public view, and by focusing attention sharply on the crucial processes of teaching and learning.

IMPLICATIONS

It is fair to conclude that the planning and financing of higher education should include instructional television as one means of increasing the productivity of good and superior instructors. By employing closed-circuit systems, lecture halls, demonstration laboratories, and classrooms can be connected, which makes it possible for one source of instruction-a superior teacher or an instructional team-to teach very large numbers of students. Student assistants can accomplish most of the routine tasks, including the conduct of tutorial and seminar discussions. Thus television may be employed as one means of bridging the widening gap between the limited available faculties and the increasing numbers of college students. And it appears that this procedure can be used without decreasing the quality of instruction. Indeed, the possibilities exist for improving education.

The general models for using television will need to be modified and adapted to fit local needs and conditions. The number and kinds of television systems will need to be carefully selected and appropriately used for defined educational functions. Likewise, the management of instructional programs will need to be adapted to local conditions.

Instructional television, when properly and diplomatically introduced into an institution, will be accepted, in due time, by the faculties and students. As we move into the crises of enrollments, acceptability of new procedures and instrumentation will increase.

Preliminary research and development indicate that, at least, costs of instruction can be held at a reasonable level. There also are the possibilities that costs can be reduced and the balances invested for other constructive educational purposes, including the improvement of teaching.

Employment of television will not solve all the problems of higher education. It will not substitute for the teacher. It will not teach ill-prepared and unmotivated students. It is not a substitute for basic teaching resources and libraries. But television is a modern, effective communication device. It should be used with full knowledge of its limitations--and of its many advantages.

[Reprinted from Journal of Chemical Education, vol. 33, p. 257, June 1956]

AN EXPERIMENT IN TEACHING GENERAL CHEMISTRY BY CLOSED-CIRCUIT TELEVISION Grant W. Smith, the Pennsylvania State University, University Park, Pa.

INTRODUCTION

It is well known that enrollments in colleges and universities are due to increase tremendously in the next 10 or 15 years. Knowledge that this expansion in student bodies will 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 by sight, 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 the aid of a grant from the Fund for the Advancement of Education. The lecture part of a secondsemester general chemistry course and two complete psychology courses were taught by use of closed-circuit television. As far as we know, this project represents the first in which whole courses or segments of courses have been taught by closed-circuit television on a controlled experimental basis in a full semester.

PURPOSE OF THE STUDY

The general purpose of the study may be stated in broad terms as follows: to determine the relative effectiveness of the use of closed-circuit television in the teaching of unmodified university courses as compared with conventional methods

of teaching in the classroom. Television was not to be considered as other than a means of communicating normal good teaching to groups of students. In other words, it was planned to adapt television to the course, not the course to television.

To carry out the general purpose, several studies were required:

(1) Study the feasibility of the use of moderate-cost TV equipment for instructional purposes.

(2) Determine the acceptability of this type of instructional medium to the students, the faculty, and the administrators of the institution.

(3) Determine both the limitations and the advantages of the use of closedcircuit television in instructing various types of courses.

DESIGN AND PROCEDURES IN CHEMISTRY

The experimental design in the chemistry study was planned to give as good a comparison as possible between sections taught with the use of television and those taught conventionally without television. Both the student groups and the instructional procedures were set up so that the principal variables were in the means and conditions of communication, not in course content, instructional staff, or method of presentation of materials.

To understand the experimental design, it is desirable to present here a brief description of the course under observation. The chemistry course selected for the closed-circuit television study is the second semester of one of the two principal introductory courses offered by the department of chemistry. It is a five-credit course which consists of two lectures, one recitation, and two laboratory periods of three hours each per week. The chief factors influencing the selection of this course for the study included: the large number of students involved (about 450), the uniformity of laboratory conditions and location, and an experience of several years in the course using the same textbooks.

Only the two weekly lecture periods were directly concerned with television presentation. Lecture sections normally involve groups of from 120 to 200 students in a large lecture room. New material is presented and lecture demonstrations are used frequently. The lectures are considered to be the core of the

course.

Lecture sections are split into recitation groups of about 25 each which meet once a week with senior staff instructors. New materials are not ordinarily presented in recitation; instead, review, drill on problems, short quizzing on current work, and question-answer methods are used.

The laboratory periods are devoted to work by the students on experiments related to the lecture materials. About two-thirds of the laboratory work is spent on semimicro qualitative analysis of selected metal ions. An entire lecture group meets simultaneously in the laboratory. Graduate assistants supervise about 25 students each, and a senior staff member supervises the overall group of students and assistants.

Nearly all students who take chemistry 2 take further work in advanced chemistry courses. In general, they are students in scientific and pre-professional curricula, such as chemistry, chemical engineering, pre-medicine, and the mineral sciences. Since they have just completed the first course, chemistry 1, quite complete data on their previous background in chemistry are readily available.

Since no attempt was made to use television in the laboratory or recitation groups, the possibility of finding significant differences between televised and control instruction is reduced. It must also be observed that learning may occur not only as a result of lecture demonstrations but also from the textbook, the laboratory exercises, and the recitation periods with respect to which all sections were treated alike.

The students in lecture sections were divided into three groups, one of which was taught in the originating room, while a second (divided into four subgroups) received the lecture demonstrations over the television systems in the receiving rooms. The third group, which constituted the control group, was taught in the originating classroom with no television equipment present.

Random assignment of the students to the three experimental lecture groups was impossible due to the nature of the course, so a matching procedure was used to obtain equivalent groups based on two principal factors: (1) curricular interest, and (2) grades in the preceding course in chemistry.

ASSIGNMENT OF INSTRUCTORS

The instructors who were to participate in the television project were selected on the basis of recognized competence and experience and also on their interest in such participation.

