2 electrons" or "add 1 neutron," and the simulated atom would he changed accordingly. If the resulting atom is unstable it will decompose by an appropriate process, such as electron capture, producing a more stable structure. All processes that occur in the simulation are those that are found in a table of nuclides. In simulated time a student has about 10 s to add or remove more subatomic particles; if he does not, decomposition will occur. When a student achieves a stable atomic configuration he is rewarded with some information about the history and discovery of the element formed. A third example is a program under development by Robert Rittenhouse of Walla Walla College for the SERAPHIMI ChemCom Interface Proiect. This oroaram is based on Rutherford's equation forscattering of aparticles by metal foils. A student is sumlied with several experimental tools: an a-particle scattering apparatus; severaf metal targets; a detector and pulse-height analyzer; a digital microscope for viewing things on the atomic level; a data-disk notebook; a data analyzer that can perform mathematical operations such as squaring all X values in a set of X,Y pairs; and a data plotter. With these tools a t his disposal the student can he assigned simple or complex research projects. For example: "Show that the number of a particles scattered a t 30" is proportional to the number of particles that strike that target;" or "Find the relationship between angle of scattering and number of a particles that strike the detector a t that angle." In the first case the student is told what to look for and the relationshio is direct nrooortionalitv. so a simole olot will do. The second case is mnch'tougher and should o h yb e assigned to a good student. By tailoring assignments to students' abilities one can use the same simulation a t several levels. The last examole involves an environmental simulation. where the real experiment would involve potential harm td oeoole and the rest of the biota. I t is being develooed for the % K ~ \ I ' hi H IChemCom Interface ~ n r j e c i h y~ o h nK. Estell. ;a comourrr science student at the Univercitv ot ToIedo.The program casts the student into the role of i n operator of a sewage treatment plant who must decide what percentages of sewage flow to treat by primary, secondary, and tertiary methods. The student must stay within a budget while maintaining water quality. Tax& and fines are levied for polluting, and the incompetent student's stimulation will end with his being fired. Students compete to see who can achieve the greatest budget surplus. The simulations described here all make use of the computer's ability to store, process, and recall data, to calculate quickly and accurately, and to display results in non-numeric or graphic forms. They allow us to invert the normal process of learning about models. Students can vary parameters, ohserve the effects almost immediately, and become familiar with the outcomes of realistically complex models. Students can be placed in the positions of real-life chemists and can learn the insights and modes of thought those chemists use in their work. The challenge to us as teachers is to devise a broad ranee of such interactive. instructional simulations that combine flexibility and convenience of use with general and realistic models. Such oroerams will not reolace TA's, orofessors, or labs, but thky will challenge all b f us to repiace time-honored but less-than-optimal pedagogic approaches to many aspects of chemistry.
Computers in the Freshman Course; Where Do They Perform Best? J. J. Lagowski University of Texas at Austin Austin. TX 78712
Over the Dast 20 vears the exoerience of a few " erouos . in using academic computing in malfnstream chemical education has indicated the modes where computer-based methods can 32
Journal of Chemical Education
be successful; there is ample evidence, both objective and subjective, to support these suggestions. The modular nature of computer programs leads to pedagogical and administrative benefits. A program that has been designed carefully to achieve a specific~oh&ctive,e.g., to simulate a chemical phenomenon, probably can be used to advantage at numerous places in the curriculum; indeed, it may be used several times to help achieve a different overall impression of the subject. Programs may be made available to different students in different sequences, depending upon differing student background characteristics and career goals. The existence of modular programs leads to an educational flexibility that encourages self-paced and oersonalized instruction. Finally, such &mputLr methods are easily adaptable to detailed record-keeoine . - for a varietv" of ourooses. . . including student evaluation or counseling, program improvement, and pacing the course to the student's needs. All too frequently, teachers become