The educational screen (c1922-c1956])

Page 70 The Educational Screen NEW FILMS OF THE MONTH As They Look to A Teacher Committee Conducted by L. C. LARSON Instructor in School of Education Consultant in Audio-Visual Aids Indiana University, Bloomington The Airplane Changes The World Map (Erpi Classroom Films Inc., 1841 Broadway. New York City) 11 minutes, 16mm. sound. Sale price $50.00 less 10% educational discount. Apply to producer for rental sources. Discussion guide available. As progressively closer views of a rotating globe are shown, the commentator states that distortion results when we at- tempt to transfer an impression gained from viewing a globe to two-dimensional charts or maps. Before 1492 flat maps were adequate, since most people thought of the earth as a giant flat object in space. After Magellan sailed around the earth, new navigational maps were made from globes designed by Behaim and Schoner. A major sequence is devoted to an explanation of latitude and longitude and the Mercator, Mallweide, and Goode pro- jections. The effects of different types of projection on the interpretation of size and distance are shown through the use of animation and illustration. The relationship between our concept of the earth and methods of transportation is emphasized in the last sequence. The concept of eastern and western hemispheres was developed at the time of sailing vessels when navigators wanted a map showing prevailing winds. With the development of steam, ships could take the shortest or great circle routes. With the development of the airplane which can disregard obstacles of botli land and water, the old navigational routes are again outmoded and air transportation uses the true great circle routes. Air and water distances between major cities in the world are com- pared through the use of routes outlined on a globe. Circles drawn with a 6.000 mile radius and with Tokyo. Central Europe, and Chicago as centers include most of the land area of the world. The commentator states that from these cen- ters the outer limit of each area can be reached by air within twenty-four hours. Committee Appkaisai. : In addition to demonstrating the changes in spatial relationship and traveling distances between points on the globe brought about by air transportation, this film also provides a good explanation of the usefulness and limitations of various flat map projections made from the globe. This film which is an excellent treatment of a difficult subject should be one of the most popular of recent Erpi re- leases since teachers of general science, geography, math- ematics, and related subjects will all find it of interest and value to their students. Rough Turning Between Centers (Castle t'llms. Inc., 30 Rockefeller Plaza, New York) 14 minutes, 16mm. sound. Sale price $12.94. Apply to dis- tributor for rental source. Visual Learning Guide for this and other U. S. Office of Education Training Films avail- able from National Audio-Visual Council, 160 North I.a- Salle Street, Chicago, Illinois. Beginning with the blue print of the desired part and a piece of raw stock cut to length and centered, this film details the operational steps in turning a pin to the rough diameter required for finishing. The three safety considera- tions of all machine operation are emphasized throughout the film in commentary and picture; how proper clothing, hair cut, and careful habits of movement born of respect for his machine protect the operator: how continuous checking and a rigidly maintained routine of operation protect the machine from damage; and how constant reference to the blue print. Assisted by LLOYD F. EVANS and CAROLYN GUSS Extension Division Indiana University, Bloomington frequent checks of tlie work in progress and correct manipula- tion of controls and tools avoid damage to the piece. The cleaning and oiling of all parts of the lathe and the insertion of the cleaned centers preparatory to setting up the work are shown. The measurements of the raw stock being checked, the centers lubricated, and the work locked in place in the lathe are then seen. Next, through animation and extreme closeups, the designing and grinding of a rough- ing tool are shown and it is seen being mounted in the proper position in the tool holder. Speed and feed having been set for the kind of material and the depth of cut, the lathe is cautiously turned by hand to make sure it is in safe operating adjustment before a quarter inch trial cut is made and the resulting true diameter measured with micrometer calipers. From this gross trued diameter, the desired net diameter is subtracted, the cutting tool set to cut one-half the diflfercnce and a short cut taken and checked with the micrometer cali- pers for the diameter called for in the blue print. .\ closeup in slow motion with extreme magnification shows the action of a well-designed cutting tool completing one-half the cut. The stock is reversed end the cut finished for the full length of the pin. the finished work is compared with the drawing to check the accuracy of the work, and it is found to be within the limits required by the following operation. Committee .Appraisal: This film, the fir.st in a Series on the "Operation of the Lathe," successfullly introduces the elementary operation of straight turning with a roughing tool. It uses effectively experience situations needed to provide a basis for both integrative and precision learning. The sequence showing the approval of the dimensions of the finished work compared with those of the drawing should contribute to the exercise of judgment needed by an operator in determining whether or not the completed dimensions of a given job are within the limits required by the next operation as shown by the drawing. On the other hand, an excellent example of precision learning is contained in the sequence which de- tails the grinding of the cutting edge and clearance angles on a tool bit for a given operation. With its technical accuracy and exceptionally competent photography, the film should be widely used in classes in machine tool operation. Balloons (Educational Film Institute, New York University, Wash- ington Square, New York City) 28 minutes, 16mm. sound. Sale price $60.00. .^pply to distributor for rental sources. Pro- duced by Department of Child Study, Vassar College. Marvin and Terry, two boys between the ages of four and five, are subjects in an experimental situation designed for the study of aggressive and destructive impulses. The introductory- title explains that because of difi^erent experiential backgrounds and personality patterns each child is unique. Assistants are shown preparing the experimental room while the commentator explains that the two boys will be introduced individually to the same situation for the purpose of observing their reactions. Marvin is brought into a room which contains balloons of various sizes, shapes, and colors. He is told that he might play Vvith them in any manner that he chooses. He immediately says that he hopes they don't break, and to an invitation to break them he replies in the negative. The psychologist asks Marvin if it would be all right if he broke a balloon, but Marvin says, "If you do, I'll go away." When the psychologist takes a small scrap of rubber from his pocket, forms a tiny balloon, and be- gins to twist it to break it, Marvin flinches and advises him not to break it. However, a smile of satisfaction flits across his