The FlPSE Lectures
Reformatting the Laboratory J. J. Lagowski University of Texas, Austin, TX 78712 Ask any teaching chemist about the importance of a laboratory component in the course helshe teaches and you'll most likely get a response suggesting that laboratory work is critical to the understanding of chemistry. Perhaps there will also be an allusion to the point of view that chemistry is still an experimental science, a suggestion that few would contest. However, there is little direct evidence that supports the point of view that laboratory work is an important component of chemistry instruction-that students who "do laboratory" are hetter off than those who do not. Hlstorlcal How did this presumed importance of lahoratory work come about? I t isn't clear that single historical origin exists for the precedent of laboratory-based chemistry teaching. Before about 1800. chemistrv was harelv recoenized as a separate discip1ine;rather i t was seen as a6 adjuict of medicine. Some notable descri~tionsof laboratorv environments have survived time: ~omanosov'slaborator; a t St. Petersberg (1748). and Stromeyer's a t Gottingen (1810). However, i t is Liebig's laboratory at Giessen (1824) that stands out as the oremier model for most of our current laboratorv practices. Liehig's description of the state of lahoratory work is instructive: "What oeople called llahoratoriesl were rather kitchens filled withall sorbof funnels and utensils for carrying out metallurgical or pharmaceutical processes." After about 1825 the diffusion of chemical knowledge became systematized more or less along the lines we know now. Still..the literature is not a t all clear what was exoected to be accomplished in these "laboratory-oriented" environments. P e r h a ~ the s chemistrv to be learned was so comnlex and so little &derstood t h a t i t was simplest to arrangean apprenticeshio environment in which the student could "learn (something undefined) by observing and doing." The famous boron chemist and master experimentalist H. I. Schlesinger in a symposium on laboratory instruction alluded ( I ) to an ill-formulated apprenticeship kind of environment when he spoke of "an intuitive belief that there should be in laboratory work something which under present conditions (standards) they do not get." There is a curious, but comfortable, vagueness in this Schlesinger quote, which most teaching chemists who believe in the need for laboratory instruction will appreciate. A clue to the nature of the experience expected from laboratory work is also provided by Schlesinger when he stated (I) "Any scheme of [chemical] education i~seriouslydefective if i t does not include planned training in the art of translating observation and thought into action!' This statement, in effect, defines the objectives (from Schlesinger's point of view) of lahoratory experience, viz., to acquire the art of translating the observation and thought into action. Recall that "art is skill acquired by experience, study, or observation." The other point worth notine in the Schlesineer nosition is that laboratorv instruction must be planned,&ggesting that we should n i t leave to chance the acauisition of the art. $chlesineer believed (1) . . that laboratory instruction had the following explicit goals.
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Journal of Chemical Education
(1) To illustrate and clarifyprinciples discussed in the classroom,
by actual contact with materials. To give the student a feeling of the reality of science by an encounter with phenomena which otherwise might he to him no more than words. 13) To make the fact of science easy enough to learn and impressive enough to remember. (41 Togive the student some insight into basic scientificlaborstory methods, to let him use hands, and to train him in their use. (2)
A similar set of ideas has come to us from a student's perspective. Ira Remsen describes (2) an early encounter with chemistry in the following way: While read~nga textbook of chem~atry,I came upon the starement,"nitriear~damsuponcopper." I aaRgettingtired ofreading s Copsuch absurd stuff and I determmed u, see what t h ~ meant. per was more or less familiar to me, for copper cents were then in use. I had seen a bottle marked "nitric acid" on a table in the doctor's office where I was "doine time!" I did not know its of ~eeuliarities.hut I was eettinn..on an> likelvta learn. The soirit adventure was upon me. Having nitricacid and copper, I had only to learn what the words'act upon" meant. Then the statement, "nitric acid acts upon copper." would be something mure than mere words. In the interest of knowledge I was even willing to sacrifice one of them on the table; opened the bottled marked "nitric acid;" poured some of the liquid on the copper; and prepared to make an ohservation. But what was this wonderful thing which I beheld? The cent was already changed, and it was no small change either. A greenish blue liquid foamed and fumed over the cent and over the table. The air in the neighborhood of the performanoe became colored dark red. A great colored cloud arose. This was disagreeable and suffocating.How should I stop this? I tried to get rid of the objectionable mess by picking it up and throwing it out of the window, which I meanwhile opened. I learned another fact-nitric acid not only acts upon copper hut it acts upon fingers. The pain led to another unpremeditated experiment. I drew my fingers across my trousers and another fact was discovered. Nitric acid acts upon trouser. I tell of it even now with interest. It was a revelation to me. It resulted in a desire on my part to learn more about that remarkable kind of action. Plainly the only way to learn about it was to see its results, to experiment, to work in a Laboratory. ~~
