Encyclopedia of 20th-Century Technology
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Meanwhile, the gas turbine was installed as a power unit in ships, railroad engines, and automobiles, but in none of these uses did it proceed far beyond the experimental stage. The space age spawned important new materials and uncovered new uses for old materials. For example, a vast range of applications have been found for plastics that have been manufactured in many different forms with widely varied characteristics.
Glass fibre has been molded in rigid shapes to provide motorcar bodies and hulls for small ships. Carbon fibre has demonstrated remarkable properties that make it an alternative to metals for high-temperature turbine blades. Research on ceramics has produced materials resistant to high temperatures suitable for heat shields on spacecraft. The demand for iron and its alloys and for the nonferrous metals has remained high. The modern world has found extensive new uses for the latter: In most of these cases the development began before the 20th century, but the continuing increase in demand for these metals is affecting their prices in the world commodity markets.
Both old and new materials were used increasingly in the engineering industry, which was transformed since the end of World War II by the introduction of control engineering, automation, and computerized techniques. The vital piece of equipment has been the computer, especially the electronic digital computer , a 20th-century invention the theory of which was expounded by the English mathematician and inventor Charles Babbage in the s.
The essence of this machine is the use of electronic devices to record electric impulses coded in the very simple binary system, using only two symbols, but other devices such as punched cards and magnetic tape for storing and feeding information have been important supplementary features. By virtue of the very high speeds at which such equipment can operate, even the most complicated calculations can be performed in a very short space of time. The Mark I digital computer was at work at Harvard University in , and after the war the possibility of using it for a wide range of industrial, administrative, and scientific applications was quickly realized.
The early computers, however, were large and expensive machines, and their general application was delayed until the invention of the transistor revolutionized computer technology. The transistor is another of the key inventions of the space age. The product of research on the physics of solids, and particularly of those materials such as germanium and silicon known as semiconductors, the transistor was invented by John Bardeen , Walter H.
Brattain, and William B. It was discovered that crystals of semiconductors, which have the capacity to conduct electricity in some conditions and not in others, could be made to perform the functions of a thermionic valve but in the form of a device that was much smaller, more reliable, and more versatile. The result has been the replacement of the cumbersome, fragile, and heat-producing vacuum tubes by the small and strong transistor in a wide range of electronic equipment.
Most especially, this conversion has made possible the construction of much more powerful computers while making them more compact and less expensive. Indeed, so small can effective transistors be that they have made possible the new skills of miniaturization and microminiaturization, whereby complicated electronic circuits can be created on minute pieces of silicon or other semiconducting materials and incorporated in large numbers in computers.
The potential for adaptation and utilization of the computer seems so great that many commentators have likened it to the human brain, and there is no doubt that human analogies have been important in its development. In Japan, where computer and other electronics technology made giant strides since the s, fully computerized and automated factories were in operation by the mids, some of them employing complete workforces of robots in the manufacture of other robots. In the United States the chemical industry provides some of the most striking examples of fully automated, computer-controlled manufacture.
The characteristics of continuous production, in contrast to the batch production of most engineering establishments, lend themselves ideally to automatic control from a central computer monitoring the information fed back to it and making adjustments accordingly. Many large petrochemical plants producing fuel and raw materials for manufacturing industries are now run in this way, with the residual human function that of maintaining the machines and of providing the initial instructions.
The same sort of influences can be seen even in the old established chemical processes, although not to the same extent: In medicine and the life sciences the computer has provided a powerful tool of research and supervision. It is now possible to monitor complicated operations and treatment. Surgery made great advances in the space age; the introduction of transplant techniques attracted worldwide publicity and interest.
But perhaps of greater long-term significance is research in biology, with the aid of modern techniques and instruments, that began to unlock the mysteries of cell formation and reproduction through the self-replicating properties of the DNA molecules present in all living substances and thus to explore the nature of life itself.
Food production has been subject to technological innovation such as accelerated freeze-drying and irradiation as methods of preservation, as well as the increasing mechanization of farming throughout the world. The widespread use of new pesticides and herbicides in some cases reached the point of abuse, causing worldwide concern.
Despite such problems, farming was transformed in response to the demand for more food; scientific farming, with its careful breeding, controlled feeding, and mechanized handling, became commonplace. New food-producing techniques such as aquaculture and hydroponics , for farming the sea and seabed and for creating self-contained cycles of food production without soil, respectively, are being explored either to increase the world supply of food or to devise ways of sustaining closed communities such as may one day venture forth from the Earth on the adventure of interplanetary exploration.
One industry that has not been deeply influenced by new control-engineering techniques is construction, in which the nature of the tasks involved makes dependence on a large labour force still essential, whether it be in constructing a skyscraper, a new highway, or a tunnel.
