From Videotapes to Videodiscs: From Passive to Active lnstruction Arlene A. Russell University of California, Los Angeles, Los Angeles, CA 90024 Pre-recorded television nroerams have been used in chemical education for almost 2Cyears (1-3). Although much of the earlv work in this field was done in the United States. Canada, and Hritain, workshops held last iummer at the 1n: ternationnl Chemical Education Conference at Montnellier. France, suggested that the use of tele\.ision in chrmirh rducation has spread around the world. One of the g ~ ~ aofl st hrse workshops was, therefore, to develop a continuing netwwk of individuals who could keep each other informed about the state-of-the-art in this area. The chemistry teachers who attended these workshoos in Montpellier were almoat exclusively interested in the use of television at the collrge and uniwruity level. Their work in videotape at the present time is f(r:us&l on the arras of prelaboratory instruction and supplrmenting the lecture.
U s e s of Vldeotaped Instruction in the Laboratory (4-6) Particularly in developing countries, televised productions are seen as a way t o provide instruction on equipment that is otherwise not available to students in any form. Regardless of the country, when limited amounts of expensive equipment are available, the need to prevent damage to this equipment is paramount. There is, therefore, a universal use of television to demonstrate accurately, clearly, and concisely the proper use of laboratory equipment. Alone with relievine the concern for the eauinment. videotapeidemonstratiok of laboratory procedtkes are seen as a solution to the problem of diverse laboratory instruction when large classes are taught by instructors with variable teachine skills and backerounds (6). A second problem thachas arisen'from the increased access of oeoole to hieher education is the varied or often nonexistent labora.u~rytikiiis of students entering college. Several months ago Professor Tongwen Hua of the Chemistry lkpartment of Reijing (Peking) University remarked tn me that the practical laboratory aspects of high school training in (.'him were heinr neglectedbeiuse compkitive universitfidmission was basea on written examinations only. We have seen the same effect in some Advanced placement courses in California high schools. As a result, the primary use of videotapes in chemical education has become the "how-to" of the laboratory. There are three different kinds of pre-lab instruction programs. Some programs focus on a particular set of instructions for a specific experiment. Others can be used for a variety of different experiments but still focus on an individual piece of equipment. A few attempts have been made to develop "generic" pro-
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Journal of Chemical Education
grams that teach techniques independently of a particular piece of equipment.
Uses of Vldeotaped Instruction in the Lecture Videotapes were once used to replace the live lecture. With the exception of the program developed a t the University of Illinois (7-9) where videotapes are used to present lecture material in small discussion sections, few institutions still operate this way. Videotapes are still used in the classroom, but now they are more often used to supplement the live lecture. Indeed, the second major use of videotapes in the US. is to show lecture demonstrations and lecture experiments in the live lecture. There are several advantages to pre-recorded videotape demonstrations and experiments. 1) Thedemonstrations always work. 2) The time the drmunstratim will tlke is known in advance. 31 The useoftime-lnpse~hoto~ravhvcan drasticallvshorten the . . . time a demonstrat& takes. 4) Demonstrations that occur on a scale too small to be seen in the live lecture ran be magn~f~ird by clase-focustechniques. 6 ) Demonstrarions rhat are too dangerous for the lire lerture can be lilmed ourtlide the classruom. ~~
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In this format an instructor usually lectures to a certain point, stops, shows the demonstration, and then continues with a discussion of the demonstration just shown. Although the visual material is recorded rather than live, the technology can be almost transparent to the student. This is particularly so when videotape players under the control of a hand-held microprocessor are used. With these units the microprocessor can be programmed before class to show segments of material in any predetermined order. When the equipment is set u p and the visuals are selected nrior to class. the time for transition from discussion to demonstration is minimal, and often less than the time required for live demonstrations. At the University of Illinois this technique is used to present lecture demonstrations and lecture experiments in the discussion or recitation session format (10).Prior to class the teaching assistants are riven a list of the locations of the relevant segments on the tape so that they can quickly locate the desired demonstrations or experiments. Facilities for Produclng Videotapes In order to develop videotaped programs chemists often have to be very resourceful. Frequently, they have gained access to the equipment in public broadcasting studios, or
small local television stations. Still others have developed studios on their own campuses. A less expensive optionhas been the use of existing campus facilities dedicated to fine arts or media departments or instructional resource centers. Over the years, the enthusiasm of chemists for stardom has waned and a common style has emerged. This style employs an off-camera narrator to describe the procedure being shown. Extreme close-ups using a camera angle that showsthe perspective the student would see is the most frequent format for these programs. Serious efforts are madeto keep the programs as short as possible, usually under 15 min (11). Facilities for the Use of Videotapes Once a commitment has been made to use videotaped materials, instructors have had to consider mechanisms for viewine these oroerams. The simnlest. . . cheaoest. and most c o m m i facilit; is cart on wheels with a videdtape'player and an elevated television monitor. These set-ups can he easily moved to the lab or classroom when needed. The time when the program is shown is under the instructor's control and the program can either precede or follow a discussion of an experiment or demonstration. By showing the program in class, the instructor guarantees that a11 the students have been instructed in the oarticular orocedure. Difficulties are encountered, however, when the class is large or when more than one class needs a particular program or the equipment a t the same time. This problem can he overcome with a closed-circuit television system (12). Many buildings designed in the last 20 years have had this capability huilt in. Usually monitors are placed in the laboratory or lecture hall above the heads of the students. At the University of Melbourne in Australia, Norman Olver designed a facility in which he set the monitors on the side of the room at the eye-levelof the students when they are seated at their lab plac& (13). A t hird mechmism for showing the videotapes is to put the oromams in a learning resource center or an audio-visual libra& where studentscan view or review the programs on an individual basis as often as they wish. At the University of Beijing, for example, this is the only place where viewing facilities are availahle. In the United States, faculty have typically chosen to delegate to others the everyday duties-of maintaining videotape equipment and programs. Learning Resource centers and iibraries logicd; assume these reponsihilities. The viewing of programs can still be a course requirement with this type df airangement. More often, however, students are simply advised to view the progams hefore coming to class. Although students may not have the opportuity to ask questions if they find the programs ambiguous, there are definite advantages to this type of arrangement. Since Resource Centers tend to he staffed a large portion of each day, students can view programs a t their own convenience when they are ready to learn the class material. Furthermore, this arrangement tends to free the lab time for actual experimental work.
