and F. A. Matsen The University of Texas Austin, 78712
I I
Computer Augmented Lectures
We have developed a technique for direct computer augmentation of lectures (CAL) suitable for large lecture sections. We empl0v . . our central computer linked to a CRT console in the room, whose display is projected onto a large screen. The principal features of CAL are 1) Low hardware cost per student: by requiring only one remote terminal for large numbers of students, CAL shares the cost per student both far hardware and computer time in the most economical way. 2) Simplicity in programming: because of the live instructor interface between students and computer, the program does not require internal loops to correct input erron. Instructors are especially goad at this. 3) Interrupt capability: the instructor may interrupt at any time to interpret and explain. 4 ) Transferability: because each module (or program) is separate, and since the programs are also very simple, CAL modules are easily transferred from one college to another. In addition, the small hardware requirement permits use of CAL at schools where alarce numbrr of remote termmala are not awdable 5 ( ; a d tnrcrncttre mp0h111rt~s once the loyistics haw bern eatabllshrd.. . wohlems mil) br submitted and formulared fnm ihr floor. "What if" questions canhe answered quickly and completely. 6 ) Compute power: as a consequence of the speed of machine calculations, many related problems may he solved during a single lecture so that the student acquires quickly a wide range of experience, operational understanding, and even intuition. One can thus illustrate rather than merely assert the generality of the procedure being presented. 7) Recordability: the display for each lecture or problem can he recorded for playback an cassette tape, punched paper tape, or video tape providing: (a) backup in the event of computer failure during lecture, (b) opportunity for review by individual students, and ( e ) transferability of the lecture toother colleges. 8 ) Standardization: it can standardize the general approach among different lecture sections of the same course. 9) Superior display: the instructor is released from the hlackhoard, making it easier to communicate. 10) Dynamic presentation: the student's attention is focused on the projected material because of something like the "follow the bouncing ball" syndrome. 11) Flexibility: since each module is independent, any course may use those which are most appropriate and in any order. 12) Utilization of instructor personality: the instructor retains control of the classroom situation. He can teach at a rate compatible with student capabilities and inject his own personal experiences and humor into the lecture. Unlike most computer learning techniques, the computer in CAL assists rather than replaces the teacher.
reduced to a minimum and the full computational powers of the computer are utilized to treat quickly a large number of problems of the same general type hut of varying complexity. Now the entire range of applicability of the theory may be investigated by immediate exact calculation. An outstanding feature is CAL's ability to respond almost immediately to questions posed by the students. CAL: Examples
CAL was originally developed in order to assist in the teaching of modern theories of chemistry1 (several of the topics are listed in the table, modules 1-9). These topics are usually omitted in introductory courses, but nevertheless form a large part of modern chemical research. For this reason we have offered over the past seven years a freshman course entitled "The Vector Space Theory of Matter" (VSTM) to above average students a t The University of Texas a t Austin. Because of the success of the technique in presenting these topics we have begun to apply it to the standard large sections of general chemisCAL Modules 1. Atomic Theorv* 2. Huekel Theory* 3. Crystal Field Theory* 4. Nuclear Magnetic Resonance'
5. Eieetron Spin Resonalce 6. Vibrational and Rotational Spfftrowopy 7. Fine Structure 8. Nuclear Theory 9. Related Mathematical Tutorials,ineluding
a. Determinsnts b. Eigenvalue-Eigenv-tor computation* 10. OH* 14 modules) 11. i'itration*
12. Kineties 13. Equilibrium Calculation
We operate CAL in two fundamentally different modes, a n introductory tutorial mode and a compute mode. The tutorial mode employs a scenario similar to conventional CAI, but with the advantage of the instructor's presence for explanation. We employ this mode to provide a step by step introduction to a subject, illustrating it with several simple examples. Throughout the tutorial numerous holds are provided so that considerable time may be spent explaining the steps in the problem. After several tutorials have heen completed and the hasic steps mastered, we switch to the compute mode. Here input and output are 1 Matsen,
F.A,, J. CHEM. EDUC., 49,794 (1972)
192 / Journal of Chemical Education
W . A.
