CHEMICAL EXEIBITS at A CENTURY of PROGRESS IRVING E. MUSKAT A Century of Pro.oress, Chicago, Illinois
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HERE is a natural tendency for the individual It is, therefore, fitting that the approach to the Hall of saentist to believe that the particular branch Science from the great plaza facing the lake should of science in which his interest lies is of basic present to the visitor some concept of the phenomenal importance in its contributions to human knowledge development of chemistry, as a symbol of the contribuand thereby to human progress. However, the chemist tion of science to human progress. The Century of Progress fortunately has been able to obtain a series can claim, with some justice, that in his field--chemistry--all sciences find their common meeting ground. of ten strikingly beautiful murals which depict the Thus the chemist uses mathematics as a tool for stating growth and development of chemistry and its applicamore accurately his chemical observations; he applies tion to industry, commerce, and medicine. These to his chemical problems the principles described by murals will be placed on the front of the Hall of Science. physics; he isolates, purifies, and makes available for facing the lake where they will sewe the dual purpose use the minerals and ores located by the geologist; of adding to the beauty of the building and introducing and he is now interpreting biological phenomena in the visitor to the exhibits that are displayed within. terms of chemical changes and is helping to pave the As one enters the Great Hall (shown above) of this way for a clearer understanding and thereby a more building which has been dedicated to Basic Sciences, accurate control over the physiological processes oc- the attention is a t once focused on an imposing model of curring in our own bodies. the periodic table of the chemical elements which oc387
surmounts the periodic table. On this globe will be indicated the location of the most important sources of the more common elements. The entire exhibit is so designed and so lighted that, despite its enormous size, every visitor may view a t close range any part of the display. Surrounding the Great Hall are presented the chemical exhibits, arranged in a series of connected stories, each story told by a number of dynamic exhibits displayed in a logical sequence. The guiding principle in the preparation of these chemical exhibits has been that the exhibits must be not only interesting, attractive, and entertaining to those who are merely curious, but also instructive to those who come to learn. In addition, the exhibits have been constructed in conformity with a scientific authenticity which will enable them to withstand the rigorous scrutiny of the trained scientist. They are not the usual trade-show or museum-type exhibit, but are dynamic models which show principles and processes rather than products and equipment. The preparation of chemical exhibits presents many problems which are different from those encountered in the preparation of other technical exhibits. It is interesting to note that there are museums throughout the world in which are displayed excellent exhibits in astronomy, geology, physics, biology, and medicine; but nowhere is there a really effective or adequate exhibit in chemistry. It is COURTOF T H E HALLOF SCIENCE. WITH ITS c . 4 ~ l l . L O N TOWER not difficult to find a reason for this. For incupies one end of the Hall. This exhibit, by virtue of stance, in the preparation of a dynamic exhibit in the fundamental scientific principle which i t depicts, by physics, a convenient source of electric current is the its central location, and by its unusually striking design, principal requirement. To show a chemical principle, has rightfully been called the central feature of the one must supply various forms of energy together with entire Exposition. The periodicity of the elements, chemical reagents which are used up and must be rewhich this model portrays, is one of the most funda- placed. Refuse and by-products must be removed. mental concepts of modern chemistry. This classifica- Fumes are produced and proper ventilation must be tion of the elements has made possible the prediction installed to remove corrosive or poisonous gases. of the probable sources and the ultimate discovery of Great care must be used to obviate the dangers of fire new elements; it enables the chemist to predict the and explosion. All of these and many other difficulties properties of new compounds; and it has pointed out must be surmounted before one can build a dynamic to the research worker new directions in which fruitful chemical exhibit. It is one thing to heat mercuric oxide in a test-tube and to show that mercury and results may be expected. This exhibit as a whole is approximately thirty feet oxygen are formed, but it is quite another thing to conhigh and twenty-five feet in diameter. The lower part struct a dynamic exhibit which will automatically consists of a beautifully designed model of a periodic perform this reaction without fail once a minute, ten table of the chemical elements, in which is displayed in hours a day, for one hundred fifty days. It is just this .proper sequence a sample of each of the elements. In type of exhibit which we proposed to develop and coneach case the most important source and the most im- struct and have to a large measure succeeded in acportant use of the elements are also presented. The ma- complishing. In presenting chemistry to the lay public-for you terial for this exhibit has been assembled from all over the w o r l d a n d in many instances very rare and beauti- must remember that these exhibits are prepared so that ful specimens have been obtained. To emphasize the they will be intelligible to the average man and wofact that the ninety-two chemical elements comprise all man-we have deviated from the usual methods of that we know of the earth, a ten-foot revolving globe teaching chemistry in subdivisions such as inorganic,