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This Remsen quote contains the essence of what most instructors believe should happen during a laboratory experience: buildine a curiositv. ".twine t o understand the meaning of words (lilke "act upon"), obLining specific knowledge. The exoerienced chemist Remsen lookine back uoon his early encounters with chemistry comes &sentiall; to the same conclusion as Schlesinger-"The only way t o learn about it was to see its results, to experiment, to work in a laboratory.'' In more recent times Pickering (3)has argued, "If lab is to illustrate something let it he the scientific method." In this view the laborat~ryex~erience is to he avehicle t o learn how t o solve prohlems. This kind of lahoratory experience is desiened t o Droduce data from which loeical choices can be made. Most of the modern expressions of laboratory instructions have difficulties w ~ t hthat ooint of view. Good (that is. acceptable) data may be difkcult t o recognize,' logical
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choices are not necessarily "right" from the standpoint of a priori knowledge, and the evaluation of student work is not . necessarily easy. lndlvldual Laboratory Work vs. Dernonstratlons Given that there is something to be gained by the student bv "observine chemistrv". does it necessarilv follow that iidividual lagoratory workis the best vehicle tb achieve this eoal? Some would armre ( 4 ) that demonstrations performed Ly experienced indiiiduis provide the same r~sults.Not sur~risinelv,attempts have been made to provide evidence of {he su&iority o i one method or the other (5). Lhfortunately, the data available in literature remains silent on this question for one basic reason-the lack of a measuring instrument designed to determine the "educational product [that is] unobtainable without the laboratory method." In effect, there is a confusion about what to test and how to test for it. The availahle data from oaoer and oencil testsshow no particular advantage of one m%od overanother. With such a conclusion it is not sumrisine" that demonstrations will be chosen in many teaching environments to replace lahoratory instruction.Al1 things being equal (if they really are) demonstrations are clearly more cost effective than providing for individual laboratory experiences (46). Providing for demonstrations does not require the enormous commitment of laboratory space, facultylstaff time, equipment, and consumable~that individual lahoratory instruction implies, even for the most superficial content. At best, and from a pedagogical point of view, we can consider the debate between those who support demonstrations and those who prefer individual labor&ory instruction a draw. A survey (6)of instructorj of the perceived outcomes of eood laboratorv instruction indicates a belief that it improves manipulative skills, self-reliance, resourcefulness, and ingenuity; provides training in making critical observa: tions; and reinforces an understanding of the scientific method. I t must be noted that these Derceived carrv-overs fromlaboratory instruction are beliefs-and not proven in any sense of that word. If it is accepted that teaching chemistry through the vehicle of laboratory instruction improves student skills in manipulation, observations, and organization, as well as higher level cognitive skills, how can modern educational technologies be used to improve the process of this kind of instruction? The technologies of interest to us here are those based on interactive c6mputing. What Do Teachers DO? Before discussing how technology can be used to improve chemistry instruction, it is, perhaps, useful to outline briefly what teachers do. The basic task of teachers-to help students learn-is fraught with "busy work". Teachers have to organize courses, which generally involves preparing and grading: homework quizzes examinations laboratory work In addition, teachers have the responsibilitv t o produce feedback tostudents in the areas cited above. ~ n finally d teachers need to keep records to assist them with the administrative tasks associated with these elements of instruction, i.e., those directed toward the overall evaluation of a student's performance. With regard to laboratory work, we conclude that teachers help students enhance their skills in manipulation, observation, and organization, as well as higher level cognitive processes. How Can Computers Help? Computing has been found useful in virtually all areas of the educational process in which teachers and students have
