Evening star. [volume], March 03, 1935, Page 12, Image 82

About Evening star. [volume] (Washington, D.C.) 1854-1972

Image provided by: Library of Congress, Washington, DC

                
Toys of Science
* Çrown - Up Scientists Today ι/fre Inlaying" with Toy Trains,
Toy Bridges and Sven Toy Tfivers. But It Is Serious
VIay—From Their Toys They zJlre J^earning to
Build (Cheaper and Better ^Carvels of engineering
By George W. Gray
•
Children would call them to#», but they are the work
things oj scientists. 1. Δ tiny model oj the longest sus
pension span on earth — the George Washington Bridge.
2. Those little metal forms, heaped with tand, test the
strength Sff structural materials. 3. Turn the crank and
this apparatus gives ffou high tide or low — it's a miniature
Photomontage by Charte* Fhelp· Cuahing
model oj part oj the Cape Cod Canal. 4. Thit lookt like a
doll'β haute, but ift really an architect't model oj a email
home. S. Ninety-mile gale» whittle through this wind
tunnel at Mattachutettt "Tech"; a "toy" plane it being
tetted. 6. Thit doll-on-a-ttick it helping to eolve the
problem oj vibration, vitaI to tmooth-running machinery.
IN Washington, at the Department of
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
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.
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
not weigh more than live 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 Hashing 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
revpaled.
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 he
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 I)am
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 fora 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.
Arcnnecis 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.