organic, physical, photochemistry, etc. Rather, chemistry is presented as the fundamental science of the transformation of matter and the laws which describe these transformations. We then show the methods and tools of chemistry and how, by means of these, the chemist has developed our natural resources and transformed them into the necessities of our daily life. The first unit in the chemical exhibits deals with chemical changes and the various ways in which they may be produced. Here, among others, may be seen such striking exhibits as the burning of iron, streams of liquid fire, metallic mercury produced from a clear solution, and fire started with water. These exhibits are spectacular, but since they are designed to illustrate definite types of chemical changes rather than to mystify the layman, an accurate explanation accompanies each one. The exhibits on chemical changes are followed by exhibits on catalysis, designed to show methods by which the speed of chemical reactions may be varied. The central feature of this unit is the story of sulfur. A dynamic display depicts in miniature the actual mining of sulfur, its conversion to sulfur dioxide, and finally, its transformation to sulfuric acid by the contact process. In the contact process is shown the Cottrell precipitator by means of which the finely divided, colloidally dispersed sulfuric acid is quickly changed from a fog to a heavy liquid. This leads directly into the story of colloids. The nnit on colloids presents to the visitor some of the interesting information which the chemist has gained from the study of this class of substances. In this unit one can see a beautiful demonstration of the Brownian movement. There are also exhibits on the preparation and precipitation of red and blue colloidal gold, the purification of water by the precipitation of colloidally suspended impurities, and a complete operating exhibit on ore flotation which shows the separation of gold, lead, and zinc concentrates from the crude ores: The fourth nnit deals with the chemical treatment and refining of oil. A complete miniature refinery, made largely of glass, has been constructed; and the refining processes, beginning with the fractional distillation of crude petroleum and ending with the highly purified products, may be seen in operation. A voice will describe and explain each step of the process. Demonstrations of some of the characteristic properties of oils will be included. The entire display is presented with the idea of showing the result of the application of theoretical knowledge to a practical problem. The fifth unit presents the transformation of rubber from the crude, milky latex to the finished product. In this exhibit one can see rubber latex flowing from a real rubber tree which has been brought here from Africa.
Dynamic exhibits will demonstrate the continuous coagulation of rubber with formic acid, the electrodeposition of rubber, and the process of vulcanization. The nature and use of accelerators, pigments, and antioxidants will also be shown. The story of air is introduced by means of a diorama of Lavoisier in his laboratory. In addition to exhibits illustrating the composition of air and the properties of its constituents, this unit contains other exhibits which show various methods for liquefying gases by cooling, by increasing the pressure, and by rapid expansion of the gas. In a lecture room on the ground floor of the Hall of Science the properties of liquid air will be continuously demonstrated, including some of the striking effects of the extremely low temperature which can be produced by means of liquid air. The unit on coal tar is designed to show how the chemist has developed a by-product-which manufacturers formerly paid to have removed as refuse--into some of the most valuable products of our present day. From coal tar are prepared our beautiful dyes, our medicinals, our perfumes, our explosives, and our plastics. The feature of this unit is an exhibit showing the processes involved in the manufacture of bakelite.
An outstanding feature of the section dealing with electrochemistry is a large, automatically operating exhibit which demonstrates the process of chromium
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moving picture projected from behind on his own front. The robot describes the constituents of foodthe proteins, carbohydrates, fats, vitamins, and minerals. He demonstrates the function of each and how they are broken down or digested in the body to simpler products which can then be assimilated by the body
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plating. The visitor will be presented with a chromium plated souvenir which he has seen pass through the plating process. Electric furnaces of the arc, resistance, and induction type, and some of the effects of the terrific heat which they generate will be shown. The final story is on the chemistry of food and nutrition. This exhibit is unique. A ten-foot robot will give a twenty-minute lecture on food chemistry and nutrition, illustrating his lecture by means of demonstrations which he operates, a number of static exhibits to which he points, and finally the demonstration of the processes of digestion on himself by means of a
tissues. He also describes the functions of the hormones in our bodies. In addition to these basic science exhibits a number of the chemical concerns are presenting striking exhibits showing their contribution to the industrial and commercial development of the scientific principles demonstrated in our basic science exhibits.
SECTION OF PHARMACY OP
THE SIXTEENTH
CENTURY.
BROUGHT PROM
GERMANY BY
E. R. SQUIBB & SONS AND
ro BE SHOWN FIRSTAT THE
CENTURY 08
PROGRESS
EXHIBITION AT CHICAGO