overly involved in logistical and administrative functions to the detriment of teaching; that is, they have the burden of assigning, grading, and giving feedback on homework and tests, helping students with their assignments, conducting tutoriallremedial drill group interactions, and organizing individual laboratory work. Successful computer programs have been written that engage students in a tutorial interaction which can he used for drill. review, or remedial purposes; which simulate portions of laboratory experiences; and which produce interactive examinations or quizzt~son demand. I t i i apparent that such programs mimic many the tjiiks in which teuc hers normallv engage. To a large extent the computer can perform these tasks (on an individual basis) as well as, or better than, the instructor, since programs are infinitely patient. Indeed, we can imagine a learning system incorporating such programs as extending the capabilities of the teacher in space and time. In such a system, the teacher retains hislher usual teaching role but trades the roles of bookkeeper, grader, and all-around paper shuffler for the roles of counselor, guide, and mediator. TutoriallDrill Programs In chemistrv. as in all subiects. there are manv oedaeoeicd situations thatrequire a patient tutor to guide the &;lent through a logical sequence of steos in a (relativelv) " . closed subject with respect tb information.content. Usually the point is driven home by the use of numerous examoles that are variations on a thkme. Classically, such situations have been exploited by recitation or discussion periods and the use of homework problems. It is possible to-write highly sophisticated programs for interactive computer systems that capture the detailed strategy that an individual teacher would use in a tutorial session. In essence, that teacher (in the form of the program) is unbounded in space and time since the program can he run a t any time of day and can be transmitted to any geographic point the communications system permits. The alleviation of the logistic constraints imposed by the availability of rooms and/or instructors is ob&us. Laboratory Simulation Programs Laboratory courses are usually designed to provide experience in experimental techniques as well as to develop a facility for manipulating raw experimental data. Computer methods can provide experience in the latter phase of laboratory work but do little with respect to the former unless the computer is treated as a lahoratory tool interfaced between the student and the experiment. Basically, simulation programs can be designed to have a student engage in all the decision-making he or she normally would do in a real experiment, i.e., collect data and draw conclusions based on the data. I t is oossihle to introduce exoerimental errors in the results of computer-simulated experiments which reflect the accuracy expected from the equipment normally used in the lahoratory
as well as gross random errors. Thus, the students' experience in manipulating experimental results can he extended by simulating experiments that (a) might be conceptually simple hut which reauire annaratus too c o m ~ l e xfor them to ma.. nipulate a t a given educational level (e.g. atomic spectroscopy, X-ray diffraction at the general chemistry level), (h) consume a disproportionate amount of time if performed in their entirety, (c) are potentially dangerous, and/or (d) involve expensive equipment or chemicals which cannot be supplied for large numbers of students on an individual basis. Simulated experiments can be used in various ways, e.g., as extensions of laboratorv work as well as suoolements to conventional .. lecture material. I t should be pointed out that the terminals on which students might pelform simulated experiments need not be located in a lahoratory; they may he placed in study rooms, library carrels, or even in dormitories. Further, simulated experiments need not be performed a t the conventional lahoratory periods, nor do the programs need to he available in an interactive mode. Thus, a part of a student's laboratory exnerience can be nrovided in a more flexihle manner than is now possible unier the logistic constraints imposed by conventional lahoratorv work. The savings " in costs for eauioment .. and chemicals using computer-based methods is obvious. Homework Problems Homework ~ r o h l e m shave been used traditionallv to orovide the student with practice in prohlem-solving, but there are several difficulties with such stratew. . First, grading and rerord-keeping h e n m e important considerations in classes with large number of n r l m t s . Second, feedback on problems (grading) is generally slow and individual error analysis virtually non-existent when a large number of problem sets are hand-graded. Many of the programs written for tutorial/drill mode or laboratory simulation contain drivers or subroutines well suited for generating prohlems. Separate homeworkgenerating programs have also been developed as well as programs to grade the homework, for a program that can generate problems can contain information on the details associated with common student errors. Thus. i t is nossihle to give not only full credit for a problem, hut a ~ s dpartik credit if intermediate steps are correct hut the final answer is wrong. In addition, such grading programs usually incorporate suhroutines that automaticallv vield aopropriate statistical analysis of the student's p&f&manc~'onindividual problems. ~
