REPORT RESUMESED 011 121 SE 002 770MODERN TEACHING AIDS FOR COLLEGE CHEMISTRY -- PORTABLE VIDEORECORDING SYSTEMS, NEW USES FOR FILMS, COMPUTER ASSISTEDINSTRUCTION.5Y- LIPPINCOTT, W.T. BRASTED, R.C.ADVISORY COUNCIL ON COLL. CHEMISTRYREPORT NUMBER ACCC- TAC -SER- PUB -18 PUB DATE DEC 66EDRS PRICE MFSO.25 HC -$2.24 54P.

DESCRIPTORS- *AUDIOVISUAL AIDS, *COLLEGE SCIENCE, *CHEMISTRY.*CONFERENCE REPORTS, *INSTRUCTION, BIBLIOGRAPHIES, COMPUTERASSISTED INSTRUCTION, EDUCATIONAL TELEVISION, FILMS,PROJECTION EQUIPMENT, TELEVISION, ADVISORY COUNCIL ON COLLEGECHEMISTRY, STANFORD UNIVERSITY

RESULTS OF A 1966 CONFERENCE ON TEACHING AIDS FORCOLLEGE CHEMISTRY ARE SUMMARIZED IN THIS REPORT. MAJORSECTIONS OF THE REPORT ARE (1) PORTABLE TELEVISION TAPERECORDING SYSTEMS, (2) FILMS AND FILM LOOPS, AND (3)COMPUTER- ASSISTED INSTRUCTION. A SUMMARY OF PRESENT ANDPOTENTIAL INSTRUCTIONAL APPLICATIONS FOR EACH MAJOR TYPE OFMEDIA IS PRESENTED. INFORMATION ABOUT THE PURCHASE, USE, ANDMAINTENANCE OF EQUIPMENT IS PROVIDED. THE SECTION ONEDUCATIONAL TELEVISION CONTAINS INFORMATION ABOUT CLOSEDCIRCUIT TELEVISION EQUIPMENT AND THE BASIC PRINCIPLES OFVIDEO TAPE RECORDING. FILM LECTURE- EXPERIMENTS, SINGLECONCEPT FILMS, FILMS THAT ILLUSTRATE THE STRUCTURE ANDOPERATION OF INSTRUMENTS, FILMS FOR OUT- OF-CLASS VIEWING,FILMS COORDINATED WITH OTHER TYPES OF MEDIA, ANCILLARYMATERIALS FOR FILMS AND TAPES, AND FILMING TECHNIQUES ARECONSIDERED IN THE SECTION ON EDUCATIONAL FILMS. THE SECTIONCONCERNING EDUCATION FILMS ALSO INCLUDES A COMPREHENSIVEGUIDE TO SOURCES OF VISUAL AIDS, A DESCRIPTION OF THEFEATURES, SOURCES, AND COSTS OF VARIOUS TYPES OF PROJECTIONEQUIPMENT, AND A DISCUSSION OF PROJECTION :SCREENS. THESECTION ON COMPUTER- ASSISTED INSTRUCTION INCLUDES A GENERALDESCRIPTION OF NECESSARY EQUIPMENT, AN EXPLANATION OF ATYPICAL PROGRAM, AND THE APPLICATION OF COMPUTER - ASSISTEDINSTRUCTION TO THE TEACHING OF CHEMISTRY. REFERENCES FOREDUCATIONAL TELEVISION AND COMPUTER- ASSISTED INSTRUCTION AREAPPENDED. THIS DOCUMENT IS ALSO AVAILABLE FROM THE ADVISORYCOUNCIL ON COLLEGE CHEMISTRY, DEPARTMENT OF CHEMISTRY,STANFORD UNIVERSITY, STANFORD, CALIFORNIA 94305. (AG)

MODERN TEACHING AIDSFOR COLLEGE CHEMISTRY

A Project Of TheTEACHING AIDS COMMITTEE

of theADVISORY COUNCIL

ON COLLEGE CHEMISTRY

au, ,

wisp,777",411,011tit ,

U.S. DEPARTMENT Of HEALTH. EDUCATION a WELFARE

OFFICE Of EDUCATION

THIS DOCUMENT HAS KEN REPRODUCED EXACTLY AS RECEIVED FROM THE

PERSON OR ORGANIZATION ORIGINATING 11 POINTS Of VIEW OR OPINIONS

STATED DO NOT NECESSARILY REPRESENT OFFICIAL OFFICE OF EDUCATION

POSITION OR POLICY

MODERN TEACHING AIDSFOR COLLEGE CHEMISTRY

PORTABLE VIDEO RECORDING SYSTEMSNEW USES FOR FILMS

COMPUTER ASSISTED INSTRUCTION

A Project Of TheTEACHING AIDS COMMITTEE

of theADVISORY COUNCIL

ON COLLEGE CHEMISTRY

Contributors: W. R. Barnard, Ohio State University; R. C. Brasted, University ofMinnesota; W. B. Cook, Advisory Council on College Chemistry; E. L. Haenisch,Wabash College; R. N. Hammer, Michigan State University; J. J. Lagowski,University of Texas; W. T. Lippincott, Ohio State University; W. T. Mooney, ElCamino College; B. E. Norcross, State College, N. Y. at Binghamton; W. H.Slabaugh, Oregon State University; J. A. Young, King's College.

SERIAL PUBLICATION NUMBER 18 DECEMBER 1966

ADVISORY COUNCIL on COLLEGE CHEMISTRYDepartment of Chemistry, Stanford University, Stanford, California 94305

The Advisory Council on College Chemistry is an independent group of chemists interestedin how improvement and innovation in undergraduate chemistry curricula and instruction canbe effectively implemented at the national level. The Council collects and disseninates informa-tion through the activities of standing committees on Freshman Chemistry, Curricula andAdvanced Courses, Teaching Aids, Teacher Development, Science for Non-Science Majors,Junior Colleges, Resource Papers, and an Editorial Committee. Additional ad hoc groups act asnecessary. The Council hopes to provide leadership and stimulus for imaginative projects on thepart of individual chemists.

The Council is one of a group of collegiate commissions supported by grants from theNational Science Foundation. The Council cooperates in intercommission activities.

OFFICERS and STAFFL. C. King, Chairman; W. H. Eberhardt,Vice-Chairman; W. B. Cook, Executive Direc-tor; A. F. Isbell, Senior Stag Associate.COUNCIL MEMBERS: Bobbin C. Ander-son '87, The University of Texas; Cordon M.Barrow, '68, Case Institute of Technology;0. Theodore Benfey, 68, Earlham College;Henry A. Bent, '69, University of Minnesota;Robert C. Brasted, '69, University of Min-nesota; Melvin Calvin, '67, University of Cali-fornia; J. Arthur Campbell, '68, Harvey MuddCollege; William H. Eberhardt, '68, GeorgiaInstitute of Technology; Harry B. Cray, '69,California Institute of Technology; EdwardL. Haenisch, '67, Wabash College; David N.Hume, '69, Massachusetts Institute of Tech-nology; Emil T. Kaiser, '09, The University ofChicago; Michael Kasha, '69, Florida StateExiscutive COMMitiel.

II

University; William F. Kieffer, '67, The Col-lege of Wooster; L. Carroll King, '69, North-western University; Richard J. Kokes, '67,The Johns Hopkins University; Elwin M. Lar-sen, '68, University of Wisconsin; 'W W. T. Lip-pincott, '67, The Ohio State University; How-ard V. Malmstadt, '89, University of Illinois;William T. Mooney, Jr., '69, El Camino Col-lege; Leonard K. Nash, '87, Harvard Univer-sity; Melvin S. Newman, '68, The Ohio StateUniversity; Charles C. Price, '69, Universityof Pennsylvania; Charles N. Reilley, '68, Uni-versity of North Carolina; Frederich W.Schmitz, '67, New York City Community Col-lege; Glenn T. Seaborg, '67, Atomic EnergyCommission; Robert I. Walter, '69, HaverfordCollege; Peter E. Yankwich, '88, University ofIllinois; Jay A. Young, '68, Kings College.

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0

PREFACE

This report is the result of a writing confer-ence held at Stanford University in late July andearly August of 1966. It was conceived at a con-ference on new teaching aids sponsored by theAdvisory Council and held at the MIT ScienceTeaching Center in March 1966. At that time, itbecame apparent that very recent technologicaldevelopments in the audio-visuals industry hadmade available relatively inexpensive, especiallyreliable, and uncommonly easy to operate filmprojectors, portable video tape recorders andother hardware, all of which appeared to offerunusual potential for improving college chem-istry instruction. Because most participants atthe MIT conference were unfamiliar with thenew hardware and its potential, it was suggestedthat a rather detailed summary of these new de-velopments and of their applications to chemis-try instruction be prepared and made availableto college chemistry teachers.

Mr. Robert Barnard, then at Montana StateUniversity and nova at Ohio State University,assumed the heavy burden of gathering infor-mation on films, film hardware, and on videotape systems. He, in collaboration with ProfessorE. L. Haenisch, W. H. Slabaugh and W. TMooney, is largely responsible for the section ofthe report on films. Professors W. B. Cook, R. N.Hammers W. T. Lippincott, and B. E. Norcrossassembled and wrote the section on video sys-tems. Professors J. J. Lagowski, and J. A. Youngcontributed the section on computer-assisted in-struction. Professors W. T. Lippincott and R. C.Brasted read and edited the entire report.

The members of the writing team are in-debted to the consultants, Mr. John Flory ofEastman-Kodak, Mr. Don Horstkorta of the

SONY Corporation, Mr. David Thowas ofReeves Engineering and Mr. William Justus ofthe Telecommunications Center at Ohio StateUniversity, for their, invaluable advice duringand after the writing conference. Acknowledge-ment also is made to Mrs. William B. Cook andher staff at AC3 headquarters aid to Mrs. SueAdler of Ohio State University for eir consid-erable assistance in the prepar ition of the manu-script. Photographs of television monitors weremade by Mr. Dave Eelby of the Teaching AidsLaboratory at Ohio State University.

The Teaching Aids Committee will continuein its efforts to develop materials to exploit thecapabilities of new audio-visual techniques.Every effort will be made to bring these newcapabilities before the chemical education com-munity and, when possible, to distribute samplesof the developed materials to interested collegechemistry teachers. We also are interested inlearning of activities or programs which employnew teaching aids or techniques so we fan fa-cilitate the spread of novel ideas and applica-tions. In addition, we encourage inquiries onthese matters and will appreciate assistance onour several projects designed to improve collegechemistry instruction by the effective use ofaudio-visual aids.

The Teaching Aids Committee of AC,J. A. CAMPBELL

W. B. CooxE. L. HAENISCH

W. F. KIEFFER

H. V. MALMSTADT

J. A. YOUNG

W. T. LIPPThicorr, Chairman

101

Growing zinc dendriteswith accompanying animated growt

sequence. Photographed from color film, "Metal Crystal

in Action" produced by American Soci'ety for Metals.

ofh.*Piaan,

TABLE OF CONTENTSINTRODUCTION . . . . . . .

Portable Video Tape Recording Systems .

TV in Chemistry Instruction . .

New Capabilities and New Uses .

Preparation of Video Tapes . . .

Closed Circuit Television Systems . .

.

.

. 1

5

5

5

7

7

The basic video recording installation . 9

Expansion of the basic video recording installation 9Distribution of television signals . . . 11

Lighting . . . . 11

Maintenance 11

Video tape . . . . . . 11

Large screen television projection . . 12

Color television . . . . . 12

Principles of Video Tape Recording . . . . . . . . 13

Role of TV Cameras and Accessories . . 13

Video Tape Recording . . . . . 13

Video recorder heads . . . . 14

Rotating recorder heads . . 14

Image sharpness in video recordings . . 14

Editing, Interchangeability and Standards . . . 15

Films and Film Loops . . . . 17

New Uses for Films . . . . 17

Some specific examples . . . . . 19Auxiliary materials for films and tapes . . 23

Sources of Chemistry Films . . . . 24Film directories . . . 24Other film sources . . . . . 25

Equipment: Its Availability and Uses . 26Film types . . . . . 26Projectors . . . . . 27Sound characteristics of film . . . 29Film costs . . . . . 31

Cameras and lenses . . . . . . . 31

Still projection systems . . 31

Utilization of Projected Materials . . . . 32Projection screens . . . 32

ComputerAssisted Instruction . . 37

Equipmeat . . . . 37

Programs. . . . . . . . 38

The Use of ComputerAssisted Instruction in Chemistry . 41

Laboratory . . . 0 41

Tutorial assistance . . . . 42Evaluation of student ability and progress . . 42Incorporation of other material . . . 42

Summary. . . . . . . . . . . . . 43

References and Footnotes . . . . . . . 45

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INTRODUCTIONThe knowledge explosion, which for chemis-

try at this writing brings a doubling of the totalamount of published chemical information everyseven and a half years, and which provides acontinuous, exciting and enriching challenge forchemistry teachers who remain intrigued withtheir subject, has created the conditions for amajor breakthrough in the art and science ofteaching.

Last year a Nobel Laureate sitting in his of-fice in California lectured to a class of chemistrystudents in Montana. As he wrote and drewformulas on a pad in front of him, the studentsread his words from a projection screen at thefront of their classroom. When a student had aquestion, he pressed a button and the professor,receiving the signal, immediately acknowledgedit, listened to the question and responded. Boththe students and the professor were thrilled bythe experience. Needless to say the teaching-learning interaction proceeded with unusualefficiency.

Earlier this year an engineer demonstratingnewly developed television tape equipment ob-tained permission to tape a chemistry class insession. During the lecture the instructor igniteda balloon containing hydrogen. After class somestudents asked to see a replay of that portion ofthe tape. The engineer while slowing down themotion suddenly stopped it on one frame andthere, in perhaps the first stop-action from tapereplay in a chemistry classroom, was the imageof the balloon one side a bursting mass offlames, the other side still intact.

A chemist at Bell Telephone Laboratories,teaching other chemists some uses of computers,shows how the instrument can be programmedto reproduce the nuclear magnetic resonancespectra of some cycloalkanes. He notes, how-ever, that the spectrum of one strained com-pound does not correspond to the computer-generated spectrum. Suspecting that perhapsthe HCH bond angle is incread in this sub-stance, he asks the computer to give him thenmr spectrum for this compound if, while allother parameters remain constant, a slightchange is made in the bond angle. The compu-

.11111

ter responds in seconds with a new spectrumwhich is a close fit but not an exact fit. Againthe chemist increases the bond angle in the com-puter program and requests still another spec-trum. This time the fit is even closer.

Without arguing the pros and cons of whetherchanges in parameters other than the bond anglemight give a similar fit for the computer gener-ated nmr spectrum, the profound message here isthat the classroom teacher now has available tohim computing capability having incrediblememory and able to display its results in numeri-cal or in graphical form or even as a movingimage.

It is mechanical developments such as theBlackboard-by-Wire, the Data Phone with VoiceWriter, the portable television tape recorder, thecartridge-loading movie projector, the shared-time computer with terminals located in class-room which have created the conditions forrevolutionary innovation in teaching and learn-ing processes. The examples cited above are butthree of many that could be given.