Seitr working with the Huckel matrix for the cyciopropenyl radical.
trv. In the fall (1972) we taught the elements ifHuckel mkecular orbital the& in the-general chemistry course of 250 students using CAL. The students saw the aoolication of modern theory to problems in chemistry without becoming hogged down in mathematical detail. After two computer augmented lectures a student commented that "this stuff is sure a lot easier than pH." In the last class meeting we therefore presented a review of p H and titration ;sing CAL. In 45 min we were able to compute and display titratiou curves for strone acid-strong hase. weak acidstrong hase and diprotic aiid-strong base for arbitrary dissociation constants and initial concentrations, thus reviewing without extensive computation many important concepts. Following the course an evaluation of student reaction to CAL and Huckel theory was made. The most frequent complaints concerning CAL were 1) projection clarity, 2) presentation speed and 3) room darkness. All of these problems have presently been solved.2 We currently employ a high resolution rear-screen projector which has near perfect clarity and can he operated with room lights on as shown in the picture. In addition, the data rate for display of characters on the CRT has been reduced from 30 to 10 characters per second. With respect to the Huckel theory presented by CAL, the response was nearly 100% favorable, indicating both interest in and ability to learn mode m chemical theory. CAL has thus provided access to this important area of chemistry by overcoming the mathematical details and concentrating on methods and concepts. Development of CAL modules for kinetics and equilihri.um calculations is currently in progress. In addition, plans are heing made to use the CAL module for nmr to introduce the freshman to this important tool in modern chemistry, and to illustrate to him the constructive interplay of theory with experiment. Without CAL such a program would be virtually impossible for large classes. Nevertheless, insofar as our introductory courses confine themselves only to simple chemical problems, they do not introduce the chemistry of today. CAL thus not only increases the depth to which material may he treated, hut increases breadth also. Comparisons
In the last several years computer.learning techniques have been widely applied, primarily to individual student interaction with a teaching program. Such computer assisted instruction (CAI) has provided a way to allow students t o learn a t their own rate independent of the average student's ability. Unfortunately, CAI is very expensive both in terms of hardware (paper, teletypes, etc.) and in terms of computer usage. Logistically, the problem of scheduling teletype use is quite difficult. Also, since flexibility in CAI requires sophisticated program branching, CAI programs are very complex and consequently not easily transferred between schools. While such individualized instruction with highly flexible programs on high speed computers is indeed useful, there would seem to exist a demand for applying the computational power of standard computers to teaching situa-
tions in a more economical and transferable way. CAL provides such a way. Monetarily and logistically the ohvious advantages of replacing 250 individual interactions with a single CAL lecture cannot be overemphasized. CAL programs are vastly simpler than CAI since all branchine for exnlanation is done hv the instructor.'thus releasinguthe computer for the jod of computing; This simolicitv oermits easv transfer of all CAL modules. With the increase in demands put on current computer facilities, the advantages above should become more important. Besides these technical features, CAL has several teaching advantages. One such attribute is real time linear development of lecture material, which has long been recognized as an advantage of hlackhoard use over slide display. CAL maintains the real time relationship to the ideas being presented releasing the instructor from the hlackhoard and improving the clarity and accuracy of the lecture. Also. the flexihilitv of CAI. for immediate response to student questions cannot he obtained via film or slide disolav. oro. .. and cassette or ounched tane recordine". vides a replay capability for student review without group presentation. The additional flexibility due to the immediate computer-power available in CAL can extend ordinarv lecture material into new. more comolicated situations as was discussed earlier.'Finally, the flexihility of CAL due to instructor teaching stvle and oersonalitv oermits a variety of learning exp&ences. In contrast to CAI or even video display of CAI output, CAL provides only compute-power and the nucleus for a lecture instead of rigidly locking in on a single teaching pace and method. The attendant flexibility for module use in classes with widely differing aptitudes and backgrounds has resulted in our use of the Huckel module for both a freshman chemistry class and an NSF summer short course for college and university chemistry teachers. While CAL was developed for courses in chemistry, the technique is applicable to other subjects. Currently applications to introductory physics are heing investigated a t The University of Texas by Professor J. D. Gavenda. In addition, courses in business, statistics or computer science could also benefit from CAL. The table lists the CAL modules currently in use or under development. Modules in operation are marked with an asterisk.
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Acknowledgment
The authors acknowledee the suonort of the ComouterBased Education project'at The university of at Austin suooorted bv the National Science Foundation. We especkly acknowledge the expertise provided by Mark T. Muller whose assistance in planning and ohtaining the necessary technical equipment made this work possible. Full details on the equipment specification and vendor source may he ohtained from Project C-Be, Mechanical Engineering Department, ENL 413, The University of Texas at Austin, 78712.
exa as
2 Further discussion of technical details will be given elsewhere in a later paper.
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