Nevertheless, some important new techniques appeared since , notably the use of heavy earth-moving and excavating machines such as the bulldozer and the tower crane. The use of prefabricated parts according to a predetermined system of construction became widespread. In the construction of housing units, often in large blocks of apartments or flats, such systems are particularly relevant because they make for standardization and economy in plumbing, heating, and kitchen equipment.
The revolution in home equipment that began before World War II has continued apace since, with a proliferation of electrical equipment. Many of these changes were facilitated by improvements in transport and communications. Transport developments have for the most part continued those well established in the early 20th century. The automobile proceeded in its phenomenal growth in popularity, causing radical changes in many of the patterns of life, although the basic design of the motorcar has remained unchanged.
The airplane, benefiting from jet propulsion and a number of lesser technical advances, made spectacular gains at the expense of both the ocean liner and the railroad. However, the growing popularity of air transport brought problems of crowded airspace, noise, and airfield siting. World War II helped bring about a shift to air transport: The first generation of transatlantic airliners were the aircraft developed by war experience from the Douglas DC-3 and the pioneering types of the s incorporating all-metal construction with stressed skin, wing flaps and slots, retractable landing gear, and other advances.
The coming of the big jet-powered civil airliner in the s kept pace with the rising demand for air services but accentuated the social problems of air transport. The solution to these problems may lie partly in the development of vertical takeoff and landing techniques, a concept successfully pioneered by a British military aircraft , the Hawker Siddeley Harrier.
As with Britain in the Industrial Revolution , the technological vitality of the United States in the 20th century was demonstrated less by any particular innovations than by its ability to adopt new ideas from whatever source they come. English Choose a language for shopping. Research on Mars was conducted primarily through the U. The same sort of influences can be seen even in the old established chemical processes, although not to the same extent: In another electric furnace process, calcium carbide reacted with nitrogen to form calcium cyanamide, from which a useful synthetic resin could be made.
Longer-term solutions may be provided by the development of air-cushion vehicles derived from the Hovercraft , in use in the English Channel and elsewhere, and one of the outstanding technological innovations of the period since The central feature of this machine is a down-blast of air, which creates an air cushion on which the craft rides without direct contact with the sea or ground below it.
The remarkable versatility of the air-cushion machine is beyond doubt, but it has proved difficult to find very many transportation needs that it can fulfill better than any craft already available. Despite these difficulties, it seems likely that this type of vehicle will have an important future. It should be remembered, however, that all the machines mentioned so far, automobiles, airplanes, and Hovercraft, use oil fuels, and it is possible that the exhaustion of these will turn attention increasingly to alternative sources of power and particularly to electric traction electric railroads and autos , in which field there have been promising developments such as the linear-induction motor.
Supersonic flight, for nearly 30 years an exclusive capability of military and research aircraft, became a commercial reality in with the Soviet Tu cargo plane; the Concorde supersonic transport SST , built jointly by the British and French governments, entered regular passenger service early in In communications also, the dominant lines of development continue to be those that were established before or during World War II. In particular, the rapid growth of television services, with their immense influence as media of mass communication, was built on foundations laid in the s and s, while the universal adoption of radar on ships and airplanes followed the invention of a device to give early warning of aerial attack.
But in certain features the development of communications in the space age has produced important innovations. First, the transistor, so significant for computers and control engineering, made a large contribution to communications technology. Second, the establishment of space satellites, considered to be a remote theoretical possibility in the s, became part of the accepted technological scene in the s, and these have played a dramatic part in telephone and television communication as well as in relaying meteorological pictures and data.
Third, the development of magnetic tape as a means of recording sound and, more recently, vision provided a highly flexible and useful mode of communication.
Fourth, new printing techniques were developed. In phototypesetting, a photographic image is substituted for the conventional metal type. In xerography, a dry copying process, an ink powder is attracted to the image to be copied by static electricity and then fused by heating. Fifth, new optical devices such as zoom lenses increased the power of cameras and prompted corresponding improvements in the quality of film available to the cinema and television. Sixth, new physical techniques such as those that produced the laser light amplification by stimulated emission of radiation made available an immensely powerful means of communication over long distances, although these are still in their experimental stages.
The laser also acquired significance as an important addition to surgical techniques and as an instrument of space weaponry. The seventh and final communications innovation is the use of electromagnetic waves other than light to explore the structure of the universe by means of the radio telescope and its derivative, the X-ray telescope. This technique was pioneered after World War II and has since become a vital instrument of satellite control and space research.
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Military technology in the space age has been concerned with the radical restructuring of strategy caused by the invention of nuclear weapons and the means of delivering them by intercontinental ballistic missiles. Apart from these major features and the elaborate electronic systems intended to give an early warning of missile attack, military reorganization has emphasized high maneuverability through helicopter transport and a variety of armed vehicles. Such forces were deployed in wars in Korea and Vietnam, the latter of which also saw the widespread use of napalm bombs and chemical defoliants to remove the cover provided by dense forests.