Within six months, and at a cost to his institu-tion of not much more than his own yearly sal-ary, a chemistry instructor could have at hisdisposal:

The capability to insert into his lecture withthe push of a button a 30 second or longersegment of film which illustrates preciselythe point under discussion, in color, in mo-tion, and accentuated by pertinent filmedtechniques such as close up, time lapse,slow motion, or animation. Such film seg-ments could be reversed, re-run, and anynumber could be shown in a lecture allof this via push button control in the handof the lecturer.The opportunity to prepare, perhaps onlyhours before use, a television tape of an ex-periment which students could never seeotherwise. By replaying the tape, the classcould not only see the experiment as it wasperformed, but they could make observa-tions, collect data from their seats, and, asa group, discuss the results and arrive atconclusions. As with films, the techniques

1

4111

such as magnification, slow-motion, time-lapse photography would be readily avail-able and could be easily used by the in-structor as he and perhaps a student assist-ant prepare the tape.A library of single concept film loops pack-aged in cartridges and ready for immediateviewing simply by inserting the cartridgeinto a suitable projector. This library of filmloops might be located in the instructor'soffice or in the library. Students having dif-ficulty with a concept can be handed theappropriate cartridge and asked to viewthe film as often as they wish. Such viewing

can be done in a study carrel or in a small

quiet area. Home assignments of materialwhere motion, color, or time is importantcan be filmed and students can borrow thefilm cartridges as they borrow books onreserve.A library of film loops on laboratory tech-niques for use in inexpensive projectorslocated in the laboratory. Similar filmsshowing the operation of instruments canbe placed in projectors and located besidethe respective instruments. The resultswould be a saving of faculty time on rou-tine laboratory matters.A lecture table, digital voltmeter with aread-out like a small basketball score board.This would be equipped with probes whichwould enable the instructor to measure ex-

perimental parameters such as temperature,voltage, pH, conductivity, vapor pressure.Lecture experiments, as for example theeffect of concentration on the voltage of agalvanic cell, could be performed by the in-

structor with students collecting and work-ing up data at their seats.

Each of these capabilities already is in opera-tion in colleges. Nearly all are being used in

chemistry classrooms. Films, for the uses indi-cated, now are available and more are beingdeveloped. The hardware, in most cases, is

readily available at moderate costs and is re-markably easy to use and to maintain. Whileinstructors will find it takes time to producequality materials with this new equipment,those who have tried agree that the work is far

2

more rewarding, much more foolproof, andmuch less time consuming than were efforts withequipment commonly available in the past.

It is for those who would use these new tech-niques and who would explore some of the al-most unlimited number of teaching innovationsthey make possible that this report has beenprepared. Its content is limited to three areas inwhich recent technological developments havecreated unusual new potential for college chem-istry instruction. These areas are:

Portable TV tape recording systems.Films and film loops.Computer-assisted instruction.

The first section of each part of the report isa summary of present and potential instructionalapplications in the light of the new technologi-

cal capabilities. The second section gives infer-mation regarding equipment, how to use it,where to buy it and, when possible, how tomaintain it. In the second section, no effort hasbeen made to list all manufacturers and all items

of equipment. Materials listed are, in general,those with which some member of the writingteam has had experience. The primary aim inthis section is to inform chemistry teachers ofthe new equipment available and to providethem with sufficient background information tomake an intelligent judgment about the pur-chase and use of such equipment.TV systems. The first section of Part I on TVtape recording systems is largely a summary of

the experiences of those who have used TV inchemistry instruction. It includes the findings ofthe Teaching Aids Committee television tapeproject conducted during the spring and sum-mer of 1966. In this project, portable TV tapesystems were sent to the chemistry departmentsat five colleges and universities ( Michigan StateUniversity, Montana State University, OhioState University, Stanford University and Wa-bash College) where staff members made tapesof various chemically interesting phenomenaand equipment. An evaluation of the tapes pro-duced was made by several members of theTeaching Aids Committee in August of 1966.

The hardware section of Part I was preparedby a writing team of chemists with assistanceand advice from television engineers and pro-

L

ducers from the industry and from the univer-sities as acl,nowledged in the Preface. The writ-ing team has made every effort to give an accu-rate but elementary presentation of the princi-ples of TV tape recording. Unfortunately, thefield of portable TV tape recording is so newthat consensus among the experts often is dif-ficult to obtain. Therefore, it became necessaryto choose among alternatives on certain pointsin this section. Hopefully, these choices will notprove an inconvenience.

Also included in this section is a listing of theitems needed in a basic TV recording installa-tion and suggestions for expanding the TV capa-bility.Films. The first section on films summarizessome new uses of films and film loops and in-cludes the results of several film preparation pro-grams sponsored or stimulated by the TeachingAids Committee. During the spring and summerof 1966, approximately 15 film loops illustratingvarious applications at all undergraduate levelswere prepared. Some of these are original films,others were made by extracting footage from ex-isting films. The film preparation programs arecontinuing to produce sample loops which willbe available on request.

Also included in this section are lists of filmsources and sources of film reviews.

In the hardware section, an effort has beenmade to bring together the principles of movieprojection. Included are subsections on film for-mats, on projectors and their characteristics, onlenses, sound, screens, and on some new devel-opments in still-projection techniques. This sec-tion should serve as a handy guide when pur-chasing equipment and when setting it up so as toobtain the best results.Computer-assisted instruction. Chemists arejust' starting to experiment with this new tool.Hence, the experience here is sparse, and thetreatment is elementary. Diagrams are givenillustrating the principal of shared time com-puter use in instruction. A sample of student-computer dialogue is included to indicate thekind of interaction that is possible here. Whilethis sample includes especially elementarychemistry to make the point in limited space,actual computer lessons could be on topics con-

111

siderably more complex. Such lessons wouldforce the student to think his way through theproblem presented, often allowing him altera-tive routes to solutions or permitting him tomove some distance along a non-productivepath before bringing him back to a potentiallyproductive one.

While computers undoubtedly will be used ininstruction in numerous other ways, our experi-ence at present is insufficient to report intelli-gently on these. Nevertheless, projects to ex-plore the uses of computers as in class aids( c. f. Bell Telephone example given earlier )and to prepare some computer-animated filmsare underway and, hopefully, will be the sub-ject of a subsequent report.

Teachers may well ask if they must becomeaudio-visual aids experts and thereby dilute theirsubject matter competence. Those who havetried these new techniques believe that they notonly enhance the efficiency of presentation butthey also enrich the learning process, therebyincreasing the quality of instruction.

The top priority problem in chemical educa-tion today is to discover how to develop chem-ists who have in their minds a much larger bodyof chemical knowledge and greater facility in itsuse than chemists have had in the past. Withoutthis the research of the future will be severelylimited. For this reason, all avenues which willspeed up the learning process should be ex-plored thoroughly. Hopefully, the efforts stimu-lated by new developments in audio-visual hard-ware will be a start in this exploration.

Members of the writing team had an oppor-tunity to visit an elementary school where com-puters were used in an experimental project toteach reading to first grade students and arith-metic to fourth grade students. The staff hadnot evaluated the effectiveness of the project butthey stated that although the youngsters seemedto enjoy working briefly with the computer theywould do anything possible to get personal atten-tion. If this understandably human trait carriesover into the college age group, it suggests thatthe best learning experience will continue to becentered around a live teacher, but assisted bythe best that technology and a film maker's artcan provide.

3

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°

TV close-up of an emerging infrared spectrum

PORTABLE VIDEO TAPE

TV IN CHEMISTRY INSTRUCTION

Television has been used in college chemistrycourses in numerous ways, most often in generalchemistry.' For example, chemistry departmentsin several schools including the University ofMinnesota and Purdue University have used itfor pre-laboratory discussions and to illustratespecific laboratory techniques. At the Universityof Texas and at Oregon State University the lec-ture and laboratory portions of general chemistrycourses have been put on kinescope film.The kinescopes have been used repeatedly atthe originating institution and they have beentelecast to neighboring colleges. At the Univer-sity of Florida general chemistry lectures weretaped and shown to many small groups of stu-dents thus eliminating some of the large sec-tions. At Montana State University and at Rens-selaer Polytechnic Institute live and taped TVhave been used as a lecture demonstration aid.

Various techniques were used by the instruc-tors responsible for developing these televisionpresentations. For example, at Oregon Statekinescopes of the lectures and laboratory ex-periments were prepared and these were pro-jected on large screens. At most schools thetaped or live presentations were shown to stu-dents on TV monitors located in classrooms orin laboratories. Classrooms of all sizes suitablefor groups of from 20 to 500 students have beenequipped with monitors and used successfullyfor TV presentations.

A television camera located on the lecturetable and used to magnify demonstrations, totransmit and enlarge a photograph or diagram,or to convey the instructor's written words havebeen used at Rensselaer and at Montana State.

In general, attempts to replace the live lec-turer by an instructor appearing on a televisionmonitor have not persisted; however several ofthe other applications, such as the teaching oflaboratory techniques, magnification of lectureexperiments and demonstrations using both live

RECORDING SYSTEMS

television and tape in the classroom continue tobe used.

New Capabilities and New uses Perhaps thegreatest potential for television in increasing thequality of chemistry instruction lies in the utili-zation of the recently developed, relatively in-expensive and rugged portable television taperecorders. These recorders make it possible foreven small chemistry departments to own aclosed-circuit television system a camera, a TVtape recorder and monitors or a projector. Withthis equipment instructors can utilize live TVin their classrooms or they can make their owntapes with a minimum of effort.

Video tape can record anything that can beseen. It can do so simply and economically onmagnetic tape that can be erased for re-usewhen the recorded information is no longer use-ful. Portable recorders, only twice the size of astandard office typewriter, are priced from oneto four thousand dollars and can be used easilyand dependably in the laboratory or classroom byinstructors or student-assistants. Immediateplayback on any number of television screens isas simple as the playback of audio tape.

Video tape can bring into the classroom, in-struments and apparatus that students wouldnever see otherwise. For example, the operationof the mass spectrometer, and the details of theelector microscope or the sample chamber of aspectrophotometer now can become available toall students. Tapes can be prepared so that stu-dents can take readings from the dials or from thecharts of the instruments being used in the ex-periment. In addition, unique or hard to arrangeevents can be recorded for repeated viewing.Video tape recording also stores and repeats ma-terial of temporary interest whether it be in-structions to the multiple sections of a teachinglaboratory or a record of a new teaching assis-tant's conduct of a class which he can later viewand criticize.

The video tape recorder serves well as an*We are grateful to the following for supplying summaries of their experiences with television teaching for this report: Professor J. F. Baxter,University of Florida; Professor R. C. Brasted, University of Minnesota; Professor R. L. Livingston, Purdue University; Professor L. 0. Morgan,University of Texas; Professor R. O'Connor, Kent State University (experience at Montana State); Professor H. Richtol, Rensselaer PolytechnicInstitute; Professor W. H. Slabaugh, Oregon State University.

5

IIMMIIIIM111/

erasable slate on which to try, test and immedi-ately criticize visual aids to understandingchemical principles and practices. It is a me-dium for impromptu creativity. On the spur ofthe moment, an instructor can record an illus-

tration for his lecture. After using it, he candecide whether the recording should be saved,altered or erased and forgotten. In general,video tape recording should be used when itcan provide learning situations not availableotherwise.

During the summer of 1966, television taperecorders and cameras were sent to chemists atseveral colleges and universities. These teacherswere asked to test the equipment and to pre-

pare tapes of experiments, demonstrations, mod-els, or other instructional features which theyfelt could be shown more effectively by thismedium than by conventional methods of pre-sentation. Without exception, all of these teach-ers were impressed with the potential of thismedium and with the ruggedness and ease ofoperation of the equipment. Table TV-1 is asummary of the kinds of tapes prepared in thisproject.

In addition to these tapes, a variety of otherapplications made possible by chemistry depart-ment-owned-and-operated video systems havebeen tried or suggested. Some of these are listedin Tables TV-2 and TV-3.

TABLE TV-1

.

Examples of Tapes Prepared by Chemists Using Portable Video RecordersA.1...

Topic............................p.iiSpectrophotometer

MR Spectromater.

X-ray Power Analysis

McLeod Gauge

Vapor- Liquid Chromatography,

f.i. Crystallization .;,..

Reading Burets -

ing Charts

-

Description of Tape Prepared.

,

Preparation of sample; loading and operating spectrophoto-

meter; interior operation of instrument.

Preparation of sample; loading fii-id operation of instrument

Preparation of sample; loading x-ray camara;:*iii urline separations.

, .,

Operation and reading of instrument.

Preparation of sample; operation and reading of instrume

,..f% Recorded directly; camera mounted on tnit , 0

Meniscus spread across TV screen.,...z

Charts and oscilloscope screen spread across IVreading can be made from monitor.

Ion of valcuMW, In',.,

... ,, ,

TABLE TV-2

Ses of TV Tapes in Chemistry Laboratory Instruction

taborilbsy Examinationse,

4:01.1`Meters

roPhotorn

vy

Crystallization

itration

,Quantitative transferA

plete experiments

rx rid post-lab sessiOns

nirparies Octets from g

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TABLE TV-3

Close-up of a buret as seen on a video monitor

Preparation of Video Tapes In many educa-tional situations it is desirable to present pic-torially a concept, technique or process in aninformal manner. For instance, a brief illustra-tion of an extraction with a separatory funnelcompared to the operation of a counter-currentdistribution apparatus could easily be recordedin the afternoon or evening for a presentationthe next day. Such taping could be done by thefaculty member with the assistance of a teach-Mg assistant. In general, while the faculty mem-ber needs to have access to the expertise of anaudio-visual man or department, the productionof a video tape should be and easily can beunder the sole direction of the subject expert,the faculty member.

In preparing such a tape sequence, the in-structor ordinarily would arrange the materialsand then rehearse what he plans to do with thecamera turned on and with the output madedirectly into the monitor. In this way, he or theassistant can see each operation as it will event-ually appear on tape. Even after rehearsals andrecording on the tape, if a particular sequence isunsatisfactory, it is very simple to erase the tapeand re-record the section.

All of these capabilities need to be exploredand exploited in college chemistry. To do so re-quires some familiarity with the underlyingprinciples, nomenclature and equipment of tele-vision tape recording. Following is a brief dis-cussion of the equipment needed for video re-cording including sources and costs. This willbe followed by a brief discussion of some princi-ples of video tape recording.

CLOSED CIRCUIT TELEVISION SYSTEMS

The essential components needed in a basicsystem for live video recording are indicatedin Figure TV-I. Although the first portable videotape recorders required an engineer in attend-ance, now any of the professional or near pro-fessional staff associated with a chemistry de-partment can learn to operate one in a fewminutes. Probably the biggest change in the lastyear, however, is the advent of really good re-corders priced under $5000. Examples of theseand slightly more expensive recorders are givenin Table TV-4. With a camera and all necessaryaccessories, the total price for a modest but thor-oughly useful beginning television recordinginstallation is under $7500.

7

E.*

An AMPEX video tape recorder

TABLE TV-4

FIGURE TV-1Elements of a video recording system

Representative Portable Television Tape Reawders

AmpexWO

SonyPV120

Ampex7000

Sonytv-200

ConcordVIR400

Whom*150

,Tape Size 2" 2" 1.. 1" SP .i PO

Max. PlayingTime/1 reel 4 hr. 90 min. 1 hr. 1 hr. 1' .

Tape.