Examinations An important element uf cnmputer-hased techniquesis the develupmenr ut prngrttm%and data bases that generate examinations. Thc ah:lity to generare a large number of exsminationi that are statiitically t:qutvalenr gives the instructor :I wrv mwerful rearhin. ~lt!ricc.\Vith such nrwrams availahle,"it'is possible to create self-paced courses for relatively large numhers of students; such flexihle courses generally depend upon the availability of a "readiness test" on a student-demand basis. Innut of the marked examinations into the grading program can he either in a hatch mode using iuexpensive mark-sense readers or interactively. The latter operation permits immediate feedback to the student. I t is apparent that for larger numhers of students at various points in a self-paced course the logistics of creating, administering, grading, and maintaining security for a large number of difierent examinations becomes virtually unmanageable using conventional methods. Computer-based methods not only but they can also expedite all aspectsofexaminatiun-t>tking, tncnrp(rate relatively sophistinlted record-keeping and stntistical rourinri a i t h little additional difficult\.. Most of the successful applications of computer-based methods have occurred at the learninn-teachine interface. Proaams either h e l ~ students learn and/& expaui the functionsof teachers. ~~
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S u ~ c v i s f ~methods tl are those in which curnputing is .;upnormal reaching functi~msrather than thusr in which attempts are made to &y to replace them p l ~ ~ m m t10 u lthe
Of Babbages and Swings Derek A. Davenport Purdue University West Lafayme, IN 47907 The time has come our Chairman says To talk of many things, Of eherubims and SERAPHIMS, Of Babbages and Strings, And if the Apple's worm is bit, Will we he underlin~s? . Indeed will we be there at all, When to the Dean's delight, Professors are superfluous And students spend the night Transfixed before their tiny screens, Preprogrammed to be bright? The laboratory a cenotaph, The T.A.'s on relief, No need for books or chemicals, Savings beyond belief. 0 brave new world of Academe, All Indians, no chief! Yet students' minds take random walks, Spelling tends to frolic, And chemistry most often is More concrete than symbolic; So may they both small quarter give, To simple two-bit logic! But if the" mind their o's and a's. Upon the college scene, Their gentle flips and muffled flops, Echoing o'er the green. For unlike aging Faculty, Whose lids are apt to flip, Their patience is quite awesome, Their floppy discs don't slip, So let us hear a "euarded cheer. Hip, chip, hooray, hip, chip! To answer the first three questibns in Chuirman Moore'i little red catechism: "no. nu, and amin. no. What I tell vou three times is true." Should Computers Replace Professors? Only in selected cases, hut the AAUP won't allow even those few replacements to occur. If only the pious hope "anyone who can he replaced by a computer, should he" were true! As for the competent majority, the teaching professoriate will happily remain indispensable in the computer age. Man is, after all, a tool-making animal and the computer is merely the latest tool, though just possibly one of an entirely new kind. Around 1450 Johann Gutenherg was advanced 800 guilders for the development of new "tools" and within a few years those tools had produced his unsurpassed Latin Bible. In the case of computers in chemical education, even Stan Smith has not . .."though vet sot nast "in the heeinni u " to listen to some of the apocalyptic advertising one might think we had already programmed the Book of Revelations. Mv is best stated " "~reiudice . in the language of Pascal. "L'homme n'est qu'un roseau, le ~ l u faible s de la nature: mais c'est un roseau ensa ant" which 'for those still struggling with enhasic ~ n ~ l i may s h be translated as "Man is only a reed, the weakest thing in nature; hut he is a thinking reed." I t might however be well to remember that L. S. B. Leakev has claimed that in the hands of the meat . apes a reed is one bf the most useful of tools.
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Volume 61
Number 1
January 1984
33
