AN EXPERIMENT IN TEACHING GENERA CHEMISTRY BY CLOSED-CIRCUIT TELEV
figure
1.
The Chemistry "Originating Room." Showing t h e Overhead "Scoop" Lights and Two of the Four Side Lights. Located in t h e Audience. the Other at t h e End of the Lecture Table.
INTRODUCTION
It is well known that enrollments in colleges and universities are due t,o increase tremendously in the next 10 or 15 years. Knowledge that this expansion in student bodies mill be experienced quite generally, especially in the public institutions of higher education, has led to studies of possible solutions to these problems of expansion before they materialize. A possible partial solution to the problems of increased enrollments and teacher shortages lies in the use of various communication devices for extending the teaching of competent instructors to larger audiences of students. A promising device for mass communication is that of television. Considered merely as a means of communicating both by sound and hv sight. Presented as part d the Symposium on The Use of Closedcircuit Television in the Teaching of Chemistry before the Division of Chemical Education a t the 128th Meeting of the American Chemical Society, Minneapolis, September, 1955.
One Camera I.
GRANT W. SMITH The Pennsylvania State University, University Park, Pennsylvania it would appear to deserve careful, objective evaluation for educational purposes. The present paper describes an experiment which was carried out in the spring semester of 1955 by the Pennsylvania State University with the aid of a grant from t,he Fund for the Advancement of Education. The lecture part of a second-semester general chemistry course and two complete psychology courses were taught by use of closed-circuit television. As far as we know, this project repreeents the first in which whole courses or segments of courses have been taught by dosed-circuit television on a controlled euperimental basis for a full semester.
258
PURPOSE OF THE STUDY
JOURNAL OF CHEMICAL EDUCATION
students on experiments related t o the lecture m a t e The general purpose of the study may be stated in rials. About two-thirds of the laboratory work is broad terms as follows: to determine the relative effec- spent on semimicro qualitative analysis of selected tiveness of the use of closed-circuit television in the metal ions. An entire lecture group meets simulteaching of unmodified university courses as compared taneously in the laboratory. Graduate assistants with conventional methods of teaching in the class- supervise about 25 students each, and a senior staff room. Television was not t o be considered as other member supervises the over-all group of students and than a means of communicating normal good teaching assistants. Nearly all students who take "chemistry 2" take to groups of students. In other words, it was planned to adapt television to the course, not the course to further work in advanced chemistry courses. I n general, they are students in scientific and pre-professional television. To carry out the general purpose, several studies curricula, such as chemistry, chemical engineering, pre-medicine, and the mineral sciences. Since they were required: (1) Study the feasibility of the use of moderate- have just completed the first course, "chemistry 1," quite complete data on their previous background in cost TV equipment for instructional purposes. (2) Determine the acceptability of this type of chemistry are readily available. Since no attempt was made t o use television in the instructional medium t o the students, the faculty, and laboratory or recitation groups, the possibility of the administrators of the institution. significant differences between televised and (3) Determine both the limitations and the ad- finding control instruction is reduced. It must also be obvantages of the use of closed-circuit television in inserved that learning may occur not only as a result of structing various types of courses. lecture demonstrations but also from the textbook, the laboratory exercises, and the recitation periods with DESIGN AND PROCEDURES IN CHEMISTRY respect to which all sections were treated alike. The experimental design in the chemistry study was The students in lecture sections were divided into planned to give as good a comparison as possible be- three groups, one of which was taught in the originating tween sections taught with the use of television and room, while a second (divided into four subgroups) those taught conventionally without television. Both received the lecture demonstrations over the television the student groups and the instructional procedures systems in the receiving rooms. The third group, were set up so that the principal variables were in the which constituted the control group, was taught in the means and conditions of communication, not in course originating classroom with no television equipment content, instructional staff, or method of presentation present. of matekals. Random assignment of the students t o the three exTo understand the experimental design, it is desirable perimental lecture groups was impossible due t o the t o oresent here a brief descri~tionof the course under nature of the course, so a matching