a leeitimate interest. i.e.. homework. auizzine. and laboratory instruction. wheneve; a teacher wants to &troduce one of these instructional elements into the educational Drocessfor whatever pedagogical or philosophical reason-computing becomes a powerful tool to do so. Computer-based elements of instruction are highly individualized, which means that no two student experiences-whether, they be for a single student or two different students-need be the same; they are available on demand; and records of student work arekasilv maintained. Let's rook at how the elements of quizzing and homework can be used to imorove the student ex~eriencein the laboratory. Since laboratory instruction is often separated in time from the didactic art of a chemistrv course. it is often difficult for studenis to relate the details of subjects developed in depth in formal lecture to a particular laboratoryoriented experience. The assignment of suitable homework problems can be used to bridge this gap. We all recognize the difficulties with homework prohlems, viz., most students aenerally do not actually solve the problems themselves or insufficient quality resources are available to grade the problem sets. Under such conditions, the practice of creating, disseminating, and grading problem-sets degenerates into an exercise that leads to relatively little learning. Then, a sound and defensible element of instruction does not produce maximum results because of logistical problems. Interactive com~utinetechniaues can be used t o alleviate manv of these problems. I t is possible to produce, with computers, individualized homework sets of problems. That is, each problem in agivenset is different in some respect from every other problem in other sets for a given assignment; the differences can be in wording and/o;numericvalues that may appear in the problem. Thus, a class of 500 students would be issued 500 different problem sets for a given assignment, producing a highly individualized learning environment. In such environments it is auicklv obvious to the individual student what is expected bf hikher-individual effort apDlied to individualized assienments. Althoueh there mav be relatively large fraction of a class that $11 be willing to share the details of their work with their peers, there are probably vanishingly few students who will do their own work as well as that of a friend. A system that can produce individual homework sets on demand obviously has the capacity of grading them on demand and keeping records of the results. Quizzing can exhibit the same character in a lahoratory settine as homework oroblems. Thus. we can imaeine the peda&icalusefulness'of insisting that students come to the laboratorv with a minimum of knowledee about the work they are lxpected to do. Pre-lab quizzes, covering subjeds such as safetv. e s materials, the opera.. common ~. r o.~ e r t i of tion of equipment, and the organization of data can be emDloved to helo focus student attention on certain details of ihe-proposed-laboratory work that are perceived by the instructor to he imoortant for efficient work in the lahoratory. Pre-lab quizzes can be given on a pass-fail basis and tuned a t whatever level a teacher deems as sufficient. As in the case of homework sets, pre-lab quizzes can be highly individualized, produced and graded on demand, and records kept.
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Slrnulatlon of Laboratory Experiences Althoueh interactive comouting cannot be used easily to improve manipulative laborkory ;kills directly, a number of strateeies involving simulation can be employed to augment wet-l&oratory experiences. Computer simulations can be used to anticipate a laboratory experience, making it more meaningful for the student. For example, a simulation of the classical n-solution experiment, which can be done in less than an hour, can be employed to illustrate the use of p r o p erties and the strategy of thinking involved in a conventional qualitative analysis scheme. A student can derive considerVolume 66 Number 1 January 1989
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able insight into the nature of aualitative'analvsis bv- Der. forming ibe he-solution experiment. In contrast with simulations that provide an advantaw in anticipating a wet-laboratory expeiience, simulations'that extend a wet laboratory can also provide a richer student experience. For example, a simple wet-laboratory clock reaction can be performed in a conventional laboratory period to illustrate some of the elements of kinetics. However, it is generally difficult to explore the parameters that could affect such Drocesses.. ex.. " . chanees in concentration andlor temperature, in more than a cursory way in a wet laboratory. A well-designed simulation, working in concert with the wetlaboratory experiment can be used t o provide a richer laboratorv experience than is available through the wet laboratory alone: Although there are numerous examples of simulations augmenting wet-laboratory experiments to produce learning environments that are more meaningful than a wet laboratory alone can provide, the two examples given here will suffice to illustrate the ~ r i n c i ~ l e . Successful simulations th'at augkent wet-laboratory work exhibit a number of common characteristics; they generally require students to make detailed decisions covering the choice of e a u i ~ m e ntto be used. how it is to be manipulated. and what chimicals or solutioki are to be used. i n othe; words, successful simulations involve the student in as manv decisions about strategy, choices of materials, and organiza"tion as do wet experiments. Successful simulations expand or compress time for the students and the instructor, they save money because chemicals are