each of which considers one of the basic functional components of an instrumentation system. The first section deals with electrical measurement techniques and signal processing circuits. In the second section, which consists of studentdesigned and tested experiments, these methods and circuits are used to study the salient features of a number of electrical innut transducers for the measurement of temperature, pressure, solvated ion activity, and radiation intensitv. The use of transducers in Feedback lwns for control applications also is considered here. The last section, also of student-designed experiments, combines the signal processing circuits a n d transducers with dispersion elements such as gratings, magnetic fields, and chromatographic columns to synthesize complete instrumentation systems. The philosophy of this new teaching approach was discussed. The structure, contents, and teaching methods used were presented in detail. The effectiveness of this course was discussed in terms of student reaction and participation as well as its relation to other advanced chemistry laboratory courses.

Integrated Laboratory and the Small Honours Program

N. J. Bunce, University of Guelph, Guelph, Ontario, Canada An Integrated Laboratory has operated for three years in third-year chemistry a t the University of Guelph; it follows two years of traditional laboratories, and accomVolume 52. Number 1, January 1975

/

33

panies lecture courses in biological, inorganic, organic, and physical chemistry with projects in these areas. The laboratory serves primarily the Department's Honors and Major students (6-12 annually); other students with less previous chemistry may he enrolled in one or two lecture courses. Students select projects from those available, aided by a faculty member's suggestions of projects most suited to the student's background and current lecture courses. The aim is to introduce students to the maximum range of equipment and techniques available in the Department; consequently, sufficient apparatus exists for only one of each experimental set-up. Thirty-six assigned hours of experimental work are required for each lecture course; projects typically take from five to twenty hours in the lahoratory, which is open twenty hours weekly to accommodate lengthy procedures and permit timetable flexibility. A successful innovation has been to allow students to Dropose and c a m out extensions to oroiects for additiokil -credit, inrrea;ing interest in the kxperiments. Hem r t i in the style of journal articles, fuNv referenced, are ;equired for ail proj&s. Student acceptance of the arrangements has been good and the only major drawback has been the expense of running a lahoratory of this type.

The MIT lntegrated Laboratory Program

Jeanne K. Krieger, Massachusetts Institute of Technology, Cambridge, Massachusetts The three-semester integrated lahoratory program at MIT is designed to give the student experience in the methods and techniques of modern research. Experimental chemistry is regarded as a separate sub-discipline of the curriculum. The sequence is usually started in the third semester by chemistry majors and taken concurrently with courses primarily in organic and physical chemistry; however, the introductory course is offered in both semesters and serves the nonmajor as well. The introductory semester course, with a maximum enrollment of 200, emphasizes methods of preparation, isolation, purification, and characterization of liquids and solids, both organic and inorganic. The intermediate course, with a maximum enrollment of 85, emphasizes equilibria and thermodynamic measurements using more advanced synthetic and analytic techniques. Infrared and ultraviolet spectroscopy, chromatography, potential and polarographic measurements, kinetic determinations, and elementary electronics are introduced. The third semester affords opportunity for experience in advanced synthetic organic and urganometallic techniques, measurements of kinetic phenomena, nuclear magnetic resonance, electron spin resonance, interpretation of mass spectra, and application of computers to the solution of chemical problems. Of the 21 experiments, only 12 of which are performed by any individual student, each is designed, insofar as possible, to incorporate synthetic methods, purification, analysis, and physical measurements, at a level appropriate to the background of the student. "The Preparation and Equilibration of the Isomers of 2,3-Dimethylhutene" is a typical experiment a t the intermediate level which typifies the philosophy and format of the integrated lahoratory sequence.

An lntegrated Junior-Senior Chemistry Laboratory at Elizabethtown College

John P. Ranck, Elizabethtown College, Elizabethtown, Pennsylvania A three-semester integrated laboratory course including synthesis, separations, analysis, determination of physical properties, structures, and reactivities, as well as instrumentation and computers has been taught at Elizahethtown College for five years as the only laboratory course for junior and senior chemistry majors. The stated objective of the course has been "to develop in the student the 34

/ Journal of Chemical Education

ability to think and act like a chemist as much and as early as possible." A small number of many-faceted projects is used in preference to a larger number of shorter, more self-contained experiments. Several schedules have been tried. F,xecution of the synthetic aspects of several "projects" at the same time followed by the separations, considered together, followed by analysis, physical properties, etc., provides a helpful structure that is not to he found if each project is completed in all its aspects before the next is begun. We believe that the former approach is more satisfactory a t the introductory (junior) level, hut that advanced (senior) students should be able to provide their own contexts for different aspects of a project. Difficulties and failures as well as successes are reported. Problems in obtaining Departmental certification by the American Chemical Society Committee on Professional Training hecause of this "nun-standard" lahoratory are also reported.

An Integrated Synthesis Laboratory for the Sophomore Year

Wesley Pearson a n d Albert E. Finholt, St. Olaf College, Northfield, Minnesota A four-semester sequence of intermediate lahoratory in the sophomore and junior years and an advanced laboratory in the senior year independent of lecture courses have been instituted. The intermediate lahoratory contains synthesis, analytical measurement and physical measurements sections and is required of all chemistry majors. Basic to the four-semester intermediate lahoratory sequence is the two-semester long synthesis lahoratory beginning in the sophomore year. Both organic and inorganic syntheses are performed integrating the theory and techniques basic to this type of laboratory work and to the analytical means used for purity and structure determination. S ~ e c i a lattention is given to the selection of experiments which illustrate important synthetic methods-and which allow appropriate use of s ~ e c t r o s c o ~analysis. ic The latter portion'bf ibis two-semester sequence is a project designed to give the students experience in planning and performing a fairly sophisticated synthesis which is selected from a suggested list of syntheses. The R.P.I. Unified Laboratory Program

D. A. Aikens, R. A. Bailey, G. G. Giachino, J. A. Moore, a n d R. P. T. Tomkins, Rensselaer Polytechnic Institute, Troy, New York Rensselaer Polytechnic Institute has adopted a foursemester lahoratory program which combines analytical, inorganic, organic, and physical laboratory work into a unified lab. It has been designed to replace the "conventional" lahoratory courses required of chemistry majors. The primary goals have been to establish good techniques a t an early stage (especially for quantitative work), to emphasize problem solving and selection of techniques, and to develop independence in the lahoratory. Modern instrumental techniques are introduced a t an early stage and used routinely throughout. The themes of the four semesters progress through analytical and separation methods, synthetic methods, and physical property studies although no semester deals exclusively with any one theme. Each semester consists of several experiments normally extending over several laboratory periods and involving a sequence of measurements. With some restrictions necessary to retain the developmental sequence, experiments can be rotated to reduce requirements for specialized equipment. All experiments have been chosen for reasonable costs. The program is now in its fourth semester with the first regular class of 40 students, and in the second semester with the second class of 60. A pilot group has already completed it.