Visual Examinations LYNE S. METCALFE
New York City of all types have played an important part F.~nILMSchemical education, and without doubt will serve on an even wider basis in the postwar period. In the first place, wartime programs have developed a wider selection of subjects of interest in chemistry, and the technique of their use has been greatly improved by industry and in the Armed Forces. In the past, many instructors in chemistry have been content merely to show slidefilms and motion pictures, taking it for anted that the information thus presented visually~would"stick." Instructors have long realized the importance of properly integrating visuals with other study mediums, including laboratory, lecture, and book study, and of devising a method of testing out the progress made as a result of the use of the screen by the average student. Many new techniques which work in this direction have been developed in the wartime programs and will, in due course, he made available to the instructor in chemistry. Recently a visual train in^ clinic, held in cooperation with the U. S. Coast Guard-ne of the largest users of the picture screens in the Armed Servi c e s a t the Jam Handy Eye School, Detroit, Michigan, devised and developed a simple method of testing the individual student's absorption of knowledge from the picture screen, and also the value of a particular subject itself. I t is a system which the Coast Guard is using widely in its various visual training programs. This system is based upon the principle that examinations based upon knowedge gleaned from the visual medium should be tied in more closely with the visual element itself. Many students are competent to absorb and remember what is seen, and apply the knowledge, though they might possibly not be able to prove it in an ordinary written examination. By this method, the instructor, using the regular lesson slidefilm of the "reading" or discussional type, makes a paste of lampblack and water, and with an ordinary small art brush blacks out-on the glossy side of the filmstrip-certain elements, which may be lettering, pictures or parts of pictures, concepts, or figures. With these eliiifiations, the slideiilm is again projected on the screen or wall, and the class is confronted
with the problem of furnishing, orally, the missing material. There are a number of advantages here: first, the value of the refresher process which again registers the visual material through discussion and study; second, a "yardstick" by which the instructor may determine how much information the class has retained; third, the efficacy of the particular subject may be subjected to a test a t the same time. After the visual exams, the instructor may easily eliminate the paste by the use of a damp cloth or a rub of the thumb. The popularity of the discussional type of slidefilm in chemical education is due, in large measure, to its flexibility in permitting and provoking discussion among students, and elaboration of processes, concepts, and procedures by the instructor, since the image may be held on the screen for the purpose, or the film may be run backwards to frames previously screened. It also tends to guide question and answer sessions while the illuminated material is before the eyes of the class.