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Videodiscs Once a learning resource center is set up for individualized instruction the nossibilitv for trulv interactive video instruction becomes availahie. Adding interactive instructional materials on videodiscs to a resource center is a relatively minor change in terms of either policy or cost. I t is a profound chance in the instruction available to students, however. The dit'feFenre between interactive videodiscs and videotape is the same as the difference between CAI and a textbook; the student becomes actively involved in the learning process. At the present time there are three prototype interactive videodiscs in chemistry; two were developed a t the University of Nebraska last year, and the third a t UCLA a year earlier. Each has been used to explore the kinds of interactions pos-
sible with video instruction that are not easily conveyed by other means. The UCLA disc was designed as aprelaboratory assignment for students in general chemistry. We selected one narticular exoeriment because we knew that students had varying degrees of difficulty in understanding the theory, the lab orocedure. and the analvsis of the data in this experiment. I t was, therefore, an ideal experiment for testing an interactive svstem. At this point it may be helpful to discuss the different kinds of videodisc svstems. The recent demise ot'the RCA videodisc system will hsve no effect on the use of videodiscs in education. The Pioneer laser videodisc svstem is the only videodisc player in this country that lends itself to interactive instruction. There are three levels of programs (each with different hardware requirements) that can he developed for videodisc. Level one programs are intended for the home consumer. The only interaction pwsihle at this level is a search command, not unlike the capabilities of the videotape system used for lecture demonstratibns at Illinois. The second level of program requires an indujtrial videodisc player. With this type of player there is a huilt-in microprocessor that can read digital information encoded on the disc. If the program is bigger than the capacity of the microprocessor, sereral dumps can he stored on a disc, and the program can call up whichever one is needed. Even when a dump is called up, the time to locate the necessaw information is no more than a few seconds. When we were desienine " " our disc we chose to use this level so that the hardware to play the disc was no more complicated than the hardware for the videotaned . oromams with which the students were already familiar. In this program the interaction with the student has been huilt into the videodisc program. The student can only resoond to multide-choice questions on level 2 programs. This does not meanthat indivihualized instruction is;mpossihle, however. The program can ask the students many questions. The answer the student gives to a question then determines which section of the nrogram is shown next. For example, a t the end of the ~ ~ ~ ' ~ - p r owegave & a m the student the option of taking a quiz. The parricular quiz the student is given depends on the sections he or she has seen earlier in the session. Thus, the quiz is tailored to the individual's instruction. The third level of program availahle on videodisc requires anexternal computer as well as the videodisc player. The two videodiscs developed a t Nebraska last year are level 3 programs. Whereas we were developing materials that were to supplement the regular lab course, their progams were designed for students who might not otherwise have access t o laboratory. Within the traditional university curriculum there are often courses for which a lab would he useful hut not oossihle due to a lack of facilities. Also. the issue of the "distant learner" is a continuing challenge in this country. The videodiscs from Nebraska can serve as exoeriments in which the students are actively involved in ohtain'ina the data. One of the nrwrams is called "Titrations." In this vrorram a student c& sekct the kind of titration he or she wan& torun. The sample is weighed out on a halance (or pipetted if a solution) and then placed under a huret. The huret is then washed, rinsed. and filled. The titrant can he standardized for thestudent or the student can select m d o that first.The huret can then be drained. read, and indicator can he added to the flask. T o simulate the titration, a game paddle is used to control the stopcock. By turning the dial the stopcock is opened and closed. On the screen there is a schematic diagram of the position of the stopcock. Titrant can he allowed to drain freely or be added by drops. A drop can also he rinsed off the tip of the buret. When the student wants to stop and read the huret, the dial is closed and the side button pushed. At this time the screen turns to the huret and the gradations can he read. T o complete the titration, the data are recorded on a worksheet and the observations and calculations are checked. The stuVolume 61
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dent's data and calculations are then checked against the progam's data and answers. As in a regular experiment in the laboratorv. additional titrations can be run for the standardization. When the student has finally completed the experiment and leaves the proeram. the disc resets itself so it is ready for the next student. ' Conclusions
In reponse to laree classes and weak student oreoaration. chemistry instruct& around the world hav' introduced videotaped materials into their lecture and laboratorv teaching. Many of these programs use sophisticated techniques to show the students procedures better than an instructor can in the classroom. But, videotape can not respond to the many differences among the students in large classes. The three chemistry videodiscs that have been developed, however, suggest that this new medium has the potential to address these diverse student needs. In the next few years, the development of more videodiscbased Dromams nromises to brine instruction back to the individual &den< As material in &is medium hecomes easier t o develoo more discs will be oroduced. Alreadv several projects h e on the drawing board. When thew rnatkials are available we will haw come full circle. DesoiLe laree classes. varied instructors, and weak student pre