procedure was used observation. The chemistry course selected for the t o obtain equivalent groups based on two principal closed-circuit television study is the second semester of factors: (1) curricular interest, and (2) grades in the one of the two principal introductory courses offered preceding course in chemistry. by the department of chemistry. It is a five-credit ASSIGNMENT OF INSTRUCTORS course which consists of two lectures, one recitation, The instructors who were to participate in the teleand two laboratory periods of three hours each per week. The chief factors influencing the selection of vision project were selected on the basis of recognized this course for the study included: the large number of competence and experience and also on their interest students involved (about 450), the uniformity of in such participation. The three lecturers were men who had had previous laboratory conditions and location, and an experience of several years in the course using the same textbooks. experience in lecturing for this course.2 Their responsibilities included: Only the two weekly lecture periods were directly (1) The planning- of the order of mesentation of concerned with television presentation. Lecture sections normally involve groups of from 120 t o 200 stu- mitirials. ( 2 ) The preparation of the individual lectures and dents in a large lecture room. New material is predemonstrations. sented and lecture demonstrations are used frequently. (3) Participation in planning sessions and regular The lectures are considered to be the core of the weekly staff meetings. course. (4) The primary responsibility for the preparation Lecture sections are split into recitation groups of of the three monthly examinations and the final exabout 25 each which meet once a week with senior staff instructors. New materials are not ordinarily pre- amination. (5) Observation and reporting of reactions of sented in recitation; instead, review, drill on problems, students, as well as their own reactions to the course. short quizzing on current work, and question-answer methods are used. a Besides the author, the lecturers were Professors C. G. Hsas The laboratory periods are devoted to work by the and Thomas Wartik.
VOLUME 33, NO. 6,
JUNE, 1956
Each lecturer assumed full responsibility for onethird of the lectures. They appeared in rotation; i . e., lecturer A presented three lectures to all groups; lecturer B then presented three lectures. When lecturer C had completed a similar series, A took over for his next series, and so on. The plan of operation outlined above gave assurance that each student in all lecture groups received the same lectures and demonstrations from the same instructor. It also meant that each student received instruction in the lecture phase of the course from three different experienced lecturers. In this respect the procedure differed from the conventional one, in which a given student has only one lecturer throughout the course. This plan gave each of the lecturers a period of time for preparation of his materials and demonstrations, since he was "off duty" while each of his two colleagues was presenting his series. An added advantage from the instructor's standpoint is that he was able t o observe the presentation of the other lecturers on the television screen and thus gain an added knowledge and appreciation of the procedure from all angles. Each lecturer was credited with a teaching-load equivalent to the full lecture load for the course. Four senior staff members who were familiar with the "chemistry 2" course were given the responsibility of observing in the classrooms in which the television receivers were located. Experienced instructors were selected for this purpose because it was felt that they would be best able t o note student reactions and subjectively judge the effectiveness of the presentation. Their responsibilities included, in addition t o the above, monitoring and adjusting of the receivers when required, keeping the attendance record, and filling out a brief report sheet of observations for each class period. The observers also participated in the regular staff meetings each week, and most of them were responsible for some of the recitation and laboratory phases of the course. EQUIPMENT
The following brief description of the equipment used in the project is abstracted from the complete report of the project which is now available in printed form.3 The detailed description of equipment was prepared by members of the Instructional Film Research Program of The Pennsylvania State University, of which Dr. C. R. Carpenter is Director and Mr. L. P. Greenhill is Associate Director. The IFRP group conducted the entire project with the cooperation of the department of chemistry and the department of psychology. One of the basic requirements of the current study was that "low- or moderate-cost" television equipment must be used in the interest of feasibility. The equipment should also be portable and not easily damaged a CARPENTER, C. R., L. P. GREENHILL, ET AL., "An Investiga, tion of Closed-circuit Televisionfor Teachine Universitv Courses" (Project No. I), The Pennsylvania ~ t a t e ~ ~ n i v e r s iJuly t i , 31, 1955, 102 pp.