not consumed, and they are a vehicle for "performing" potentially dangerous experiments. Course Admlnlstratlon To this point we have discussed computer-based methods that could be used to augment parts of the laboratory instructional process. Computing can be used to advantage to integrate these parts to produce a whole that appears to be more useful than each of the individual Darts. Althoueh there are probably a number of different ways the elements discussed here could be ~ u together t to Droduce a viable course, we discuss now the specific structure favored a t The University of Texas, which illustrates some of the points where philosophical choices can, and must, be made. The discussion is focused on a general chemistry laboratow course for science students, which in our environment is a two-credit-hour course separated from the conventional lecture components. This structure was dictated by constraints involving the numbers and kinds of students we had to service in the mace available. The course consists of one hour of lecture, one computer laboratorv, and one four-hour wet laboratorv each week. We have arrahged the schedule so that eacbstudent receives his/ her instruction in the sequence lecture, c o m ~ u t e laborator ry, and wet laboratory. w i t h this general str&ture as a basis we have created the cycle of work illustrated in the fimre, . which is computer mediated. The student enters the cycle by doing the prescribed prelab work. When helshe is ready t o perform the experiment, the student must pass apre-lab quiz (described earlier). The quizzes, which do not enter into the student's -grade.. are given on demand and on a pass-fail basis; our pre-lab quizzes can be imagined as the "guardians" of the laboratory gate. When (not "if") the student passes a pre-lab quiz, he/ she is permitted t o perform the experiment whether it be a wet or a simulated lahoratory experiment. If the student fails the pre-lab quiz, helshe is directed to do more studvine and then come back to retake the quiz. Our philosoph$ on this point is that we would prefer to have the unprepared student "in the hall" studying to get into the laboratory rather than in the laboratory creating confusion among his/ her colleagues trying to figure out what to do. The process works remarkably well.
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Journal of Chemical Education
Returning to the figure, after the student "does" the experiment and collects the pertinent data, helshe organizes it and reports the results. Some of the reports are com~uter based (e.g., if the objective of the experiment is a numder) or they are short written r e ~ o r t that s are eraded bv the assistants. After the report ismade, the stuient staris on a new experiment. Thus, the cycle of work is driven by student effort, with the key being the pre-lab quiz. The cycle is automatic, in the sense that the instructional system will always produce another pre-lab quiz and a homework set. The instructional system produces the elements of instruction-pre-lab and homework-grades these and keeps the relevant records, which are available to the individual students and the instructional staff, on demand. Conclusion
Given that laboratory instruction has something to offer in the education of students, the meatest sinele ~ r o b l e m with the current process of laborkory instm&n is the logistic impediment to the student gaining access to meaningful experiments. The logistical problems stem from the number of students involved (20 students can be a large number of certain kinds of courses) and the time constrain& related to the nature or complexity of the experiments and the resources allotted for laboratory instruction. These factors generally conspire to produce an instructional mode, currentlv in vogue. that can onlv he described as a "cookbook approach." ~ " e r ~ t h ai &dent n~ does in the laboratory is over-specified: we cannot afford t o allow students to make mistakes because of safety andlor logistic reasons regarding the availability of certain resources, e.e., sDace, time, chemicals, and equipment. An environmeniwheremistakes are not allowed becomes sterile and uninteresting in the extreme, as illustrated by many of the general chemistry courses that are offered. The use of computer-based methods can produce a very rich laboratory experience. Certain administrative, but pedagogically important, aspects of laboratory instruction can be improved through the use of such techniques, and computing can be used to Droduce simulations that aumnent the iaboritory experience. I t is apparent that we now have the capacity to return the ambience of laboratorv instruction to thk point where it can again "provide trainkg in observation, in thought, and in considered action." Literature Clted 1. Schleaingar.H.I. J . Chom.Educ. 1935.12.524. 2. Getmar. F. H.The Life o f i m Remen: Journal of Chemical Education:Emton. PA. 1940. 3. Pickerins M. J. C k m . Edue. 1986.62.814. la. Knor, W. W. J. Chem. Edue. 1935.12.166, ard rsfsrsnesa thuein. 4b. Hunt. H.J. Chem. Educ. 1935,12.73. 4c. H0rton.R. E.J. Chem. Educ. 1929.6,1130. 5. Payne, V. F. J. Chem.Edur. L932,9,932,and rsfuenes~therein. 6. A d m , C. S.J. Chem. Edur. 1942.19.266.
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A flow diagram describing the cycle of work in a cornputer-supplemerded laboratory course.