:Sound Capabil-ity, (Channels.)`Remote Controls'Useful for corn.Cleteete remote

2 1 Churr

No

Char I C,

,

I Ch au;

,

,

tpien. ,

operation.!Tose of Opera-

,

Von:Rapid Fd'wd. Yes Yes No Yes No Yes

`» Rapid Reverse. Yes Yes Yes Yes Yes Yes

,Stop Motion. Fair Good Fair Good Fair Fair

Allow Motion No Good No Good No No

Output Video Video Video Vide' Video w Video

esolution*center lines,orizontal)

,

320

R.F.

350 320

R.F.,

250

R.F.

l NotAvailable r.

Pe SPeed.Inches/sec. 3.7 4.5 9.6 7.8 12 7.5 7.6

,'eight 00 lb. 150 lb. 100 lb. 88 lb. 52 lb. 45 lb. 50 lb.

Cost of 1r. tape $70.00 $75.00 x$59.50 $69.00 $59,50 $39.95 $39.95

Recorder Price $8000. $8950. $3150. $4200. $1150. $1250. $149

*Picture quality is affected by signal-tnoise ratios and other factors in the chain of equipment from camera to monitor. Resolution of the

recorder should not be taken as the sole factor for determining good definition in the reproduced television picture.

8

The basic video recording installation. The fol-lowing basic components are needed in anyinitial installation:

One camera with internal 2:1 synchro-nizing generator such as GeneralElectric TE-20A $1595.00

One zoom lens such as Angenieux 25-100 mm f 2.8 with close-up attach-ment and extension tubes 450.00

One tripod, head and dolly such asQuick-Set Samson tripod (7301),head (7201) and dolly (7601) . . . . 148.00

One camera monitor-receiver such asthe 5-inch Sony PVJ-305 RU 260.00

One omni-directional dynamic microphone such as Sony F-91 90.00

One one-inch video tape recorder withslow and stop motion capability suchas Sony EV-200 4200.00

One 23-inch viewing monitor such asConrac model CVA23 400.00

Total $7143.00

Where the full horizontal resolution capabili-ties of the camera are to be reproduced andmaximum reliability is required, a Conrac in-dustrial type monitor should be used. If a mod-

)

erate compromise in quality is necessary forreasons of economy, the Setchell-Carlson model2100 would be a good choice. Television projec-tors which project the video image on largescreens are available and have been successfullydemonstrated. Table TV-5 lists some TV moni-tors and projectors, their characteristics andcosts.

As a practical consideration, it is important touse unmodified industry-standard componentsand connectors in assembling the basic installa-tion to permit ready introduction of additionalequipment.

Expansion of the basic video recording installa-tion The first component likely to be added tothe basic video system is a second camera to per-mit rapid switches from close-ups to wide-angleviews. Table TV-6 gives some representative TVcameras, their characteristics and costs. In addi-tion to the cost of the camera, some switchingsystem and a slight alteration in the camera syncsystem is necessary. The swi cching system maybe a simple switch costing less than $75.00 ( Pack-ard-Bell VS -3) or a dissolving device which pro-vides the capability of a continuous blend fromone camera to another. The General ElectricTC-59A switcher-fader costing $700 will do anadequate job for simple systems.

TABLE TV-5

Representative Television Monitors and Projectors

MONITORS

Sotcliall CarlsonModr1 2100

9

4'0

'!ft:1,,"

TABLE TV-6

When two cameras are available, it is alsopossible to use a special effects generator suchas Ball Brothers Mark VI-A ( about $1,375 plus$50 camera modification ). Video informationsuch as captions or numerical data can be super-imposed by means of the special effects genera-tor over the primary video image ("matting"),or such information as close-ups of instrumentparts and diagrams can be inserted onto a se-lected portion of the screen ( split screen tech-nique) .

Additional lenses for the camera may event-ually be desired. If funds are available, the basiccamera might well be equipped initially with a10:1 rather than a 4:1 zoom lens such as theAngenieux 15-150 mm f 2.8 for $790. A turretcarrying a zoom lens and a one-inch fixed focallength lens for high definition close-up work isa logical step beyond a single lens. Fixed focal

10

length lenses are generally sharper than zoomlenses. A turret with several fixed focal lengthlenses costs as much as a first class zoom lensalthough not affording the zoom capability.Angenieux zoom lenses are considered to be ofexcellent quality. Regardless of the lenseschosen, a set of standard C mount lens exten-sion tubes ( $19.50) is handy for close-up workin the laboratory and any supplementary close-up attachments supplied by the manufacturerfor a particular lens are generally worthwhileaccessories.

While TV cameras will accept any standard16 mm C Mount lens, many of these lenses aredesigned for photographic cameras and arenot suitable for television cameras. Lenses witha maximum opening of f/1.9 or f/1.4 and havingworking distance no longer than 24" and as shortas 18" probably will be most useful for the workdescribed here.

A basic camera can be equipped as follows:Turret mount

Three lens turret, $196.50

Lens, 1" f/1.5 85.00

Lens, 2" f/1.8 122.00

Lens, 6" f/2.8 119.00

Extension tubes for extreme close-upwork 20.00

$542.50Turret mount

Three lens turret, $196.50

Lens, 1" f/1.5 85.00

Lens, Zoom f/2.84-1 (17 mm-70 mm) 400.00

Extension tubes 20.00

$701.50Single lens mount

Lens, Zoom f/2.810-1 (15 mm-150 mm) $790.00

Close-up rings 40.00

$830.00

Camera supports . . A number of excellent cam-era supports are available from "Quick-Set",Inc., Skokie, Illinois. In addition to the tripodsand pan head recommended in the "starter set",an elevating camera support is available whichcan be built into the lecture demonstrationbench. This type of support can be used in twoways: One, to insure that the instructor willhave a convenient solid support on the lecturebench if he wants to use a live camera in class;and, two, on a cart designed to hold the TV taperecorder, camera and monitor. The cart and itscontents is a complete closed circuit TV systemand can be wheeled into laboratories to makerecordings or into classrooms or teaching labora-tories to display a taped or live video sequence.Distribution of television signals Use of morethan one viewing screen requires knowledge ofthe best method of connection. Whenever therecorder video output can be sent from onemonitor to another in one continuous chain, itis only necessary to tie them together in seriesfashion with a cable for video and one for audio.Installations with as many as ten monitors are

common. A distribution amplifier is needed onlywhen very long cables are required ( as from onebuilding to another) or when parallel rather thanseries connections are required in a branchingdistribution to different rooms or buildings.

If many outlets are needed over a large area,it is possible that conversion to an RF signalmight be justified. In the latter case, several in-dependent signals can be transmitted over thesame coaxial cables, or transmission can bebroadcast over the 2500 megacycle channel al-located to educational institutions. Nevertheless,it is significant that experienced television usersconsider high resolution to be the most import-ant quality required for scientific purposes. Thebest RF system will not transmit pictures assharp as a video-audio cable system.Lighting Usable video pictures can be madewith standard equipment in light levels too lowfor comfortable reading. Consequently, existingroom light often is perfectly satisfactory. If addi-tional lighting is required, simple lamps ordin-arily are sufficient. Chemists should know thathigh intensity light such as burning magnesium

can destroy a vidicon camera tube.Maintenance Television recorder heads re-quire regular maintenance not unlike that re-quired for instruments used constantly by chem-ists. The SONY and AMPEX recorders used inthese studies are remarkably rugged and requirelittle service as new instruments. This equipmenthas been shipped around the country by plane,rail, bus and car. It rarely has failed to operate.However, the recorders are largely transistorizedand complex. Moreover, their recording andvideo heads have lifetimes of 500 hours or moreand must be changed periodically. For thesereasons, recorders must be repaired by especi-ally trained technicians. Manufacturers willtrain appropriate personnel to maintain and re-pair their equipment. Regional service facilitiesare available for SONY and AMPEX. Manydealers offer service contracts.Video Tape The life of a video tape is limited.Depending on the manufacturer of the tape,and recorder, it has been estimated that from100-1000 "passes" can be expected during nor-mal tape usage. A pass is defined as any time thevideo tape goes past the recorder heads, e. g., to

11

111101,

record and play back one scene would involvetwo passes of the tape. Fast forward and re-windmodes are not considered a pass, as the tapetension is released and the tape is thus not inpressure with the recorder heads. In commonusage, the term play and pass are considered tobe equivalent.

-""111111,

A SONY video tape recorder

Large Screen Television Projection The designof many chemistry classrooms is not convenientfor the placement of TV viewing monitors. Ifthe students are expected to take data from thetelevision picture, optimum locations for eachviewer should be considered.

In general, students should sit no further than20 feet from a 23" TV monitor. Excellent recom-mendations for monitor placement are availablein Design for Educational TV by EducationalFacilities Laboratory, New York, N. Y., 1960.

By contrast, one large-screen TV projector canaccommodate the entire class with a simplifiedinstallation. Projectors are available which pro-ject a TV image up to 20 feet wide ( see discus-sion of optimum image size in film section) .Most currently available TV projectors arelimited in that their light output is so low thata semi-dark or a completely dark classroom isnecessary. Also the lenses available on manymodels require the projector to be placed in aclose relationship to the screen. This could betroublesome in the traditionally designed chem-istry auditorium. The cost for the larger TV pro-jectors is quite high. An installation of a largescreen TV projector is now being made in a350 seat capacity chemistry auditorium at OhioState University. Plans are to use the projector,

12

video tape recorders, and a lecture bench cam-era in the general chemistry lectures.Color Television Although color televisionwould be desirable, and in some cases necessaryto the chemist considering the use of this me-dium, it will be some time before color TV willbe suitable for chemistry's exacting require-ments. At present, color television cameras sellfor $60,000 to $70,000, and color video monitorsare priced from $2,500 up. In addition, the pic-ture resolution is lower than that of a compar-able monochrome picture. Color standards alsoare hard to maintain over existing distributionsystems. Chlorine gas, for example, can easily begreen, blue, or shades between, depending uponhow the receiver is adjusted.

Industrial sources indicate that it may be atleast three years before a significant change ismade in color television cameras and monitors.Even with major changes promised, the price ofcolor equipment possible will be no less thanone-half the cost of color today.

Color television using an unconventional prin-ciple has been demonstrated by Japanese manu-facturers. However, it is not compatible withAmerican standards. Although considerablylower in price, its potential and availability inthis country will not be known until late 1967.

Manufacturers of most portable recorders areprepared to add color capability by next year.The cost for adding this feature according to onemanufacturer will be close to the present sell-ing price of the one inch recorder.

Front view of a TV camera showing several lenses mountedon a turret.

3

PRINCIPLES OF VIDEO

Role of television cameras and accessories Thefirst step in a television system is to generate anelectrical equivalent of the scene. By means ofa lens the subject is brought into focus on aphotoconductive surface in the pickup tube ofthe camera and the resulting image is scannedby an electron beam. The amount of light thebeam encounters at any instant determines themagnitude of the camera tube current and hencethe video signal from the camera. Sinc.?, thevideo signal ultimately modulates the intensityof an electron beam which scans across the faceof the television viewing screen, it is necessarythat the camera tube and viewing screen scan-ning be synchronized. A synchronizing genera-tor built into the camera or elsewhere in the sys-tem generates electrical pulses which lock to-gether the scanning beams in the camera andmonitor.

The light sensitive tube used in cameras underconsideration here is called a vidicon tube. Itis highly sensitive, sturdy, and costs abot t$170.00. Image-orthicon tubes used in commer-cial television are expensive, bulky and delicate.They need not be considered for the applica-tions discussed here.

The electron beam of a vidicon tube sweepsacross the light sensitive surface from left toright so as to divide the image into 525 horizon-tal segments called lines. Each line segment ofthe video signal is ultimately reassembled in themonitor where the scanning beam starts at thetop left of the image and sweeps to the rightand down at a uniform rate (figure TV-2). Atthe end of each sweep line, the beam returnsrapidly to the beginning of the next line in itsfield. During this retrace period, no video signalexists.

An interlaced scanning system is used to re-duce flicker. The scanning beam skips everyother line down the screen, then returns to thetop to scan the alternate lines interlaced be-tween the first set. Each set of horizontal linesis called a field, and the two combined sets arecalled a frame. Since each field contains 262I/2lines, the beginning of the second field is dis-

TAPE RECORDING

first field second field

Mt 4110 ONE. MEM 41116 111.

.11.1ND OM OM .11.1ND

MM.

011111 =1 MEM

OM OM IMO MIN .11=1 4110

- - -:'="110

FIGURE TV-2Interlaced scanning principal

placed horizontally half a line. The ecmpleteframe therefore contains 525 scanning lines.Scanning speed is such as to generate the tele-vision picture at the rate of thirty frames asecond.Video tape recording Video tape recording ispresently accomplished by methods quite simi-lar to magnetic sound recording. The essentialparts of a video recorder (Figure TV -3) are amagnetic tape, some kind of tape transportmechanism, and the recording (or playback )

1101camera camera

signal

( /)tapetransport

magnetictape

magnetichead

11.1.1111.

FIGURE TV-3Elements of a video tape recorder

head. The recording head converts the modu-lated electrical signal from the camera into avariable magnetic field which impresses a pat-tern of magnetization into the magneticallysusceptible coating on the recording tape.

13

Playback of the recorded signal is accom-plished by passing the magnetized tape acrossthe head. As the head moves past the tape, thevarying magnetic field generates a modulatedoutput voltage which controls the electron beamscanning the monitor screen.

Video recorder heads A video recording head,like that of an audio recorder, consists of a mag-

netic element interrupted by a nonmagnetic gapacross which the tape passes. The width of this

head gap is important because it is related di-rectly to the upper limit of recordable signalfrequency:

tape speedhead gap

maximum recordable signal frequency

Heads can be manufactured to record high fidel-

ity sound ( 20,000 cycles per second) at tapespeeds of 71/2 inches per second or less usinghead gaps of the order of five microns, but goodvideo recording requires response in excess offour megacycles. Fixed head video recordersoperate very much as do their audio counter-parts and in principle represent the simplest andtherefore the most inexpensive recorder mechan-

ism. Nevertheless, they require either exceedinglyhigh tape transport speeds or an extraordinarilynarrow head gap. Although prototype fixed head

machines have been demonstrated, no manufac-turer presently markets one. Attention is nowfocused on the development of ingenious rotat-ing heads which provide high effective tapespeeds at an economical rate of tape transport.Rotating video recorder heads Portable record-ers utilize tape wound around a rotating headin a helix ( Figure TV-4 );

or a segment of a helix ( Figure TV-5 )

14

FIGURE 'TV-4Full helical-wrap rotating head for video recorder

FIGURE TV-5Diagram of a video tape recorder with a partial helical-wrap

rotating head

The tape travels past the recording head at arelative slow speed while the recording headrevolves rapidly ( 1800 - 3600 r.p.m. ) in the op-posite direction. This system ( "slant track re-cording") places the video signal on the tape as aseries of diagonal lines ( Figure TV-6) at a "writ-ing" speed of perhaps 680 inches or more of tapesurface per second.