The three lecturers were men who had had previous experience in lecturing for this course.2

Their responsibilities included:

(1) The planning of the order of presentation of materials.

(2) The preparation of the individual lectures and demonstrations.

(3) Participation in planning sessions and regular weekly staff meetings.

(4) The primary responsibility for the preparation of the three monthly examinations and the final examination.

(5) Observation and reporting of reactions of students, as well as their own reactions to the course.

Each lecturer assumed full responsibility for one-third 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 to 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 to note student reactions and subjectively judge the effectiveness of the presentation.

Their responsibilities included, in addition to 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.

3

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. 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 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 life).

2 Besides the author, the lecturers were Profs. C. G. Haas and Thomas Wartik.

3 Carpenter, C. R., L. P. Greenhill, et al., "An Investigation of Closed-Circuit Television for Teaching University Courses" (Project No. 1), The Pennsylvania State University, July 31, 1955, 102 pp.

(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 to light as compared with the image orthicon camera.

These

Standard Westinghouse 24-inch table-model receivers were selected. proved to 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-inch 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-inch speaker located in the side of the cabinet did to give satisfactory sound level and quality. Accordingly, in each of these receivers the 5-inch speaker was replaced by an 8-inch speaker in a small baffle box, mounted underneath the receiver and directed toward the class.

In order to locate the receivers at a convenient height and to make them easily movable and accessible for servicing, special lightweight metal stands were designed and constructed from 1-inch angle iron. These stands had adjustable legs so that the height of the center of the screen could be adjusted between 4 feet 6 inches and 5 feet 6 inches. 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 inches over the top front of each receiver were installed.

(2) Each receiver was tilted forward by placing a 4-inch block of wood under the rear edge.

(3) The window shades were usually drawn and only part of the room lights were used.

The Dage television cameras, two in number, were located in the fourth row of seats in the chemistry lecture auditorium. From this position the full length of the blackboard and lecture demonstration table could be covered without obstruction. The cameras and operators did not obstruct the vision of the students in the lecture room. The two cameras were mounted side by side, and each was equipped with three lenses on a turret (1-, 2-, and 3-inch lenses). A 4-inch lens for ultra closeups was included in the equipment used in the fall, 1955.

With this arrangement it was possible to use one camera for long shots and the other for closeups, or to have one camera on while lenses were being changed on the other. In addition, the availability of two cameras provided a safety factor in the event of a breakdown with one camera.

Control equipment was conveniently located in a small room immediately underneath the elevated seats in the lecture room. The control equipment, consisting of two camera controls, switching unit, audio-video mixer, synchronizing generator, power supplies, and a monitor, was mounted on a simple type of console.

A small chest microphone was used by the instructor. This was an Electrovoice Lavalier type dynamic microphone of low impedance. It was inconspicuous since it could be worn under the necktie, allowed free movement, and gave a uniform level and high quality pick-up.

While a 24-inch receiver was available to the instructor to see how his demonstrations appeared on television, its use was found unnecessary and was discontinued.

As a result of early experimentation with the vidicon cameras, it was found that between 150 and 200 foot-candles of illumination were desirable for optimum quality pictures using a lens aperture of f/2.8. Original room lighting in the lecture room was only about 10 foot-candles. A lighting pattern was worked out using 7 incandescent lighting units: 3 floodlights ("scoops") and 4 spotlights. Two spotlights of 2,000 watts each were located on the side walls, in front of the instructor's table, to provide "modeling" light of fairly high contrast. Two similar units located nearer the front wall gave side and back light and lighted black

board and table. These spotlights were mounted about 14 feet above floor level. The 3 1,500-watt "scoops" were mounted on a 2-inch pipe suspended by cables from the ceiling so that they could be raised or lowered by a windlass. (See Figure 1.)

THE TECHNICAL STAFF

For any sustained experiment involving television equipment, it is necessary to have an adequately trained staff of technicians and operators. If closed-circuit television is to be feasible for economical college or university instruction, it is essential that such staff requirements be kept to a working minimum, and that personnel available on campus be used so far as possible.

Our technical staff consisted of both regular staff members and students. Members of the Instructional Film Research Program at the University are highly versed in matters of camera operation, lighting, and other skills required for filming and projection of effective teaching procedures. Student engineers, both graduate and undergraduate, were used for testing and maintaining equipment as well as in operational phases of the work. Several key men spent some time at the factories of the equipment manufacturers to receive special training. In addition, the services of consultants from the manufacturers were available and engineers from nearby television stations were brought in for technical aid on one or two occasions.

For actual operation in televising the instruction, three men were used as minimum staff. These were the two camera operators, usually students with a few hours preliminary training, and a control operator, usually a trained member of the IFRP staff. The control operator was in continual, two-way communication with the cameramen. He was responsible for seeing that a good picture and sound were relayed to the receiving rooms at all times. Camera angle, size of viewing field, and correct centering on field were items subject to his judgment and guidance. A student engineer was usually on standby duty.

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 to be ignited in midair, the cameraman had to be aware of the fact or he might leave the camera on the bubbleblower instead of the ascending bubbles. Frequently the instructor would indicate what to look at, emphasizing the important points to 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 to the demonstration table. This takes full advantage of one of television's greatest potentialities, the ability to give a closeup view. This procedure was tried out during the final chemistry lecture demonstration 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 television 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 at a disadvantage.) Slides were used from time to time and these were satisfactorily televised directly from the screen in the originating classroom.

In practice it was found that a few special modifications of instructional procedures were needed:

(1) Use of the blackboard.-It was found that for writing on the blackboard to be legible on the television screens the instructor should use only one panel (5 feet wide) at 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 television 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 to reduce excessive movement.

(3) Checking demonstrations.-When there was some doubt as to whether a demonstration would be visible on television, it was tried out ahead of time to 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.