Evening Star Newspaper, March 3, 1935, Page 82

12 THIS WEEK [0YS of SCIENCE * Grown-Up Scientists Today Are «Playing” with Toy Trains, Toy Bridges and Even Toy Rivers. But It Is Serious Play — From Their Toys They Are Learning to Build Cheaper and Better Marvels of Engineering Children would call them toys, but they are the work- things of scientists. 1. A tiny model of the longest sus- pension span on earth — the George Washington Bridge. 2. These little metal Jorms, heaped with sand, test the strength af structural materials. 3. Turn the crank and “ thie apparatus gives you high tide or low — i¥’s a miniature Terrestrial Magnetism of the Carnegie | Institution, a man was shooting arrows into hot molten quartz. As an arrow cut through the plastic mass, it dragged some of the liquid into long streamers tapering into fine threads, which instantly solidified to the hardness characteristic of quartz. ‘‘That's how we get filaments fine enough for delicate detectors,” explained the scientist in charge of this archery. At the Westinghouse Laboratory, near Pittsburgh, a doctor of philosophy was “playing’’ with a toy train. A 12-year-old boy would have gone into whoops of ecstacy over that set-up, but the scientist worked very IN WASHINGTON, at the Department of By GEORGE W. GRAY Photomontage by Charles Phelps Cushing quietly, assembling the various parts into a streamlined sequence which he placed in a wind tunnel and tested under varying velo- cities of wind — to measure air resistance. Out of such experiments are emerging new designs of locomotives and cars for tomorrow’s age of speed. The idea is not new — it is only the applica- tion of this familiar engineering strategy to railway train design, to automobile design, and even to skyscraper design, that is novel. For a half century, shipbuilders have been guided by tests of models in towing tanks. For a quarter century, the wind tunnel and the small-scale model have been indispensable tools in the advancement of aeronautics. model of part of the Cape Cod Canal. 4. This looks like a doll’ s house, but i¥’s really an architect’s model of a small home. 5. Ninety-mile gales whistle through this wind tunnel at Massachusetts “Tech’; a‘“toy” plane is being tested. 6. This doll-on-a-stick is helping to solve the problem of vibration, vital to smooth-running machinery. During the depression, with its accelerating demand for economies, the practice has spread with lightning speed into many branches of engineering research; and today there is hardly an important project in any field of applied science that may not first be tested in the small, and worked out in essential details before being committed to the large. Sometimes the problem is not to facilitate motion, but rather the opposite. In New York, at the research laboratory of the Columbia School of Mines, I saw the model of a retaining wall. The model was carved out of trans- parent bakelite, and back of this toy wall was a load of sand to simulate the load of earth that will burden the real wall. The whole did March 3, 1935 not weigh more than five pounds — 1 held it in my hand — and it seemed over-optimistic to expect such a toy-like thing to tell anything important about the stresses which the hundred-times larger wall of concrete would be called on to endure. But the researchers have ways to get around the obvious. In this Columbia labor- atory is an ingenious whirling machine. It can multiply a load 3,000 times — that is, increase the ‘‘weight’ of a pound to a ton and a half! When the model was placed in this apparatus and whirled, centrifugal forces were generated which made the toy load of sand press against the toy wall with a force directly proportional to that of gravitation. A flashing light illu- minated the model for an instant at each revolution, enabling a fast camera to photo- graph the behavior of the wall under the strain — and the weak spots were glaringly revealed. It would be more direct, of course, to test the concrete wall itself, full size, under the natural conditions of its site. But this would cost thousands of dollars and months of time, and would eat up in advance any possible saving. The small model costs a few dollars only, it can be set up within a few hours, and by applying the mathematical law of simil- itude the critical facts about the wall can be learned as accurately from the toy as from the full-scale structure. As a result of this dis- covery, whole laboratories are given over to the fascinating pursuit of tinkering with marvelously exact scientific toys. At the government’'s Waterways Experi- ment Station on the Mississippi near Vicks- burg, for example, is a 140-acre tract on which every dangerous curve and contour of the Mississippi river has been worked out in miniature. Recently, as a result of these studies with a toy river, seven bends in the Mississippi were cut through, shortening the stream by seventy miles and simplifying the problem of flood control. Before the first concrete for Boulder Dam was poured, the whole project had been tried out in plaster models at the laboratory of the Bureau of Reclamation in Colorado. Mercury was used to simulate water in the miniature dam. Similar studies guided the Norris Dam engineering in the Tennessee Valley. A unique tower construction has been adopted for the San Francisco Bridge, now being built across the Golden Gate. This innovation was perfected through tests of steel models, performed at Princeton Univer- sity and at the University of California. The Port Authority of New York used brass as the material for a model of the span of its Bayonne Bridge; and by means of this model learned the economy of using a less expensive steel than had been thought necessary. At Cambridge, Mass., is a shaking platform geared to make motions like an earthquake. This jigger grew out of certain experiences in California in 1933, when a quake put many elevated water tanks out of use, seriously crippling fire protection. So a group of fire insurance companies began to ask questions. Are elevated tanks peculiarly vulnerable to earthquake shocks? What structural type will stand most securely? They turned to the Massachusetts Institute of Technology with these questions —and the answer is being sought from tank models on that shaking platform. Already these studies have demon- strated that some of the forms which have been designed to add strength to a structure are in reality sources of weakness under earth- quake conditions. Architects are using models to try out preliminary plans. When the new laboratory building of the Mellon Institute in Pittsburgh was projected a few years ago, a four-foot- high model of the proposed nine-story building was erected. Certain changes resulted, and then a nineteen-foot model showed the design in larger scale. Now a full-size model of a corner of the building, and full-size models of two typical laboratory rooms have been erected for detailed studies of arrangement, furniture and service features. Altogether $60,000 was spent on these models — but results justified it, say the engineers. One of the current ingenuities of the experts is to make the toy model out of glass, cellu- loid, bakelite, or some other transparent material. When a strain is applied under polarized light, beautiful patterns of rainbow bands show up at various areas, and by reading these rainbows the designer can tell where the part is weak and the degree of its strength. In a study of a certain dirigible air- ship, 3,000 parts of its structure were repro- duced in miniature in celluloid and tested under the polariscope. | | - . R