by semiskilled operators. These considerations pointed to the use of equipment designed around the vidicon television pick-up tube rather than the standard studio equipment which uses the image orthicon tube. Equipment built around the vidicon camera tube has a number of advantages and disadvantages when compared with image orthicon television equipment. Some of the advantages are: (1) Lower initial cost. (2) Lower maintenance cost (the vidicon tube costs about one-third as much as the image orthicon tube and has a very much longer lie). (3) Operation and maintenance feasible for semiskilled personnel. (4) Portability. (5) Less easily damaged and less subject to "burning-in" by bright objects. (6) Uses less costly 16-mm. camera lenses. (7) Gives good gray-scale reproduction. The principal disadvantage of the vidicon equipment is its lower sensitivity t o light as compared with the image orthicon camera. Standard Westinghouse 24-in. table-model receivers were selected. These proved t o be very reliable in operation, and were particularly suitable because of their rugged all-metal cabinet. Aluminized picture tubes were found to provide a more brilliant picture than the standard tubes, and were generally used. One 24-in. receiver was located at the front center of each classroom, serving about 30 students. In the subsequent project (fall, 1955), two receivers were used in most of the receiving rooms for up to 50 students. Figure 2 shows one of these later systems. It was found after two or three weeks that the original 5-in. speaker located in the side of the cabinet did not give satisfactory sound level and quality. Accordingly, in each of these receivers the 5-in. speaker was replaced by an 8-in. speaker in a small baffle box, mounted underneath the receiver and directed toward the class. I n order to locate the receivers at a convenient height and t o make them easily movable and accessible for servicing, special light-weight metal stands were designed and constructed from 1-in. angle iron. These stands had adjustable legs so that the height of the center of the screen could be adjusted between 4 ft. 6 in. and 5 ft. 6 in. The dimensions were such that, with the receivers in position, the stands could be wheeled through standard classroom doorways. Reflections of the room lights from the faces of the receivers presented an initial problem. After some experimenting, several steps were taken to reduce or eliminate this difficulty: (1) Hinged masonite hoods which projected forward about 15 in. over the top front of each receiver were installed. (2) Each receiver was tilted forward by placing a 4-in. block of wood under the rear edge. (3) The window shades were usually drawn and part the lights were used. The Dage television cameras, two in number, were lc-
JOURNAL OF CHEMICAL EDUCATION
260
!!
-- .."
10 foot-candles. A lighting pattern was worked out using seven incandescent lighting units: three floodlights ~"scoops") and four spotlights. Two spotlights of 2000 watts each were located on the side walls, in front of the instructor's table,to provide"mode1ing" light of fairly high contrast. ; Two similar units located nearer the front wall gave side and back light and lighted blackboard and table. These spotlights were mounted abo& 14feet above floor level. The three 1500-watt "scoo~s" were - I mounted on a i-in. ~ i
-
1
Ii -
z.
A
F
~
e
~. ~ v r r e n t ~~ ~ ~ eini chemistry ~ ~ ~~ s" ~ e s e i u~i n g~ o o r n '=s used y I F ~ I~19551 ~ .
~ ~ be raised ~ or lowered by a windlass. (See Figure 1.)