FIGURE TV-6Illustrating a slant track video tape recording

Although helical scan recorders generally donot meet the standards of studio machines inbroadcast television, they are entirely adequatefor all but the most critical high resolution edu-cational applications and at the same time offer

simplicity, dependability, and portability at alow price. Helical scan recorders using magnetictape either one or two inches wide can give pic-tures sufficiently sharp for scientific uses.Image sharpness in video recordings The mostsignificant figure used to describe the merit ofa television system is its horizontal resolution

i.e. the number of vertical lines than can be dif-ferentiated in the width of the picture. ( Linesresolved by a system should not be confusedwith the number of lines scanned by the cameraor monitor.) The best commercial broadcasttelevision systems resolve 350 lines, but 300line resolution on a home receiver is consideredexcellent. One-inch tape recorders of the typeconsidered should resolve over 300 lines and ahalf-inch tape recorder should approach 200 lineresolution.

Image sharpness on the monitor screen is asubjective quality that depends not alone on lineresolution. Lighting and subject contrast alsoaffect sharpness. Inexperienced video photog-raphers can profitably study techniques used byfilm photographers. Since the image on a view-ing screen is influenced by the quality of eachcomponent in the total system, equipment ofcomparable quality throughout is recommended.It would seem unwise for example to use a cam-era capable of resolving 800 lines with a tapereporder capable of only 200 lines of resolution.Editing, Interchangeability and Standards Un-needed footage can be edited from video tapeby two methods. The first involves recordingthe information from one tape to another,omitting the unneeded portions in the transfer.The edited copy will contain very short periodsof "snow" ( noise) indicating the stopping of therecorder at the editing points. The secondmethod of editing involves physically cuttingand splicing the tape. Inexpensive tape splicingblocks can be made in the machine shop. Splic-ing instructions are supplied with the recorders."Electronics Editors" are supplied with expen-sive recorders.

While tapes usually can be transferred fromone tape recorder to another of the same manu-facturer without significant loss of picture qual-ity, it is not possible to interchange tapes be-tween recorders made by different manufac-turers. This is because the design of the videorecorder heads varies considerably among man-ufacturers.

Since few standards are available to assureconsistent reproducibility of tapes made onhelical-scan recorders, the AC, has preparedstandard tapes for the AMPEX and SONY re-

..MmaramMIM

corders. These tapes contain stair-step, Multi-burst and Windowed-sine squared test patternsand are designed to standardize resolutionmeasurements and to aid in instrument adjust-ment. Copies of these tapes are available. Theiruse should help make possible the exchange oftapes from one school to another with a mini-mum loss in picture quality.

SELECTED REFERENCES1. Closed Circuit Television-Definitions: Electronics

Industries Association, 11 West 42nd Street,New York 36, New York ($1.00)One hundred and thirty definitions, formulatedby EIA Engineering Committee on Closed CircuitTelevision are listed. Ranging from "AspectRatio" to "white compression," the definitionscover terms one will encounter in using videoequipment.

2. Fundamentals of Television and Essential Optics(EBI-3711), General Electric, Electronics Park,Syracuse, New York, 1964. (8 pages, free)

3. Fundamentals of The Vidicon Tube and Transis-tor Characteristics (EBI.3781A) General Elec-tric, Electronics Park, Syracuse, New York, 1964(7 pages, free)

4. Enger, Richard A. (ed.) Teaching with Videotape.St. Paul, Minnesota: Dept. of Communication,3M Company, 1961 (free)The value of this publication is limited by thedevelopments in video tape recorders since1961.

5. Lewis, Philip. Educational Television GuideBook. New York: McGraw-Hill, 1961. ($5.50)A textbook for the serious student of educationaltelevision. Closed circuit television is treatedin detail.

6. Schaefer, Chris H. and Suzman, Cedric L. VideoTape Recording, Hobbs, Dorman & Co. Inc. NewYork, 1965 ($12.00)A comprehensive and carefully documented re-port on "Video tape recording" with latestinformation on video tape technology and record-ing equipment. An instructive book for the com-munications industry, the business man, and thegeneral public. A comprehensive bibliography isincluded.

7. Wade, Warren L. Television Tape Recording Sys-tems: A Guide for School Administrators, Janu-ary, 1964. Reprinted by Ampex Corporation,Redwood City, California (free)An examination of portable television tape re-corders as they relate to school district needs.

15

t

I 11

0

FILMS AND

NEW USES FOR FILMSThe mechanical and logistical problems asso-

ciated with integregation of films as part of alecture often have been a deterrent to their use.Obtaining a projector ( and often a projection-ist ), threading it, insuring that it is operatingproperly, and that the film will be successfullyrun without a breakdown, are conditions noteasily met. Too often the classroom showing be-comes a parody on the debacle commonlycalled home movies. Nor does the solution ofthe mechanical problems end the difficulties.The majority of films which have been availableon chemical subjects were not designed forclassroom use, and certainly not for classroomuse in the light of the subject matter as it isbeing presented today.

Considerable evidence is accumulating whichsuggests that if the mechanical problems can besolved, and if the instructor can be continuouslyinformed of the sources and availability of goodfilms, he will indeed use them in his classroom,or in other segments of his course.

In recent years, the film industry with thehelp of educational research groups has madeunprecedented progress in minimizing mechani-cal and logistical problems. Projectors are al-ready on the commercial market which acceptcartridges containing film ready to project.Cartridge-loading projectors for short films ( ofthe order of four minutes) or for films ( of theorder of half an hour) are available. The projec-tors are quite small, reasonably priced, and canbe left in the classroom, laboratory, or studycarrel most of the time. The cartridge merely isinserted into the machine, the film is shown andthen is immediately ready for projection again.Even projectors for very large classrooms nowcome equipped with automatic film threadingand rewind attachments. By means of remoteControls located at the lecture table, these pro-jectors can be turned on or off, restarted, re-versed, or so controlled that a single frame offilm can be held on the screen.

Most films nowadays come with sound. Somehave provisions for addition of a second soundtrack by the user. Instructors should be encour-

FILM LOOPS

ab

aged either to supply their own sound track orto turn off the sound on a motion picture andtalk. While it may be difficult when usinga long film to synchronize one's own commentswith what is going on in the film, the instantane-ous stopping mechanism on the newer projectorsenables the teacher to hold on one frame, to dis-cuss a point appropriately, and to resume themotion when ready. The versatility of modernprojectors is encouraging the production of sin-gle-concept films in which synchronization be-tween the sound and the picture is much lesscritical than in traditional teaching movies.

A growing number of films particularly de-signed for college classroom work and for thelevel of work which currently is being exploredat the college and university level, is becomingavailable. Whereas in the past there were essen-tially no films potentially acceptable beyond thefreshman level, it appears very likely that theresoon will be films which can be used at any level,including graduate courses. As chemistry be-comes more abstract, as instruments becomemore complex and more important, as it becomesessential to expose the student to a wider andwider range of ideas and equipment which can-not easily be brought into the classroom, filmswill become more and more important. Alreadyfilms are being prepared in which the studentcan see experimental data being obtained andcan collect from the screen information whichhe can then work up and from which conclusionscan be drawn.

As indicated earlier, motion pictures also arebeing used: a) to present specific chemical prob-lems to which student viewers may proceed toseek solutions; b) in the laboratory to illustratespecific techniques or to provide visual instruc-tions for operating or for understanding theprinciples associated with the operation of aninstrument; c) in study carrels equipped withcartridge-loading projectors by means of whicha student may privately view a film as manytimes as he wishes.

This section has been prepared to assist teach-ers who wish to learn more about these new

VW*

.00

The reaction of potassium with chlorine photographed ,fron;CHEM Study color film "Chemical Families."

directions in the utilization of films in collegechemistry instruction. It includes:

Some specific examples of new uses of filmsand film techniques as they apply to collegechemistry.

A list of sources of films, film loops and re-views of films.

A summary of the equipment currently avail-able including sources, approximate prices andthe background information needed to helpmake an intelligent selection and wise use ofhardware.Some specific examples. Films might be classi-fied conveniently in terms of their intended usein teaching ( pedagogical techniques ), or interms of the special visual effects they illustrate( film techniques ). The latter are familiar fromcommercial movies; examples include close-ups,

TABLE

stop-action, time-lapse. Examples of the formerfollow.

Single concept films. These are short, usu-ally four to ten minutes, films on a single topicsuch as vapor pressure, enthalpy, hexagonal andcubic closest packing, pH, the discovery ofoxygen-18, etc. Single concept films may be usedas part of a classroom presentation or they maybe assigned for independent study. Studentsmay borrow, from the instructor or from thelibrary, cartridges containing assigned films andview the films from projectors located in studycarrels. Alternatively, the projectors with cart-ridges inserted and ready for use might be lo-cated in halls of the buildings, in laboratories, orin small classrooms. Some single concept filmsnow available or in preparation are listed inTable F-1.

F-1

Some Single Concept Films Available or In Preps,

Tide Producer and characteristics

Infrared Spectra andMolecular Structure

Interpretation ofVibration Spectra

An Electrochemical Cell(Animated Mechanism)

A Silver-HydrogenElectrochemical Cell

Molecular VibrationSusing Models

Atomic and BondingOrbitals

Crystal Structureof Metals

Siabaugh-Ouellette; 4 minutesechnicolor cartridge

Slabaugh-Barrow; 2 four minute!pops, Technicolor cartridge

efampbell-CHEMS, 4 minutesTechnicolor cartridge

Campbell-CHEMS; 4 minutes,Technicolor cartridge

tampbell-CHEMS; 4 minutes,`Technicolor cartridge

Slebaugh- Parsons, 4 minutes,Technicolor cartridge

Slabaugh; 4 minutes,Technicolor cartridge

Availability

February 1967

February 96

FobruorY 196/

AC3, February 1967

February 1967r

AC3, February 1967

AC3, February 196

Filmed lecture experiments. Chemists em-phasizing experimental methods in their class-room teaching may have found that the class-room is too large for all students to adequatelyview what is taking place in the experiment onthe lecture table. They also may have found thatthe equipment necessary to carry out the experi-ment appropriate to the class discussion was in-accessible to the lecture room for reasons of

cost, safety, size, geographical location, sensi-tivity of the instrument, conflict in use, or timerequired for preparation of the experiment. Pos-sibly the time factor in the performance of theexperiment is either greater than the time whichcould be devoted to the experiment in the class-room or too short for effective observation bythe students. Under these circumstances filmedexperiments might be most appropriate.

19

.1110=1.

Lecture experiments on film might be pre-pared locally or purchased. They might beutilized:

1. To serve as the focal point for a dialoguebetween the teacher and the students, oramong the students, preferably in the class-room, concerning the meaning or inter-pretation of the experiment. Such dialoguesgenerally involve the analysis of the dataor observations. They also may involve dis-

cussion of experimental techniques utilizedin the experiment and of the possiblesource of experimental error and the in-fluences of such errors on the experimentalresults.

2. To serve as the method of enabling the stu-dent to make the observations and to takedata from the instruments used so that hemay then analyze and interpret the experi-ment himself even though he did not actu-ally perform it.

TABLE F-2

Some Lecture Experiment Films Available or In Preparation

This Producer and Characteristics Avelibili(y........--.

PotentiometricTitrations

Ionization Energies

Distribution of Molecular Speeds

Electronic Spectra of 160 and 160

Mass Spectrometric Determinationof Mass and Relative Abundancesof Isotopes of an Element

,Slabaugh; 4 minutes,Technicolor cartridge

AC., february 1967

Fall 1967

1967

Fall 1967=

Utilization in the laboratory. Whereas filmsmay be utilized in the classroom to give everystudent a "front row" seat, filmed and tapedmaterial may be used in the laboratory: a) togive every student individualized instructionwhen and where it will be most appropriate tohis laboratory experience; b) to better organizelaboratory instruction; and c) as the media forimproved laboratory examinations. Mechanicalproblems associated with such uses of films inthe laboratory have been surmounted by usingcartridge-loading 8 mm projectors, both withand without synchronized sound. Using a rear-screen attachment on the projector, the film maybe viewed in natural light as is a televisionscreen. These projectors may also be purchasedwith earphones so that several units may be em-ployed in a small room without audio interfer-ence.

Short films in which various laboratory opera-tions are shown in a step-by-step fashion arebecoming available. Examples are given in Table

20

F-3. Instructors may now refer students tofilmed examples of techniques, equipment utili-zation, or instrument operation as necessary andappropriate to the student's work. Only thosestudents who are in need of this particular in-struction or information need be required tospend their time viewing the film.

In general, filmed and taped materials maybe effectively employed to complement labora-tory teaching in four ways:

1. To illustrate and standardize laboratoryoperations that is to assist in the "tellingand showing" function of the laboratory.An important example here is that colorstandards such as endpoints for indicatorscan be faithfully reproduced on film withsome effort. In addition magnification andframe-slowing techniques make portions ofthe equipment and intimate details of proc-esses vividly accessible. Safe practices andsafety precautions also can be forcefullyimpressed on students with striking pic-tures.

2. To extend the scope of the laboratory workby presenting, to the student, additionalexperiments in which data and observa-tions are generated and for which the stu-dent makes the analysis and interpretationby himself.

3. To move from verbalized quizzes and ex-aminations toward laboratory practical ex-aminations without becoming involvedwith massive logistical problems of admin-istration of the examination.

4. To individualize instruction that is to pre-sent the individual student with the in-formation he needs in the laboratory atthe time it will be most beneficial to hislearning.

In courses where students are rotated amongexperiments, films on laboratory techniques andoperations can remove a large burden from theinstructor thereby enabling him to work closerwith the students in examining the significanceof the laboratory work.

TABLE F-3

Some Laboratory nstruction Films Available or n Praparation

Titration

Basic LaboratoryTechniques

Thin LayerChromatography

Technique_s of YolurletricAnalysis

Using A Filter

Quantitative Transfer

Producer and Characteristics Availability

Slabaugh; 4 minutesTechnicolor cartridge

Barnard; 5 minutesFairchild cartridge

rnard; 6 minutes'Irchild cartridge

University of Wisconsin;sound, 30 minutes,16 mm reel

Yale University; 2 minutes

Yale University; 17 minutes,sound

February 1967

rA011e June 1967

Os, June 1967

U. of Wisconsin1(eilevision Center

Association Films

Association Films

TABLE F-4

Some Instrument Instruction Films

,Titts Producer and Characteristics Availability

(A

Operation of the,

Mettler. Balance

Single Pan Sartorius ,

Balance

Operation of theBeckman IR8 Spectrophotorneter

'Operation of the,.

B. and L. Spectronic 20

peration of the Vapor,

; Jr 4 .,

Slabaugh; 4 minutes,Technicolor cartridge

Slabaugh; 4 minutesnicolor carttidge

Ouellette; 4 minuteTechnicolor cartridge

Ace February 1967

, 1 ary 1947 ,

i'Apri11967

Fell 1967,, ,

II I

*

21

11=11111111/

hiInstrument instruction films. These films

show the student the details of construction andoperation of an instrument, as well as some ofthe basic laboratory techniques and safety pre-cautions pertinent to its successful use. In prac-tice a cartridge-loading projector containing thefilm is placed beside the instrument in thelaboratory. A student views the film or portionsof it any time he feels the need. With such films,the usual check-out period for an instrument( e.g. UV, IR, nmr, Raman, etc. ) can be greatlyabbreviated or eliminated. Examples of instru-ment instruction films now available or in prep-aration are given in Table F-4. ( See page 21. )

Laboratory examinations via films and tapes.Films and tapes offer two significant break-throughs in laboratory examinations. First, theyallow the instructor to move toward laboratoryexamination. Secondly, they allow him to evalu-ate student learning and understanding ofvarious parts of the experiment. Such evaluationmay be used either for grading purposes or forapproval to proceed to a situation of greatercomplexity.