World War II marked the end of the primacy of the heavily armoured battleship. Although the United States recommissioned several battleships in the s, the aircraft carrier became the principal capital ship in the navies of the world. Emphasis now is placed on electronic detection and the support of nuclear-powered submarines equipped with missiles carrying nuclear warheads.
The only major use of nuclear power since , other than generating large-scale electric energy, has been the propulsion of ships, particularly missile-carrying submarines capable of cruising underwater for extended periods. The rocket, which has played a crucial part in the revolution of military technology since the end of World War II, acquired a more constructive significance in the U. The first spectacular step was Sputnik 1, a sphere with an instrument package weighing pounds 83 kilograms , launched into space by the Soviets on Oct.
The feat precipitated the so-called space race, in which achievements followed each other in rapid succession. They may be conveniently grouped in four chronological although overlapping stages. The first stage emphasized increasing the thrust of rockets capable of putting satellites into orbit and on exploring the uses of satellites in communications, in weather observation, in monitoring military information, and in topographical and geological surveying.
The second stage was that of the manned space program. This began with the successful orbit of the Earth by the Soviet cosmonaut Yury Gagarin on April 12, , in the Vostok 1. A series of Soviet and U. The third stage of space exploration was the lunar program, beginning with approaches to the Moon and going on through automatic surveys of its surface to manned landings. Again, the first achievement was Soviet: Luna 1, launched on Jan. Luna 2 crashed on the Moon on Sept.
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The first soft landing on the Moon was made by Luna 9 on Feb. By this time excellent close-range photographs had been secured by the United States Rangers 7, 8, and 9, which crashed into the Moon in the second half of and the first part of ; and between and the series of five Lunar Orbiters photographed almost the entire surface of the Moon from a low orbit in a search for suitable landing places.
Meanwhile, the size and power of launching rockets climbed steadily, and by the late s the enormous Saturn V rocket, standing feet metres high and weighing 2, tons 2,, kilograms at lift-off, made possible the U. Apollo program, which climaxed on July 20, , when Neil Armstrong and Edwin Aldrin clambered out of the Lunar Module of their Apollo 11 spacecraft onto the surface of the Moon.
The manned lunar exploration thus begun continued with a widening range of experiments and achievements for a further five landings before the program was curtailed in The fourth stage of space exploration looked out beyond the Earth and the Moon to the possibilities of planetary exploration.
These findings were confirmed by the Soviet Venera 3, which crash-landed on the planet on March 1, , and by Venera 4, which made the first soft landing on Oct. Later probes of the Venera series gathered further atmospheric and surficial data.
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Research on Mars was conducted primarily through the U. Mariner and Viking probe series. During the late s, photographs from Mariner orbiters demonstrated a close visual resemblance between the surface of Mars and that of the Moon. In July and August , Vikings 1 and 2, respectively, made successful landings on the planet; experiments designed to detect the presence or remains of organic material on the Martian surface met with mechanical difficulty, but results were generally interpreted as negative.
Photographs taken during the early s by the U. In the mids the attention of the U. It was followed by the Challenger , which made its first mission in April Both vehicles were used to conduct myriad scientific experiments and to deploy satellites into orbit. The space program suffered a tremendous setback in when, at the outset of a Challenger mission, the shuttle exploded 73 seconds after liftoff, killing the crew of seven. The early s saw mixed results for NASA.
Interplanetary probes, to the delight of both professional and amateur stargazers, relayed beautiful, informative images of other planets. At the dawn of the space age it is possible to perceive only dimly its scope and possibilities. But it is relevant to observe that the history of technology has brought the world to a point in time at which humankind, equipped with unprecedented powers of self-destruction, stands on the threshold of extraterrestrial exploration.
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Please note that our editors may make some formatting changes or correct spelling or grammatical errors, and may also contact you if any clarifications are needed. The 20th century Technology from to Recent history is notoriously difficult to write, because of the mass of material and the problem of distinguishing the significant from the insignificant among events that have virtually the power of contemporary experience. Fuel and power There were no fundamental innovations in fuel and power before the breakthrough of , but there were several significant developments in techniques that had originated in the previous century.
Gas-turbine engine The principle of the gas turbine is that of compressing and burning air and fuel in a combustion chamber and using the exhaust jet from this process to provide the reaction that propels the engine forward. Petroleum As far as fuel is concerned, the gas turbine burns mainly the middle fractions kerosene, or paraffin of refined oil, but the general tendency of its widespread application was to increase still further the dependence of the industrialized nations on the producers of crude oil , which became a raw material of immense economic value and international political significance.
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