cated in the fourth r o r of seats in the chemistry lecture auditorium. From this position the full length of the THE TECHNICAL STAFF blackboard and lecture demonstration table could be For any sustained experiment involving television covered without obstruction. The camerae and op- equipment, it is necessary to have an adequately trained erators did not obstruct the vision of the students in the staff of technicians and operators. If closed-circuit lecture room. The two cameras were mounted side by television is to be feasible for economical college or side, and each was equipped with three lenses on a university instruction, it is essential that such staff turret (I-, 2-, and 3-in. lenses). A 4-in. lens for ultra requirements be kept to a working minimum, and that close-ups was included in the equipment used in the personnel available on campus be used so far as possible. fall, 1955. With this arrangement it was possible to use one Our technical staff consisted of both regular staff camera for long shots and the other for close-ups, or to members and students. Members of the Instmctional have one camera on while lenses were being changed on Film Research Program at the University are highly the other. I n addition, the availability of two cameras versed in matters of camera operation, lighting, and provided a safety factor in the event of a breakdown other skills required for filming and projection of effecwith one camera. tive teaching procedures. Student engineers, both Control equipment was conveniently located in a graduate and undergraduate, were used for testing and small room immediately underneath the elevated seats maintaining equipment as well as in operational phases in the lecture room. The control eqtiipment, consisting of the work. Several key men spent some time a t the of two camera controls, switching unit, audio-video factories of the equipment manufacturers t o receive mixer, synchronizing generator, power supplies, and a special training. I n addition, the services of consultmonitor, was mounted on a simple type of console. ants from the manufacturers were available and engiA small chest microphone was used by the instructor. neers from near-by television stations were brought in This was an E.Iectro-voice Lavalier type dynamic for technical aid on one or two occasions. microphone of low impedance. It was inconspicuous For actual operation in televising the instruction, since it could be worn under the necktie, allowed free three men were used as minimum staff. These were movement, and gave a uniform level and high quality the two camera operators, usually students with a few pick-up. hours preliminary training, and a control operator, usuWhile a 24-in. receiver was available to the instructor ally a trained member of the I F R P staff. The control t o see how his demonstrations appeared on television, operator was in continual, two-way communication its use was found unnecessary and was discontinued. with the camera men. He was responsible for seeing As a result of early experimentation with the vidicon that a good picture and sound were relayed t o the cameras, it was found that between 150 and 200 foot- receiving rooms at all times. Camera angle, size of candles of illumination were desirable for optimum viewing field, and correct centering on field were items quality pictures using a lens aperture of f/2.8. Orig- subject to his judgment and guidance. A student engiinal room lighting in the lecture room was only about neer was usually on stand-by duty.
~
e
VOLUME 33, NO. 6, JUNE, 1956
There were no preliminary rehearsals of the lectures before the cameras. Usually the instructor would brief the operators a few minutes before class concerning any demonstrations that required careful timing or special features that needed to be caught by the camera. For example, if soap bubbles full of hydrogen were t o be ignited in mid-air, the cameraman had t o be aware of the fact or he might leave the camera on the bubble-blower instead of the ascending bubbles. Freqnently the instructor would indicate what t o look at, emphasizing the important points t o be observed. The cameras acted merely as onlookers and picked up what normally occurred and was visible to students in the classroom. As a result of the semester's experience it is clear that for certain operations one camera should be located close t o the demonstration table. This takes full advantage of one of television's greatest potentialities, the ability t o give a close-up view. This procedure was tried out during the final chemistry lecture demonstratiou with good results. It was possible to show a Wilson cloud chamber and the operation of a Gieger counter in such a way that students looking at a t e l e vision receiver could see much better than students actually looking at the demonstration. (During this last class receivers were also installed in the originating room so that the students there would not be a t a disadvantage!) Slides were used from time to time and these were satisfactorily televised directly from the screen in the originating classroom. I n practice it was found that a few special modifications of instructional procedures were needed: (1) Use of the blackboard. It was found that f o r writing on the blackboard to be legible on the television screens the instructor should use only one panel (5 feet wide) a t