Items which have been used or suggested forfilmed or taped laboratory examinations include:1) the prediction of the effects of changingvarious experimental parameters; 2) the designof an experiment to test a hypothesis; 3) theformulation of an hypothesis from the evidencepresented; 4) the ordering of data; 5) the designof experiments to achieve a specific objective;6) the determination of knowledge of experi-mental tools; 7) specific observations; 8) thesurveillance of errors in technique; and 9) theidentification of laboratory operations andequipment.

In addition to films, slides and transparenciesalso have been used as mechanisms for adminis-tering laboratory examinations.

Films for non-scheduled time. Some instruc-tors assign a given film for out-of-class viewingprior to the consideration of the topic in theclass, just as they would make an assignment inthe textbook. The film treatment of the subjectthen serves as the basis for the class discussion.

In selected cases, solutions to problem setsand examinations are available on slides or film

strips. Synchronized sound techniques may be

22

The reaction of xenon with platinum hexafluoride. Photo-graphed from the color film "Xenon Tetrafluoride," pro-

duced by Argonne National Laboratories.

used to explain the solutions to the problemsand questions. This may also be done for samplecalcualtions from experiments.

Another technique is to put the lectures onaudio-tape or on film with sound. In such in-stances, students absent from lecture and thosewishing to clarify their understanding of classmaterial may do so. Such out-of-class viewingprograms have been operated in one of twoways: 1) space is provided within the depart-ment for the projection and listening devices;2) instructional materials are available throughan audio-visual center. In such facilities a stu-dent may be able to dial and see any of a varietyof films stored in the audio-visual center.

Coordinated use of different film and tapematerials. Several instructional experimentsnow are underway which make available to theinstructor in his classroom or to the students inlaboratory-study carrel combinations the capa-bilities of several media films, sound TV tape,overhead projector.

One of the most successful of these is theaudio-tutorial laboratory developed by S. N.Postlethwaite in the Botany Department at Pur-due. In this laboratory, the student has at hisdisposal in addition to the usual botany labora-tory facilities, study carrels containing film pro-jectors and audio tape recorders. Each student

An electron density map of molecular structure and a fieldemission microscope picture of a platinum crystal. Photo-graphed from the color film "Electronic Processes in Crys-

tals" produced by Tokyo Cinema, Inc.

comes to laboratory when he wishes and whilethere proceeds at his own pace.

In the study carrel, the student listens to au-dio tapes specially prepared by the instructorfor the unit or experiment under study. Instruc-tions on the audio tape may direct the student tothe laboratory bench or to view a film also pre-pared especially for this use, or to a readingassignment. If a student needs help, he can ap-proach an instructor on duty in the laboratory

TABLE

for this purpose. Each student gauges his ownprogress with quizzes winch either send himforward to new materials or back over some ofthe same material. A chemistry program similarto this is now in progress at Cornell.

Many schools now have lecture rooms equip-ped with facilities for slide, film, TV and over-head projection. Instructors can control any ofthese from the lecture table or may use anycombination in a given lecture. One techniquefrequently used in these classrooms is to displayrelated information on two screens simultane-ously. The instructor then shows the relation-ships or draws comparisions between the infor-mation appearing on the two screens.

Ancillary materials for films and tapes. Becausestudents often do not take notes during a film ortape presentation, many instructors have foundit especially helpful to prepare study guides orquizzes which students may take with them.Making these materials available for study be-fore viewing the film sometimes helps a studentbecome more alert to the important conceptspresented and may encourage him to search foranswers to questions as he views the film.

Teachers preparing films for distribution areurged to supply resource guides for these films.In this way potential users can know the pur-pose and content of a film and may gain infor-mation that will enable them to use it moreeffectively.

Filming techniques. Many of these techniqueshave been used effectively in chemistry films asthe examples in Table F-5 illustrate. These ex-amples should prove particularly useful to thoseplanning to make their own teaching films.

F-5

Ostel growth, iheinitielAssolution,,.41;rystal growth, cniital struCture;\ei

ing of instrumentsssottrOg a saallt, MOSOLliarY

23

Tr,

SOURCES OF CHEMISTRY FILMS

In the past no concerted effort has been made to

prod a carefully-edited catalogue of existing

chemistry films with useful reviews. Hopefully such

a catalogue will be available during the next year.

Film Directories1. Index of Chemistry Films (Fourth Edition)

Royal Institute of Chemistry30 Russell Square, London W.C.1, Eng.

This index is the most comprehensive listing

of films on chemical topics currently avail-

able. Approximately 1400 films and 400 film-

strips from more than 200 sources are in-

cluded. The fourth edition lists films produced

through September 1964. Designed for use by

schools, technical colleges, universities and

the training departments of industrial firms,

this index includes offerings from the USA,

United Kingdom and 20 other countries. It

contains 127 film subject classifications and

77 film strip classifications and costs approxi-

mately $1.10 prepaid.2. Film Guide on Chemicals, Chemistry, and the

Chemical Industry, 1965.66 EditionManufacturing Chemists' Association, Inc.

1825 Connecticut Avenue N.W.

Washington, D. C. 20009

List contains 311 films from 100 sources

covering many facets of chemistry, chemicals

and the chemical industry, and suitable for

many audiences including college students.

3. United States Atomic Energy Commission 16

mm Film Catalog, Professional Level, 1965

Audio-Visual BranchDivision of Public Information

U.S. Atomic Energy CommissionWashington, D. C. 20545

186 professional-level technical films are

made abailable from ten domestic USAEC film

libraries on a free loan basis for educational,

non-profit, and non-commercial viewing. List-

ing includes title, date, time, sound, color,

producer, sale and loan information plus a

comprehensive paragraph summary of the

subject content of the film. "Understanding

the Atom Series", and the "1964 Geneva Film

Series" are available from this source.

4. Argonne National Laboratory Catalogue of

Motion Picture FilmsFilm Center, Bldg. 2Argonne National Laboratory

9700 So. Cass Ave., Argonne, Ill. 60440

24

List contains 92 films produced by and for the

Argonne National Laboratory covering topics

ranging from the general nature of the Ar-

gonne Laboratory to specific experiments

recorded for highly trained experts. Films are

available on loan at no charge (other than re-

turn postage and insurance). Listing includes

title, catalogue number, date, time, sound,

and color information plus a paragraph sum-

mary of the subject content of the film.

5. Films on The Nuclear Sciences (1966 cata-

logueNational Science Film LibraryCanadian Film Institute1762 Carling AvenueOttawa, 13, Ontario, Canada

Summaries of 254 films are available from the

Canadian National Science Film Library. In-

formation is given on each film including

country and production date, length, whether

black and white or color, language versions

available, producer and sponsor, technical or

scientific adviser, description of content, and

service charge or rental. The sections on gen-

eral theory and principles, chemistry and

metallurgy, and radiation and radioisotopes

contain details on many films suitable for use

in colleges and universities.6. Bureau of Mines Films, 1965-1966

MOTION PICTURESBureau of Mines4800 Forbes Ave., Pittsburgh, Pa. 15213

Tabulation includes information on 40 films

with many relevant to the technological as-

pects of chemistry. These films are available

from the Bureau of Mines without charge ex-

cept for return postage. List includes informa-

tion on film title, time, mailing weight, pro-

ducer of the film, and a summary of the film

content.7. Source Directory: Educational Single-Concept

Films Available in Magi-Cartridges (Third edi-

tion, March 1966)Commercial and Educational Division

Technicolor CorporationBox 517, Costa Mesa, California 92627

This is a current list of educational film pro-

ducers and respective listings of single-con-

cept films available in Magi-Cartridges for

use in Technicolor Standard 8mm and

Super-8 Instant Movie Projectors. It includes

66 titles on chemical topics available from

seven sources.

Other Film Sources

Several series of films, film strips, and trans-parencies have been prepared for the chemistryclassroom and are not completely reported in thedirectories just described. Most of these films havebeen prepared for beginning chemistry classes orfor the in-service education of secondary schoolteachers.

Motion Pictures with Sound1. Modern Learning Aids

Division of Modern Talking Picture Service,Inc.

3 East 54th Street, New York, N. Y. 10022This source offers 26 CHEM Study ChemistryFilms (available in both 16mm and 8mmsound cartridge formats). In addition 11 filmson chemistry laboratory techniques (availablein 16mm), and three films titled "The Chemi-cal Elements" (available in 16mm) areoffered.

2. Coronet FilmsCoronet Building, Chicago 1, IllinoisCoronet offers the University of Akron Chem-istry Laboratory Series (available in 16mmform), consisting of twenty-seven films andthe Coronet Chemistry Films set (available in16mm form), a series of twenty-one class-room films.

3. Encyclopedia Britannica Films, Inc.1150 Wilmette AvenueWilmette, Illinois 60091The Chemistry on Film Series (available in16mm form) consisting of one hundred sixtyfilms is offered.

8mm Film Loops, Short Form, Silent1. Advisory Council on College Chemistry

Teaching Aids Committee Film ProjectChemistry Department, Stanford UniversityStanford, CaliforniaApproximately 10 films have been producedat Oregon State University by W. H. Slabaughillustrating what a chemist with ideas and aminimum of equipment can do to produce8mm film loops designed for use in the col-lege classroom. Approximately 10-singleconcept films have been made by J. A. Camp-bell by extracting relevant footage fromCHEM Study films. Five single concept filmshave been made by S. A. Schrage by excerpt-

7.1..:

..1110,

ing footage from existing films. These filmsare available only for examination and stimu-lation purposes at the present time.

2. United Nations Educational Scientific andCultural Organization

Pilot Project for Chemistry Teaching in AsiaDivision of Science Teaching, UNESCOPlace de Fontenoy, Paris 7e, FranceApproximately 10 films, generally dealingwith experimental topics treated in an"open-ended" manner have been made.Some emphasize the continuous variationmethods developed in the Chemical BondApproach.

3. The Nuffield FoundationScience Teaching ProjectMary Ward HouseTavistock Place, London S.C. 1Thirty-eight films have been prepared tosupplement the new "0" level (secondaryschool) chemistry course development byNuffield; this list includes loops on labora-tory techniques, theoretical concepts basedon experimental observations, measure-ment, industrial processes and uses ofchemicals.

4. Association Films, inc.600 Madison Ave.New York, N. Y. 10022Sixty-three chemistry films produced atYale University are available with sevenshowing demonstrations on the preparationof oxygen, six showing demonstrations re-lated to physical and chemical changes, andtwenty-two on miscellaneous topics includ-ing laboratory techniques, basic principles,and structure.

5. Genco Educational Films1800 Foster Ave., Chicago, Illinois 60640Five flms related to the detection and effectsof nuclear radiation are offered.

6. Encyclopedia Britannica Films, Inc.425 North Michigan AvenueChicago, Illinois 60611Five films related to states of matter andproperties of matter and eight describinglaboratory techniques in chemistryare avail-able.

25

- -,,y,w_LA2NuagaiwagiUiliatr.11

1......Mr

4m.m.....

&7. Sutherland Educational Films

201 N. Occidental Blvd.Los Angeles, California 90026Four films on some fundamental chemical

concepts are listed.8. Gateway Educational Films Ltd.

470.472 Green LanesPalmers Green, London N. 13, EnglandThree films on paper chromatography, thin-

layer chromatography, and electrophoresisare offered.

9. Ha las and Batchelor Cartoon Films, Ltd.

Lysbeth House10A Soho SquareLondon, W. 1, EnglandEight films on atomic and molecular struc-ture are scheduled to be released in 1966.

10. International Visuals Aids Center691 Chaussee de MonsBrussels 7, BelgiumSixteen films on technological topics re-lated to chemistry have been made.

Transparency Sets1. John Colburn Associates, Inc.

P.O. Box 12361122 Central Ave.Wilmette, Illinois 60091Tecnifac Overhead Projecturals offer a gen-eral chemistry set of fifty-nine projectuals(with overlays) and a 48 page teacher's guide.

2. Keuffel and Esser CompanyHoboken, New JerseySpectra transparencies for the overhead pro-jector for chemistry are offered. This is a set

of eighty transparencies (with overlays).

3. General Aniline and Film Corporation140 West 51st St.New York, New York 10020Projecto Aid Transparencies consisting of achemistry set of five transparancies are

offered.

2 x 2 Inch Color Slides

1. Geographical Slide Service

845 Outer DriveState College, Penna. 16801Slides on minerals and manufacturing sub-

jects are available.2. American Museum of Natural History

Central Park West at 70th StreetNew York, N. Y. 10024Slides on snow crystals, common rocks, and

minerals are available.

26

Apparatus used in the preparation of xenon tetrafluoridewith a photograph of the oscilloscope trace of the productidentification in the mass spectrometer. Photographed fromthe color film "Xenon Tetrafluoride" produced by Argonne

National Laboratories.

EQUIPMENT: ITS AVAILABILITY AND USES

Basic to the renewed interest in using film in

the chemistry classroom and laboratory is theintroduction by the industry of unproved film,

film formats and complementing hardware.With these new developments comes an in-creased need for the chemistry teacher to under-stand not only the capabilities of the new hard-ware but also some of the important principlesof projection. Included in this section is infor-mation on film formats, projectors and theircharacteristics, sound screens and some new de-velopments in still projection techniques. Theaim here is to provide a handy guide for the pur-chase and the setting up of equipment so thatthe best results can be obtained.Film types. There are currently four forms of

8mm motion picture films on the market in addi-tion to the traditional 16mm format. These arethe regular 8mm, Super-8, Format M and a Jap-

anese product. Of these the regular 8mm andthe Super-8 have been used most extensively inteaching films.

The image area on the Super-8 film is 52 per-

cent larger than that of the regular 8mm. Con-

sequently the Super-8 format offers a brighterand sharper picture than that obtained from a

regular 8mm material under comparable condi-tions. Both regular 8mm and Super-8 can givemagnetic sound prints with a quality comparableto present 16mm optical sound. Because thesprocket holes are smaller and further apart onSuper-8 film than on regular 8mm film, each ofthe 8mm formats requires its own projectors andcameras. However, several manufacturers offerequipment which can be converted from regularto Super-8 with minor adjustn-.?nts.

Saw Front ScreenTechnicolor Model 500 (cartridge load

..

silent).Technicolor Corp., 1985 Placentia ".Ave., Costa Mesa, Calif.

Fairchild Mark V (cartridge load0Ond).'

Fairchild Camera and InstrumentCorp., Industrial Products Dives le750 Bloomfield Ave., Clifton, 14:: 00

Rolex 18.5, Auto load, silent .50

Supor4Imm, Front Screen

Technicolor Model 510. (cartridgeload, silent).Technicolor Corp., 1985 PlacentiaAve., Costa Mesa, Calif. $ 99650.

Eastman Kodak M90 Reel load, silent.Eastman Kodak Co., Apparatus andOptical Div., 343 State St., Roches-ter, N. Y. $1

EnStrnan Kodak M00 Reel load,

The running time of the 8mm films is approxi-mately twice that of the 16mm. For example atsilent speed ( 18 f.p.s. ) 100 feet of 16mm filmwill run in about 4 minutes while only 50 feetof regular 8mm film will run in about the sametime.

Projectors. Table F-6 gives some examples offilm projectors, their important characteristicsand manufacturers.