a time. If more than one panel were covered the reduction in size of the image on the television screens made reading difficult from the t e l e vision receivers in classrooms. It was also found that legibility was greatly improved if a soft grade of chalk were used. ( 2 ) Avoidance of pacing. Instructors who were accustomed to pace backwards and forwards were asked t o reduce excessive movement. (3) Checking demonstrationu. When there was some doubt as t o whether a demonstration would be visible on television, it was tried out ahead of time t o see how it could best be picked up by the cameras. This applied to perhaps five per cent of the demonstrations. When actual colors of materials were considered to be of crucial importance; samples in test tubes were circulated both in the face-to-face classes and the television classes. The engineers, camera operators, and camera controller must have a thorough understanding of the capabilities and limitations of the television system; similarly the instructor must have a working knowledge and awareness of the many elements involved in conducting a successful television course. Close co-
261
operation between instructor, camera controller, camera operators, and engineer is vital for good television instruction. EVALUATION
Ideally it is desirable to have firmly established the general and specific objectives of a course and then t o prepare measurements to test achievement of these objectives. The one general objective which could be agreed upon was that the course should teach the student a body of appropriate information consisting of facts and principles. Therefore, the main efforts of all concerned were directed toward the measurement of the learning of such information. This is usual with university teaching. For the television project efforts were made to measure as thoroughly as possible informational learning, relevant attitudes and opinions, and some general changes in interests and judgments which might be assumed to be the effects of the course. The formal meamres developed for use in the study in chemistry were s s follows: (1) Objective tests of student achievement. (2) Student reaction questionnaires designed to obtain students' attitudes t o televised instruction. Four major examinations on course content were given. Three of these were on+hour tests given a t regular intervals; the fourth was a two-hour final examination covering the work of the whole term. All students took the identical tests and examinatione a t the same time. The tests and examinations were almost entirely of the multiple-choice objective type. Questions were designed to test knowledge of facts and principles and ability to apply principles, and t o demonstrate understanding rather than simple recall, although some of the latter type were necessarily used. A significant portion of each examination dealt with chemical calculations. These tests were similar to those used in the course in previous years in both form and administration. TABLE 1 Scores on the Four Examinations in "Chemistry
2"
Total possi-
E,,
,,ble
Stand.
120
Mean ' 73.71 Adj. mean 72.25 No. students 158 81.41 Mean Adj. mean 80.39 No. students 155 Mean 73.46 72.52 Adj. mean No. students 151 Mean 67.69 Adj. mean 67.28 147
123
,
3
118
Final
102
ad
TV-
TVORb
Relia-
71.39 72.30 105 78.54 79.29 102 72.83 73.21 96 66.38 66.67 93
73.41 74.62 112 79.60 80.36 108 71.83 72.79 107 66.49 67.14 103
.91
RR'
bility
.80
.92 .89
$& ; F'?'$%;;ci, -
262
JOURNAL OF CHEMICAL EDUCATION
They were prepared by the staff members responsible for the course, under the supervision of those instructors who gave the lectures. Results of the four informational tests given in chemistry are summarized in Table 1. The reliabilities of the tests were estimated by the Kuder-Richardson Formula 21, which assumes that all questions are equally difficult. This estimate of reliability indicated how similar the scores would be if a different set of items on the same material were used. The means of the tests for each group were adjusted statistically for differences between the means of the groups on the matching variables. These were the final examination grade for "chemistry 1" and the average of the three one-hour examinations in "chemistry 1" (the first semester part of the course which all of the students had taken the preceding semester). Inspection of these figures reveals that there is no significant difference in the scores of the three groups on the four examinations. One must be careful in drawing conclusions from these results. Since only one phase of the course, the lectures, were subjected t o television treatment, the roles of the recitations, laboratory, and textbooks are not distinguished or assessed. One cannot conclude that television is better than, equal to, or worse than the conventional system. It is indicated, however, that the students' learning of informational matter, as tested, was not handicapped by using the medium of television for the lecture part of the course. I n addition t o the examinations a short questionnaire was administered t o the students in the receiving rooms in the eighth week and again in the final week of the course. Two questions were asked, one regarding learning and the other regarding interest. It was expected that the results of these questionnaires would give some indication of attitude8 of the students toward the project. The first question was: "Do you think you are learning as much over TV as you would have learned in a conventionally taught course with the same instructor?" Students were asked to check their answer in one of the five categories listed. The summarized results are given in Table 2. Since "acceptable" can logically be considered t o describe the attitude toward televised instruction of those checking "About the same," "A little more" and "Much more," most of the students can be said to have
found it quite acceptable. A very slight negative shift a t the end of the semester is noted. The second question was: "Do you think the course is more or less interesting than it would have been if taught by conventional methods and procedures?" The results are summarized in Table 3. It is interesting to note that there is a shift a t the end of the semester favoring both the first two and the last two responses. Before this report on the instructional television project at Penn State is concluded, a few pereonal comments might be in order. At the time it was originally proposed to teach "chemistry 2" lectures by closed-circuit television, considerable hesitancy mas expressed by many members of the teaching staff. It was foreseen that there would be a number of problems which could not be completely eliminated, such as the inability to transmit color and the limitations on use of the blackboard. There was also a natural hesitancy with regard t o the possible physical and psychological effects on the instructor of working before the cameras, under the bright lights, and with part of the audience located remotely. It can be said after the semester's experience that the first difficulty, absence of color, proved t o be a serious handicap incapable of elimination with the present equipment. It v a s agreed a t the start that if this or other limitations proved to be critically serious, as judged by reactions of the students and staff involved, the project would be terminated and we would return t o conventional teaching procedures. Such a critical situation did not materialize. Although the opportunity was left open for any dissatisfied student t o report to the director of general chemistry and request a transfer to a different group, no such request was made. Informal chats with students who were in the television receiving classes did reveal that the color and blackboard factors comprised their strongest objections t o this method of teaching. Absence of personal contact with the lecturer was evidently largely compensated for by the fact that the students did have such contacts in both recitation and laboratory phases of the course. The experience of teaching under the lights before the cameras did not prove to be a serious matter. After the first shock test, little feeling of annoyance was experienced, and the instructor became readily adapted to the situation. The reactions of the staff were frequently expressed
TABLE 2 Students' Estimates of Probable Learning by TV as Compared to Conventional Instruction (%)
TABLE 3 Students' Estimates of Interest of Courses by TV es Compared to Conventional Instruetion (%)
8th week
Much more A little more About the same A little less Much less
1 20 40 34 5
Final 2 16
37 38 7
Much more A little more About the same A little less Much less
8th week
Final
6 18 29 38 10
5 23 24 27 22
VOLUME 33, NO. 6, JUNE, 1956
in open discussions a t the weekly staff meetings. Early in the term, a "wait-and-see" attitude predominated. Two or three of the four receiving-room observers occasionally expressed enthusiasm for the project based upon their observation of the close attention and concentration of the students in the viewing groups and the fine visibility of the demonstrations. They observed that students involuntarily responded verbally t o the occasional questions asked by the lecturer, as they would if present in the originating room. There is little doubt that instruction of chemistry classes by television is quite feasible for the lecture phase. It has a very significant advantage in making the experiments clearly visible. If color and a large screen were available, it would be entirely practical, perhaps even quite desirable. With limited availability of high-quality teaching staff and with very large numbers of students, this method would he an important possible solution to the problem of giving
263
efficient instruction. I n our present situation, with the serious problems of lack of color and screen size, it would seem unwise to adopt the method as a regular procedure. Looking into the future, with improvements in television equipment and huge increases in student numbers, this conclusion may well be reversed. The exploratory work described in this report has helped to define several problems of instructional television which require further study. The project is being continued in chemistry through the academic year 1955-56. Several modifications in experimental design have been made in an attempt to delineate students' attitudes more clearly. I n the fall semester, 600 freshmen took the beginning term of chemistry in which the lectures were televised. I n the second semester, television will be used with large classes as a visual aid in presenting lecture-demonstrations. At the conclusion of these current experiments, pertinent findings will be reported.