TABLE F-6

n Kodak CAIOptical Div., 343 Stet,

6. N. Y.

Bauer T1-S, Quartzsound can be.

addif,

tape recorder

OM. OW SWOONSOO 0011$0i0 VI

?'

Fairchild Mark IV (cartridgesound)

Super 8-mm, Rear ScreenNot available as single unit; must

combination unit; see papa

iinin, Front Screen1' Bauer P-6 Auto load, quartz Is bulb

magnetic and optical sound. $1250.00

1 Bell and Howell Auto load 552 $755.00

Sell and Howell 302-M magnetic sound $950.00

Gratin Model 815 manual threading $625.00

tRCA Safethreader No. 1600 .00

*Eastman Kodak AV105mm masound

Victor Mag-3 magnetic sound

Special Purpose ProjectorsMegnetic Sound Technicolor Model

;09 projector. No. TMT 25 telassil $41

ikelert Soundstrip 35mM 'OritintIC'Sound filmstrip.The Mint Co., inc., Huftenkrs'Sti

'Caw

,Impot C0114. Sq9 Perk 104,041r#,Y*&* Yt:*II and Howell the!i, Selo Ce,1100,A*Cermikked, Chiceip,

afi

liOnoflax, Inc.. 3730 Monroe Ave, Rotheito, KY.4,,,Ftltro Co". l'reet. end Cooper

. 1P4,0

10111000,,1004fritdalallineit.iiii* Yedt

27

8mm front (wall) screen projectors. The home

variety of projectors which utilize regular 8mmfilm generally are not suitable for front screenprojection in classrooms. The Bo lex Model 18-5($200.00) is an example of a high quality pro-jector which has been used successfully for this

purpose. Among the cartridge loading projec-tors, the Technicolor Model 500A offers an in-expensive regular 8mm projector ( $85.00) with

still picture capabilities, without sound. Thisprojector takes a four-minute cartridge. Themanufacturer indicates that it will give a satis-factory 30" by 40" image in a darkened roomon a wall screen. It has been used for frontscreen projection in small areas under carefully

controlled conditions.

A comparison of regular 8mm, Super 8mm and 16mm filmformats. The shaded areas indicate the space available for

the sound tracks.

Super-8mm front screen projectors. Here theteacher has a choice of supporting models withimproved light sources and lenses. The EastmanM-90, reel type ($180) or the Bauer ( $179.50)

are examples of Super-8mm prcfector design.

The Eastman M-100 projector has magneticsound capabilities, and, in operation, offers suit-

able performance in the small classroom. It iscomparable in price to 16mm sound projectors.

The Technicolor 510-A ($90.00) is the only Su-per-8 cartridge load projector on the market atpresent. It has no sound capability and takes a

four-minute cartridge.16mm front screen projectors. Considerable

improvements have been made in loading char-acteristics and light output of 16mm sound pro-jectors in recent years. These improvements fa-

28

cilitate immediate classroom use of films and

film segments. The simplified operation, and im-proved picture, will be of interest to those whohave not examined the new models. Auto-load-

ing characteristics are such that the inexperi-enced instructor or teaching assistant can get apicture on the screen in a matter of seconds with

an absolute minimum of training. Examples of

this equipment include:

Bell and Howell AutoloadModel 552 $ 755.00

RCA Safethreader Model1600 "Safethreader" $ 617.00

Graflex Model 815(manual loading projector) $ 625.00

Bauer P-6 Autoload, incadescentor quartz 12 projection bulbsavailable 51250.00

The following projectors offer a combinationof optical and magnetic sound reproductionfeatures. They also have a feature which permitsthe user to add his own sound track to the film( magnetic recording feature).

Bell and Howell Filmsound 302 M $950.00

Eastman Kodak Model AV-105M $885.00

Victor Mag-3 $670.00

A Technicolor projector and film cartridge.

Sound conversion units are available to providemagnetic sound recording and playback capa-bilities for existing equipment. The GregorySound Conversion Unit sells for $195.00 plusinstallation. For a discussion of magnetic andoptical sound, see below.

8mm rear screen projectors. A self-containedrear screen and projector for 8mm film resemblesa small television set. The advantage of rearscreen projection is that it can be used in thenormally lighted laboratory or classroom. Cur-rent model projectors take cartridged film. Theyare extremely simple to operate requiring a min-imum of maintenance. The only projectors ofthis type now offered in the regular 8mm size,are the Technicolor Model 600AD ( $250.00 )and the Fairchild Corporation Mark IV projec-tor ( $495.00 ). The Technicolor projector usesa four minutes cartridge; the Fairchild projectortakes a cartridge which holds up to 22 minutesof color film. Magnetic sound is a standard fea-ture with the Fairchild projector. Color printsof the CHEM study films are available in cart-ridges for Fairchild projectors. One model ofthe projector is equipped with a magnetic re-cording feature ( model IVAV ).

16mm projectors for rear or front screens. TheKalart-Victor projectors use regular 16mm filmin combination which provide both front andrear screen projection capabilities.

441111.1,tas.

A Fairchild projector and film cartridge

I

Light sources. The General Electric Mark300 high intensity light source, available in manynew projectors, so increases illumination on thescreen that film can be shown under normalclassroom lighting conditions.

When considering the purchase of new pro-jection equipment which might be used in alarge lecture hall, suppliers should be given theroom dimensions, lighting conditions and otherfeatures in addition to the projector capabilitiesdesired. All such equipment should be tested inthe rooms in which it will be used before a pur-chase is made.

Rear screen projection cabinets. Good com-mercial rear screen projection cabinets are avail-able for use with a variety of projectors runningfrom 35mm slide to 8mm and 16mm movies. TheHudson Photographic Industries 8mm screen($17.00) and the H. Wilson Corp. 16mm screens( $150.00) are examples. For the the "do-it-your-selfer," the Eastman Kodak Pamphlet No. S-29REAR PROJECTION CABINETS offers excel-lent directions on local fabrication.

Sound characteristics of film. Conventional16mm sound film has an optical sound track inwhich the sound reproduction is stimulated bylight. Films now can be supplied with magneticsound tracks. Here the sound reproduction isstimulated by the interaction of a magnetizedstripe on the film with a charged head in theprojector. The magnetic sound stripe similar tothat on an audio type can be added to film priorto photographing. Sound can be recorded as thefilm is exposed in the camera, or it can be addedlater using projector with a magnetic recordingcapability. Eastman film, Kodachrome II No.KA558, can be ordered now from dealers. Acamera suitable for this use is discussed on page31. Probably more important to the teacher isthe fact that 8mm, Super-8 and 16mm film canbe shot silent and the magnetic stripe addedwhen the film is processed. This affords the op-portunity of adding a sound track to the film asit is run through the projector. Magnetic stripingmakes it possible to add a second sound trackto films with sound. Magnetic sound tracks canbe erased and corrected as with an audio taperecorder.

29

TABLE F-7

; ,

of internegative, printing effects, prints from A and BPrices do not include costslaboratories for specifics.

TABLE F-8

rolls, minimum charges, or discounts to schools. Contact the

'e,

Calvin111 R°141,01*.

it Offering 8mm *w

ge W. ColburnAklboratory, Inc.44North Wacker Drive

Chicago 6, Illinois

Ol4Ouvirne stories4076 Transport Street

Alto, 'C01,060114% 940

L4Xe Laboratories,Tenth Avenue `,.:*t

York 19, NewYork

Oral Film Laboratories1546 N. Argyle

iywood, California

lywood Film Enterprises#Sunset Boulevard

30

Inquiries concerning magnetic striping proc-esses and costs should be directed to the filmprocessors.Film costs. For those planning to make theirown films, Table F-7 gives approximate currentcosts for the printing of silent color films and foraddition of magnetic sound stripes. Table F-8lists some laboratories offering release printservice.

Cost of cartridging films. Cartridge costsrange from one to ten dollars ( based upon thekind of projector and on the quality ordered ).Technicolor Corporation now will furnish andload cartridges for their projectors at a cost of$1.00 when suitable 8mm film is furnished. Cart-ridges for the Fairchild projectors cost from $6.60to $9.95 and special film treatment for films longerthan 200 feet is necessary at a minimum cost of$4.00. Those desiring to have films put in cart-ridges are encouraged to contact the Techni-color or Fairchild Corporations directly.Cameras and lenses. Accompanying the intro-duction of the new film formats and projectorsare improved cameras. Cartridge loading of cam-eras with Super-8 film is simplified since the cart-ridge need not be turned when half the footagefilm has been exposed. Zoom lenses permit goingfrom a wide picture to a close-up and vice-versawithout stopping or moving the camera. Reflexcameras with "through-the-lens" capability al-low precision composing and focusing of close-ups. For photographing close-ups of laboratoryequiment or reactions, cameras with a retailprice of $75.00 or less probably will not giveacceptable steady picture quality.

Two professional cameras which are availablefor 8mm film are the Bolex H-8 ( $480.00 ), andthe Pathe DS-8 ( $900 ). The latter is the firstcamera to use a 100 foot double Super-8 filmspool. The Fairchild Model 900 ( $900) is nowon the market as a regular 8mm sound motionpicture camera.

Plastic lenses are excellent for some uses;however, experience has shown that glass lensesare more suitable in close-ups for chemistryuses. Cameras with fast lenses ( aperture notgreater than f/1.9 and able to accept accessoryclose-up lenses are a necessity for quality filmmakeup. Slower lenses restrict camera use in

&the usual low light situations encountered in thelaboratory.

Still projection systems. Several new still pro-jection systems which have appeared recentlyare described in the following paragraphs.

Filmstrip with magnetic sound. The Execu-graf ( $375.00) uses a film and a sound cartridge:the film cartridge contains up to one hundred35mm pictures, and the continuous loop soundtape cartridge has a running time up to twentyminutes. This projector has both the front andrear view facility.

Filmstrip with optical sound. The KalartSound strip projector ( $400.00) uses a continu-ous strip of film identical with a sound movieexcept that the picture and the accompanyingsound track are printed on alternate frames. Pic-tures, or slides with accompanying narration onaudio tape can be sent to the manufacturer forconversion to this format.

Slides with sound. The Hughes Video-Sonic( automatic control ) projector Model 901( $400.00) is a self contained rear screen projec-tor which accepts 35mm slides in 36-slide trays.It has magnetic tape for audio.

Audio attachments for slide projectors. Inmany cases it is possible to use existing equip-ment, or combinations of projectors and record-ers, to generate automatic presentations of slidesand sound. The Kodak Carousel Sound Synchro-nizer ( $20.00) enables the instructor to com-bine a stereo tape recorder of any type with aCarousel Model 700 or Model 800 projector.Slide-change signals are recorded on one chan-nel and the narrative on the other track. Onplayback, slides change automatically; this sys-tem is easy to connect and use.

A synchronized sound-film system. This isavailable for the Technicolor Model 800 Projec-jector, from Ealing Films or Auto-Sell, Inc.( $255.00 for projector and recorder ). Both tapeand film automatically stop when the end of thefilm loop is reached. It is possible to program thefilm loop for double or triple showing, usingup to 20 minutes of narration.

Special effects. The Kodak motion adapterunit ( $24.00) consists of a spinning polarizerwhich fastens on the front of any 35mm projectorlense and requires especially made slides which

31

111111101,

.111.

contain elements of polarizing material. An effec-

tive motion illusion is possible including continu-

ous or cyclic movement, rotation, vibration, andradiation. Technical Animations, Inc. can pre-pare motion slides on a custom basis. The Ameri-

can Book Company will be the distributor for mo-

tion slide series. Eastman Kodak, Audio-Visual

dealers, will handle orders for slides. Experi-mental kits of Technical Animation polarizingmaterials are also available from the dealers.Prototype slides showing vibration modes ofmolecules now are available.

Random access slide projector. One of thedisadvantages in using slides to augment lectures

has been that the lecturer is tied to an order of

projection not easily changed. This disadvantageis overcome with the appearance on the marktof random-access, 35mm automatic slide pro-jectors, such as the Dial- A-Slide projector( $700.00) or Eastman Kodak RA-950 projector( $785.00 ). Both projectors have controls whichtell the instructor which slide is being projected.

Similar units are available for connection todata retrieval systems.

UTILIZATION OF PROJECTED MATERIALS

Regardless of the quality of a motion picturefilm or slide, or the advanced state of the art inhardware, successful projection techniques re-main the key to transferring ideas and conceptsfrom the projected image to the students' mind.By following good practices in setting up a class-

room or laboratory for the showing of film, theinstructor gains the ultimate flexibility for utiliz-ing a slide or film clip in the lecture with the con-fidence that the class will receive the maximumbenefit from the medium.

This section is intended to help clarify someof the steps necessary to insure that the messagereaches the class without interference by theprojection process.

For effective projection in the classroom, con-sideration should be given to the following:

selection of a screen location, size, and type.

selection of the optimum projector location.

providing required image brightness.

general considerations of student comfortin the lecture room including light control,adequate sound facilities, and seating.

For the optimum use of projection during alecture there should be a minimum of equip-ment and facility adjustments. For all practicalpurposes, the screen should be in a fixed position

away from direct light sources and from areas

used more frequently, e.g., avoid if possible a

screen location where a roll-down screen coversthe chalkboard.

Under ideal conditions, the instructor shouldbe able to push a button and insert into the lec-

ture a film or slide for seconds or minutes asneeded, with absolutely no mechanical distrac-tions to the class.

Projection screens.' The screen is most often

the weakest link in using the projection systems.The efficiency with which the screen can trans-mit color brightness and contrast to the eye,affects the ease with which the point beingmade can be understood by the student. Follow-ing are brief discussions of screen types and

their suitability to classroom or laboratory ap-plications:

Matte screens. Matte screens diffuse light

evenly in all directions. Images on matte screens

appear almost equally bright at any viewing

angle. To avoid distortion because of viewingangle, however, viewers should be no more thanabout 30 degrees to the side of the projectionaxis, and not closer than two-image widths tothe screen.

Most matte screens are about 85% efficient.A metal finish matte screen will give valuablecolor correction to pictures where true renditionis important. A form of matte screen can be asmooth wall painted white, although it should beviewed critically before accepting it for class-room use.

Lenticular screens. These screens have a reg-

ular pattern of stripes, ribs, rectangles, or dia-mond shaped areas. The pattern is too small to

see at viewing distances for which the screen isdesigned. The screen surface may appear to beenameled, pearlescent, granular metal, or

smooth metal.

*Most of the information on screens was taken from Eastman-Kodak publications.

32

By control of the shape of the reflecting sur-faces, the screen can reflect nearly all the lightfrom the projector evenly over a fan shaped area70 degrees wide and 20 degrees high. Manylenticular screens provide an image three orfour times as bright as a matte screen.

Beaded screens. Beaded screens are useful itlong narrow rooms or other locations where mostviewers are near the projector beam. They arewhite surfaces with imbedded or attached smallclear glass beads on silica chips. Most of thelight reaching the beads is reflected back to-wards its source. Thus, a beaded screen providesa very bright image for viewers seated near theprojector beam. As a viewer moves away fromthe beam, the image brightness decreases. Atabout 22 degrees from the projector beam, theimage brightness on a beaded screen will beabout the same as that on a matte screen. Be-yond this angle it will be less bright than on thematte screen. Students should sit no closer thantwo and one half times the image width from abeaded screen.

Rear - projection. Rear-projection pictureshave the same requirements for image brightness,size, and contrast as front-projected images. Rearprojector screens are made of glass, plexiglass,or flexible plastics with one side of the screen amatte surface.

To reduce space requirements in rear projec-tion, short focal length lenses sometimes areused. A single mirror between the projector andthe rear screen is necessary; however large mir-rors must be avoided. A special lens with a mir-ror encased and suitable for this purpose is avil-able from Buhl Optics.

With most projectors. images as wide as 42or 48 inches will be satisfactory on a dark rearprojection screen in moderately lighted rooms.For larger images, a light screen in a darkenedroom is usually needed. In very brightly lightedrooms, images should usually be no more than24 or 30 inches wide and the screen materialdark.

Front vs. Rear Projection. In consideringwhich projection system is best for given condi-tions, two common arguments regarding bothsystems are discussed below.

Shortened projection distances are claimedas an advantage by proponents of each system.While this is true in both cases, a short projec-tion distance often does not give the imagesharpness and brightness desired. However,when space is at a premium, short projectiondistances may be necessary and the equipmentcan be made to perform adequately.

Visibility in lighted areas also is claimed as anadvantage by proponents of both front and rearprojection. Either system will do a good job,depending upcn conditions. When a small image( up to 3 feet wide) is desired, a dark coloredrear-projection screen may provide dramaticallybetter image contrast and color saturation thana front-projection screen. Although a rear-pro-jection screen reduces image brightness, theamount of room light reflected toward the audi-ence is reduced by an even greater factor. Theback of the screen must be shielded from straylight. Front-projection screens always must beshielded from direct light.

When a large image ( wider than 3 feet) isdesirable, front-projection systems using a lenti-cular screen usually give better results thanrear-screen systems. Location and control ofroom lights are important factors to considerhere. In any case, more care must be given tothe orientation of the projector, screen, and au-dience than is necessary for a smaller rear-pro-jected image.

Screen Size. This should be such that theback row of viewers is no more than six times theimage width ( W ) from the screen, with thefollowing exceptions:

a. Certain materials, including many teachingfilms, are designed with titles and import-ant picture elements bold enough to permitsatisfactory viewing at distances of 8 to 10times the image width. When this is truefor the materials to be projected, the pro-jector may be moved closer to the screento give a smaller and brighter image. Mov-ing the projector enough closer to changethe back row from 6W to 8W will approxi-mately double the image brightness and al-low the front row to be moved a littlenearer the screen.

VC1111U.0141**"."."

33

=1,

b. In some situations, materials which limitmaximum viewing distance to less than 6Ware commonly used. Typewritten materialprojected with an overhead projector is anexample. For showing the full area of an8.5 by 11-inch page, pica type calls for amaximum viewing distance of 3W. Theteacher should critically test this for hisparticular situation, perhaps by taking thepoorest seat in the classroom.

A discussion of screen size with excellent solu-tions to common puzzles is available in EastmanKodak publication Effective Slides S-22, andLegibility Standards for Projected Material, S-4,and in the ACS publication, How to MakeSlides.

Image brightness. Required brightness ( theamount of light the student sees) depends onviewing angle; screen type; projector design,wattage, life rating, and age of lamp; characterof material being projected; image size; linevoltage; as well as on the design and cleannessof the optics. Lamp wattage alone gives littleindication of image brightness. Using wattageas a measure of image brightness is comparableto rating an engine by the fuel consumed ratherthan the work done.

The effectiveness of a projector, expressed asimage brightness, is defined in terms of lumenoutput. Lumen output divided by image area ( insquare feet) gives the foot-candles falling on the

screen from the projector. Foot-candles of illum-ination multiplied by the reflectance of the screen( about 0.85 for a good matte screen) gives infoot-lamberts, a measure of the brightness of theimage seen by the viewer.

Thus, a projector with a 120-lumen outputprovides 10-foot-candles of illumination for a3 by 4-foot ( 12 square foot) screen image; thatis, 8.5 foot lamberts of image brightness for theviewer of a good matte screen. With a projectorlight output of 80 - 100 lumens, and a mattescreen in a well-darkened room, an image 3 or4 feet wide can be viewed easily. As a roughestimate of the image brightness required, thereshould be as many foot lamberts of light persquare foot of screen as there are foot candles of

light in the room. For a more detailed discussionof image brightness see Eastman-Kodak publica-tion S-14 "What Can You Do With 100Lumens?"

Projector location. Optimum projector loca-tions depend upon a variety of factors includingthe lens and the screen size. Most manufacturersof projectors as well as lens suppliers ( Buhl Op-tical Company) can provide a wide range oflenses for any type of projector. To decide onthe lens needed for a given projector and situa-tion, one should first determine the size of thescreen to be used and then with the aid of atable such as Table F-9, the correct focal lengthfor the lens can be calculated.

TABLE F-9

D e t e r m i n i n g P r e j e c t i o n D i d :i n c e , Image Widt lio'or Letts

, 4 i. 1

tirMinethe 'projection distance a desired image width (orthe imaleWidth for e desired

*On-distance), lisitin the follOwing table the factor that apptieS to the fl m farina 'and teni, tau '*re

1;i0singiTnen ion a 'Oraightedge Minthe nomograph"so that the edge *Sit through the, :1 ithi Iftgure at. the a where the oU A other

,.,. ... , , ., ,

Ltittlie len,

, rgillitle desired OroleitOOn'7- ,

41

1MS I length; position the straightedge so that it Pass through the desOW that ja .0 t

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16mm MotionPictures(0.284" x 0.38"projector mask)

4.t.Ls

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2 x 2" Slides(38mm square or20-2,A381001,ri Oliaik)

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;1 (28mm)Zoom

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5.2,

3.7 6.02 x 2" Slides(26.5mm square L.-

mask)(KODAKINSTAMATIC)

2,9'''s4 3.8

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6 .8 - 5.7

enitn MotionPictures(0.129" x0472"projector mask)

. h A

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(15 - 25mm)

4A5.0

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illmstrip(172 x 23.00m)projected area)

3457

3.34A5.57 .7

Lantern SlidesMask( opening

3" wide)

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WidthOnehm)

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44

s;

FIGURE CI-1Computer assisted instruction permits many of the student-

teacher interactions which presently occur on an individual

basis (a) to be captured (b) and expanded for a multitudeof students (c).

iob

COMPUTER ASSISTED INSTRUCTION

Generally, the modern high-speed computeris considered to be an instrument used primarilyin the solution of complex numerical problemsor the processing of large quantities of data instandard ways. There have been many reportsof the use of both digital and analog computersin chemical education. However, it is also pos-sible to use computers to supplement teachingtechniques. This report concerns itself primarilywith these "non-classical" uses of the computer.

Computer assisted instruction ( CAI) can bedefined as a Socratic dialogue between a studentand his teacher with a computer as an inter-mediary ( Figure CI-1) . In essence, the com-puter serves as a medium to capture the way ateacher approaches his subject. His particularpoint of view, his bias, as well as the pedagogi-cal nuances he normally employs in teaching hissubject, all these can be stored in the computerto be explored at will by one or by a hundredstudents.EQUIPMENT

Basically, the computers used in CAI are veryfast data retrieval systems which include ( Fig-ure CI-2 ), ( a ) a central data processing unit,(b) large capacity data storage units, ( c ) atransmission control ( oi traffic regulator) unit,( d ) other peripheral devices which may be as-sociated with the system but which need not bediscussed at this point. The CAI system is de-signed to receive a set of sequenced instructionsand perform them automatically. These instruc-tions can be given to the system by either atypewriter communication unit or by standardpunch cards. The former method is usually usedby authors intially composing programs.

That part of the dialogue supplied by thecomputer is not limited to single words typedby a typewriter terminal under the "control" ofthe computer, although this is currently the pre-dominant mode of presentation. It also may con-sist of slides or motion picture film illustratingthe results of a laboratory investigation, an ex-cerpt from a book, or any other material, re-stricted only by the imagination of the teacherwho prepared the program and the capabilityof the hardware available to him ( Figure CI-3).

Indeed, it is even possible to provide an audiostatement by the computer, if required.

Since a computer is capable of making a seriesof decisions and initiating actions based on thesedecisions very rapidly, it is possible for a singledata processing unit to handle more than onestudent terminal at once. At present, up to 32students can interact simultaneously with onecomputer. The number of students is limited bythe sophistication of the computer in which theprogram is stored. The capability of a given in-stallation is not totally reflected by the numberof time-shared terminals, since the latter can bescheduled for student use at any hour of theday. In addition, computer terminals need notall be placed in one location but may be situatedin various convenient locations._

Student responses in the dialogue are not nec-essarily restricted to fixed phaseology since thecomputer can be instructed to search for keywords in the students' portion of the dialogue.Mechanically, student responses may be eithertyped on a typewriter-communication ,snit, orthe student can communicate with the computerby means of a light pen pointed at a specified por-tion of a cathode-ray tube.

InformationStorageUnits

Card Reader

Data ProcessingSystem

TransmissionControlUnit

Multiple Communication Unit

_L_

FIGURE CI.2A conceptual diagram of the basic units which make up a

typical CAI system.

37

1.

I

FIGURE CI.3A typical communications terminal for a CAI system. Thecomputer can present information or questions to the stu-dent by means of a printed output or by visual displays(either on a cathode ray tube or with a slide projector) whilethe student may respond to the computer with a typewriter

or a light pen.

In summary, the author of CAI material typeshis program into the computer, specifying infor-mation, questions, anticipated correct or wronganswers, and actions to be taken by the com-puter for a given student response. The programis constructed using standard operation codes.The computer stores the program and performsthe operations designated when the student in-teracts with the CAI system. It is also possiblefor the system to provide a record of studentresponses which can be used by the author inrefining the program.

At present, only the International BusinessMachines Corporation offers completely inte-grated CAI systems ( 1,2 ); however severalspecially designed installations exist which con-sist of central data processing units and associ-ated equipment manufactured by a variety ofcompanies (3). All of the major computer man-ufacturers are in the process of developing CAIsystems. Persons interested in exploring thepossibility of incorporating CAI techniques intotheir teaching should contact representatives ofthe firms that service the data processing equip-ment already available at their institutions, be-cause of the very fluid situation which exists inthe design and production of CAI systems. Also,it probably would be advisable to rent CAI

38

equipment rather than to purchase it outrightsince all of the units in a system are constantlybeing improved. For those persons interestedin a more modest approach to CAI techniques,terminals connected to computers located asmuch as several hundred miles away can berented.

PROGRAMSThe construction of a program for CAI is not

difficult for a skilled, experienced teacher,though it is time consuming and has some tedi-ous aspects. The techniques needed often aresimilar to those used in writing programmed in-struction ( 4 ).

In essence, a program is prepared by con-structing an imaginary conversation in the formof a flow chart ( Figure CI-4) between a studentand a teacher. The teacher must be continuouslyaware of exactly what he intends the student tolearn in detail and of the guiding statements hewould make to help a student whose responsessuggest a misunderstanding. In the constructionprocess, the teacher should assume that typicalstudents will deviate from the flow of the sub-ject in a variety of ways. The teacher, therefore,must compose a variety of corrective comments.Often these consist of a short dialogue with thestudent within the overall major dialogue. Whilethe dialogue is being composed, code-word andformat instructions to the computer are added.For example, the function "wa" in the Course-writer language ( 5) specifies that the next fol-lowing sequence of words is an anticipatedwrong answer to a preceding question. Thisfunction causes the computer to compare thestudent's response to the question with thewords which follow the symbol. If a match be-tween the student response and the author'sstatement is obtained, the computer is directedto make an appropriate statement ( or actione.g. change a slide ). If no match is obtained, adifferent action is initiated.

Programs are entered into the computer bythe author at a typewriter terminal. After suit-able preliminary planning [such as constructinga flow chart ( Figure CI-4 )], it is most efficientto construct the program at the terminal fromnotes. Once the program is constructed, inser-

tions, deletions or modifications of almost anykind also can be incorporated into the programfrom the typewriter terminal. ( See Reference 1,2, and 3 for details concerning terminal config-urations.) This procedure usually is necessarysince the teacher's imagination and experienceoften are not sufficiently percipient to encom-pass all but the more common misinterpretationsand outright errors a student will make when heis confronted by the program. Using a terminalin this way, the author can switch to "student"mode at will, testing out the logic and responsesincorporated in the program as it is written.Several published examples of CAI programsare available (6).

The validity of CA/ as a useful tool in teach-ing is perhaps best illustrated by an example.The flow chart in Figurt CI-4 illustrates the ap-plication of CAI to a chemical topic. This chartshows a portion of the logic for a program whichis to be used with laboratory work on colligativeproperties. The computer responses are givenin the boxes with rounded corners and the stu-dent responses in the squared boxes. Inspectionof this flow chart shows that a variety of path-ways al e available to the student as he proceedsthrough the program. It must be stressed thatno attempt has been made in this flow chart toprovide for equivalent or key word responses.

It should be noted that the statements ( Fig-

ure CI -4) from the computer match the preced-ing responses of the student. In the constructionof a program, it is necessary, in principle, toanticipate every possible response a studentmight make and to instruct the computer to pre-sent suitable statements ( as determined by theteacher-program author) to any response madeby an individual student. In practice, of course,this is impossible. Thus, in preparing a program,the teacher does the best he can to predict theseveral probable student responses to each state-ment in the program, ;ALA provides the corres-ponding statements which should be made toeach response. In these cases, one is not con-cerned with the phrasing of the students' re-sponses, but only with key words in the responsewhich the computer identifies as the clue to thenext statement that should be presented to thestudent.

Not all of the probable responses need bepredicted, since the development of a goodworking program usually involves refinementsbased on student use. Even a typical student re-sponse can then be accounted for in construct-ing a generalized computer statement to followthe response. Further, it appears in most cases,that though the phraseology, or style, of studentresponse varies, students tend to use a reason-ably small number of different, usually synony-mous, key words. Hence, with experience in thepreparation of instructional programs, the diffi-culty in anticipating student response becomeslessened.

Since the only readily available language (5)for CAI programs does not commit the teacherto any particular teaching method, it is possibleto incorporate a variety of teaching techniquespermitting him to retain originality in his pres-entation. Thus the success of the program islimI ed by the ingenuity of the instructor. Pro-grams can be written that essentially representdata retrieval systems in the worst sense of theword, i.e. a series of questions is asked by thecomputer and answered by the student with lit-tle interrelationships among successive ques-tions and answers. Alternatively, the programcan reflect a rich dialogue between a sensitiveteacher and an inquiring student with the com-puter merely acting as an intermediary. It seemsevident that program authors should also becompetent, experienced, modern chemistryteachers, or at least such individuals should beassociated with the deveolpment of chemistryprograms in CAI. Although CAI systems havenot yet received wide acceptance in chemistry,those anticipating t1-.e use of CAI techniquesshould exercise caution in purchasing commer-cially prepared CAI programs and should assurethemselves that the contents represent modernchemistry standards by requesting to see flowcharts of the programs before hand.

Computer-assisted instruction can be adaptedto the aptitude of the student in an almost hu-man way. For example, if the student repeatedlymakes a wrong selection of possible answers, thecomputer statements could be made kind andpatient at first but after several such responses,more stern comments or suggestions for more

39

The student has finished a laboratory experiment on colligativeproperties of solutions; in particular he has performed an ex-periment on the freezing point of a solution of acetic acid inWane.

Well, now that you have completed the experimental work oncolligative properties in the laboratory, perhaps we can discuss

your results. In considering the use of colligative properties suchas the freezing point depression of a solution to determine themolecular weight of a solute, what factors affect the freezing

point of a solution?

The amount of solute The amount of solvent

The amount of solvent The amount of solute

The concentration of solution(or)

The concentration of solute

(Any other response)

IWhat concentration units are usuallyused when discussing colligativeproperties?

Since we are dealingwith solutions, it mightbe well to consider var-iables that can bemeasured. Try again.

Fine, how are these two factors related?

Good, therefore the colligative prop-erties ore dependent upon the con-centration of the solution. What con-centration units are usually usedwhen discussing colligative proper-ties?

Correct. The freezing pointdepression of a solution isrelated to the molality of thesolution. Using the value of5.0 for the freezing point de-pression constant for ben-zene, calculate the molecularweight of acetic acid fromyour data and enter youranswer.

Remember, the molality is deter-mined from the volume solventwhich is a function of tempera-ture. Considering this effect whatconcentration unit would be moreappropriate for our purposes?

(any other answer)

any other number) (a number between 55.65) (a number between 115-125)

There appears to be anerror in your calcula-tions or in the way youcollected your data.Check these twopoints. If the resultsare the same pleasesign off and see yourinstructor, if not, enteryour recalculated an-swer.

Your molecular weightappears to be too lowfor your experimentaldata. Please recalculate.

The molecular weight appears tobe compatible with the data, how-ever it does not appear to supportthe usual formulation of aceticacid, i.e., CH3CO2H. Give an ex-planation for this discrepancy.

You are apparent,- havingdifficulty with concentra-tion units. Study the sec-tion on concentration unitsand on colligative proper-ties in your text before youproceed with your experi-ment. Please sign off.

Exit to a discussion ofthe hydrogen bond.

FMK C14of a flow chart for a program on colligative properties and hydrogen bonding. Many of the MOM Iftyphrimit for

,latiahroleat Stadent rigors" and key responses have been omitted for ,,Oreeeld,ofttdOehod Hof( -

intense study of the topic could be programmedinto the computer. Conversely, if the studentdoes well, the statements of commendation canvary, at one time calling the student by his lastname, but with a compliment attached, and onanother occasion with a short complement andthe student's first name. There is evidence tosuggest that some CAI programs have failed toteach well because the teacher-program authorshave used stilted, formal phrases in the state-ments they prepare for the computer to storeand present to the student. A computer can doonly what it is told to dol Hence, the statmentsgenerated by the computer for the student can,and perhaps should, have a personal quality inmany instances. Similarly, trite responses shouldbe avoided as they are not in the normal stu-den -teacher interaction.

THE USE OF CM IN CHEMISTRYIn some of the literature on the subject, it has

been suggested that CAI can, and will soon,replace or minimize the independent utilizationof many of the more familiar teaching tools.Other opinions dispute such claims, and supportthe contention that CAI can eventually becomeanother important and versatile tool a viewsupported by this report. The following briefdescriptions of different possible uses of CAI( only a few of which have as yet been even ten-tatively explored) will indicate some of theways in which this technique might prove usefulin chemical education.Laboratory. In the laboratory portion of acourse, students are usually expected to acquiresome manipulative technique as well as a facilityfor handling experimental data. Thus, a tech-nique may be taught in the laboratory ( e.g.,titration) and then the technique may be be-labored endlessly to show the student how itmay be used to obtain experimental results di-rected to a variety of ends. For example, it isnot uncommon to have students do acid-basetitrations, equivalent weight titrations, oxida-tion-reduction titrations, etc. However, all theseexperiments involve a basic titration techniqueand the student usually spends more than a fewafternoons doing essentially the same thing,each time for a slightly different reason. While

some repetition of technique is essential, over-exposure may detract from the learning of datahandling and the understanding of principles.To minimize this, CAI methods can be em-ployed to provide ( a) supplement laboratoryexperiments to give him experience in manipu-lating laboratory data or ( b ) simulate labora-tory experience before the student enters thelaboratory. Each of these represent legitimateuses of CAI when properly applied.

For example, the student can be assigned toconduct a trial titration at the computer ter-minal either before or after he has had labora-tory experience. In this instance, the computermay ask the student to decide upon the prepara-tion of a primary standard ( or, it can just asreadily ask the student to identify the first stepof the titration instead of naming it for him ).The student then selects a primary standard,and the approximate amount of the substance tobe titrated, whereupon the computer gives thestudent the precise weight of the sample. Next,the students decides to use, say a 100m1 volu-metric flask, and the computer responds by in-dicating that the quantity of sample weighedwill not dissolve completely in this amount ofsolvent, whereupon the student will either haveto decrease the sample size or increase the sizeof the flask. Afier more of this kind of dialogue,eventually the student simulates the preparationof his solution and arrives at the details of thetitration. At this time, utilizing pertinent dataand a generalized program ( which would notnecessarily be prepared by a teacher-programauthor, but would be available to him as a sub-routine by calling for it with a code word in aFortran-like computer language ), the computerwould calculate the pH of the solution for eachincrement of titrant added by the student. Thedata thus provided could be used to plot a titra-tion curve and to calculate the concentration oftitrant.

It is possible to write a program that incorpor-ates the experimental error expected for theequipment normally used in this type of experi-ment. In this case, a second or third computer-generated titration curve using the same samplewould give a similar but not identical answer!

41

In further dialogue, the student could now electto use his simulated standardized solution in anappropriate way. For example, a simulated un-known acid could be computer-titrated with thestandard solution and the pH of the unknownobtained from the computer for each incrementof titrant. The student would then be asked toplot his data and calculate the equivalent weightof the acid. Another sub-routine could simulatea deterioration of a standard solution, if thiswere chemically realistic and desired by theteacher-program author. The limitations of thistype of application is by no means restricted totitrations, but rather reside in the limits of theimagination of those who participate in thepreparation of programs for CAI in chemistry.

A different kind of laboratory simulation in-corporating visual presentation controlled by thecomputer is applicable to qualitative analysis(7 ). In this instance, the student sees on ascreen a picture of an unknown solution in abeaker, or perhaps in a test tube. After a dia-logue with the computer which terminates inthe student's deciding which, and how much,reagent to add, the next picture shows the re-sults of the addition. Then the student mightselect a separation of a precipitate and a decant-ate, say by filtration, and after telling this to thecomputer, the corresponding slide appears andshows the results. Obviously this mode of in-struction would require the preparation of theslides in advance. Currently, a maximum of 1000slides can be stored in a random access projec-tor and their rapid display controlled by thecomputer.

Tutorial assistance. CAI provides an ideal me-dium for the presentation of tvtorial, drill, orremedial material in subjects Ihere the onus in

the teacher-student relationship rapidly shiftsfrom the instructor teaching to the student learn-ing. Stoichiometry, balancing equations, andformula writing represent a few of the more ob-vious subjects for initial CAI programs in gen-eral chemistry. It is not possible, as has beensuggested above, for a teacher-program authorto predict all of the possible key words and sy-nonyms that might appear in the rerponses of alarge number of students. Although it is possible

42

to insert amendments to correct such deficien-cies as they occur, it may not always be neces-sary or desirable to do so. That is, at some pointsin a dialogue, with the computer, the studentmay reach an impass, i.e., a point where nostatements in the computer are suitable for hisresponse. In such a case, the next computerstatement can advise the student to see histeacher personally and even set up an appoint-ment for him ). The computer could even advisethe teacher that this particular student has un-derstood a topic up to a point, briefly describethe point giving difficulty, and describe the nextpoint to be covered after the difficulty is elim-inated. With this type of information, theteacher can, with less time involved, help thestudent over the hurdle personally, and sendhim back to the student terminal for furtherdialogue :here.Evaluation of student ability and progress.While the student is at a terminal, responding tothe statements he receives from the computer, arecord of individual student responses in sum-mary form can be maintained by the computerfor the teacher. Later, when using another pro-gram, the computer can readily indicate to theteacher that a student has, or has not, demon-strated an improvement in his proficiency in hisstudies as measured by a change in responses toperceptive answers to the computer statements.

It has been proved to be possible to generateindividualized quizzes on subjects that lendthemselves to this technique. Thus, with CAIequipment it is possible to construct a s . ofexaminations on which the student must rear h

a specified level. These examinations would 7 ieavailable on demand when the student feels hehas mastered the material. The computer pro-gram can generate the examination, grade it,inform the student of the results, and keep arecord of the grade.Incorporation of other material. It should beclearly understood that few students can toler-ate long sessions at a computer terminal, eventhough the statements presented by the com-puter may be lively and provocative on occa-sion. For this and other reasons, it is desirable torequire students to seek help periodically from

more familiar sources. Thus, at an appropriatepoint in the program the computer statementcould ask the student to leave the terminal andseek information from his text, a reference in thelibrary, or a brief experimental investigation,querying him about his findings upon his return.Students who are unable to indicate satisfactor-ily that they obtained the needed informationcan be given alternate, easier, assignments ( andthis fact noted in the record) or they can beasked to repeat the assignment. Any optionwhich is elected by the teacher-program authorand incorporated into the program can be em-ployed.

The CAI technique can easily require the stu-dent to read and study appropriate material be-

fore he uses the computer. For example, after aperiod of study on a given topic, the initial com-

puter interaction could be a short examination.Based on the result of this examination, the com-

puter could then further instruct the student inonly those matters for which his answers were

,.) unsatisfactory. Completing this, the computerand the student could proceed to a dialoguewhich develops the topic to the depth desired.

.1.110141MIN.

liwrimmow.

SUMMARYWith the experience available now, it is evi-

dent that CAI techniques can be applied toteaching a variety of topics in chemistry oftenmore efficiently than conventional methods.More importantly, the careful application ofCAI allows each student to proceed throughthe subject at his own rate, reworking the ma-terial as often as he feels is necessary. CAI mayfree the instructor to teach topics that are moredifficult to handle or those that may have beenomitted for lack of time. Although some mightbe concerned that CAI methods involve the de-humanization of teaching, it can be argued tothe contrary that these techniques provide amethod for more individualized instruction, away of capturing the individuality of a teacherand preserving it for all students.

It is apparent that CAI can be more useful tothose teachers in chemistry who have computersat their disposal if a method could be devisedfor the efficient exchange of programs. To helpcatalyze this exchange, it is suggested that per-sons interested in exchanging ideas on CAI doso through J. J. Lagowski, Department of Chem-istry, The University of Texas, Austin, Texas78712.

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REFERENCES AND FOOTNOTES ON COMPUTER ASSISTED INSTRUCTION

1. International Business Machines Corporation,"1500 Operating System, Computer-Assisted In-struction, Coursewriter II, System Summary," WhitePlains, New York, 1966.

2. For a description of IBM CAI systems see, (a)G. J. Rath, N. S. Anderson, and R. C. Brainerd, "TheIBM Research Center Teaching Machine Project,"Automatic Teaching: The State of the Art, (E. Calan-der, Ed.) New York, John Wiley and Sons, Inc., 1959;(b) R. P. Kropp, D. L. Hartford, H. W. Stoker, "Quar-terly Progress Report," Institute of Human Learn-ing, Florida State University, Tallahasee, Florida,October 1, 1965, December 31, 1965; (c) H. Mitzeland K. H. Wodtke, "The Development and Presenta-tion of Four Different College Courses by ComputerTeleprocessing," CAI Laboratory Interim Report,Pennsylvania State University, University Park,Pennsylvania, 1965: (d) V. Bunderson, "The TexasCAI Newsletter No. 1." The University of Texas, Aus-tin, Texas, February 15, 1966; (e) F. M. Tonge,Computers and Universities, Irvine CAI System; AWorkshop Conference, Newport Eeach, California,November 8-12, 1965.

3. For a description of existing CAI systems see,ft. example, (a) L. M. Stolurow and D. Davis,"Teaching Machines and Computer Based Sys-tems," Teaching Machines and Programmed Learn-ing, II. (Robert Glaser, Ed.) Washington, D.C., Na-tional Education Association of the United States,

1965; (b) Q. Zinn, "Computer Assistance for In-

struction Automated Education Letter, 1, 4 (1965);(c) R. J. Gentile, "First Generation of Computer-Assisted Instructional Systems: An Evaluation Re-view." Pennsylvania State University Computer As-

sisted Instruction Laboratory, University Park,Pennsylvania, 1965; (d) D. D. Bushnell, "Computcr-Based Teaching Machines," Journal of EducationalResearch, 55, 528 (1962); (e) D. L. Bitzer, P.Braunfield, and W. Lichtenberger, Plato II: A Multi-ple-Student, Computer Controlled Automatic Teach-ing Device," Programmer Learning and Computer-Based Instruction, (J. E. Coulson, Ed.) New York,John Wiley and Sons, Inc. 1962; (f) L. M. Stolurow,"Socrates: System for Organizing Content to Reviewand Teach Educational Subjects," Seventeenth An-

44

nual Industrial Engineering Institute Proceedings,University of California, 1965; (g) J. A. Swets, S. H.

Millman, W. E. Fletcher, and D. M. Green, "Learningto Identify Nonverbal Sounds: An Application of aComputer as a Teaching Machine," Journal of theAccoustical Society of America, 34, 928 (1962).

4. See for example, J. Young, J. Chem Educ., 40,

11 (1963); !bid, 400 (1963) and references therein

5. Coursewriter is a language developed for Inter-national Business Machines Corporation CAI sys-tems; see (a) A. Maher, "Computer Based Instruc-tion (CBI): Introduction to the IBM Project, "IBMResearch Report RC1114, White Plains, New York,1964, and Ref. 1. For other languages see (b) D. L.Bitzer, E. R. Lyman and J. A. Easley, Jr., "The Uses

of Plato; A Computer-Controlled Teaching System,"Report R-268, University of Illinois Coordinated Sci-

ence Laboratory, Urbana, Illinois, 1965; (c) J. Mc-Carthy, P. W. Abrahams, D. J. Edwards, T. P. Hart,and M. I. Levin, "LISP 1.5 Programmers Manual,"The Computation Center and Research Laboratory

of Electror.fr:s, Massachusetts Institute of Technol-ogy, Cambridge, Massachusetts, February, 1965;(d) J. G. Kemeny and T. E. Kurtz, "Basic," Dart-mouth College Computation Center, Hanover, New

Hampshire, January 1, 1966; (e) S. Feingold, "AFlexible Language for Programming Computer/Human Interaction," Systems Development Corpor-

ation, Santa Monica, California, February 28, 1966;(f) L. M. Stolurow and H. T. Lippert, "AutomaticallyTranslating Heuristically Organized Routings:AUTHOR I," Technical Memorandum No. 21, Train-ing Research Laboratory University of Illinois, Ur-bann, Illinois, February 10, 1966.

6. See, for example, J. A. Swets and W. Feurizig,"Computer Aided Instruction," Science, 150, 572(1965).

7. The first of this type of program was preparedon the gorup I cations by R. S. Hirsch and B. Mon-creiff (56th National Meeting of the American Insti-tute of Chemical Engineers, San Francisco, Calif.,May, 1965), followed by a program on the groupIV cations (J. J. Lagowski and C. E. Rodreguiz,152nd Meeting of the American Chemical Society,

New York, September, 1966).