jueves, 11 de febrero de 2010

Ancient Civilization





It was the growth of the ancient civilizations which produced the greatest advances in technology and engineering, advances which stimulated other societies to adopt new ways of living and governance.

The Egyptians invented and used many simple machines, such as the ramp to aid construction processes. The Indus Valley Civilization, situated in a resource-rich area, is notable for its early application of city planning and sanitation technologies. Ancient India was also at the forefront of seafaring technology—a panel found at Mohenjodaro, depicts a sailing craft. Indian construction and architecture, called 'Vaastu Shastra', suggests a thorough understanding of materials engineering, hydrology, and sanitation.

The Chinese made many first-known discoveries and developments. Major technological contributions from China include early seismological detectors, matches, paper, cast iron, the iron plough, the multi-tube seed drill, the suspension bridge, the parachute, natural gas as fuel, the magnetic compass, the raised-relief map, the propeller, the crossbow, the South Pointing Chariot, and gun powder.


An illustration of the aeolipile, the earliest steam-powered deviceGreek and Hellenistic engineers invented many technologies and improved upon pre-existing technologies. Particularly the Hellenistic period saw a sharp rise in technological inventiveness, fostered by a climate of openness to new idea, royal patronage the blossom of a mechanistic philosophy and the establishment of the Library of Alexandria and its close association with the adjacent museion. In contrast to the typically anonymous inventor of earlier ages, ingenuine minds such as Archimedes, Philo of Byzantium, Heron and Ctesibius now remained known by name to posterity.

Ancient Greek innovations were particularly pronounced in mechanical technology, including the ground-breaking invention of the watermill which constituted the first human-devised motive force not to rely on muscle labour (besides the sail). Apart from their pioneer use of waterpower, Greek inventors were also the first to experiment with wind power (see Heron's windwheel) and even created the earliest steam engine (the aeolipile), opening up entirely new possibilities in harnessing natural forces whose full potential came only to be exploited in the industrial revolution. Of particular importance for the operation of mechanical devices became the newly devised right-angled gear and the screw.


The compartmented water-wheel, here its overshot version, was invented in Hellenistic timesAncient agriculture, as in any period prior to the modern age the primary mode of production and subsistence, and its irrigation methods were considerably advanced by the invention and widespread application of a number of previously unknown water-lifting devices, such as the vertical water-wheel, the compartmented wheel, the water turbine, Archimedes screw, the suction pump, the bucket-chain and pot-garland, the force pump, the suction pump, the double-action piston pump and quite possibly the chain pump.[2]

In music, water organ, invented by Ctesibius and subsequently improved, constituted the earliest instance of a keyboard instrument. In time-keeping, the introduction of the inflow clepsydra and its mechanization by the dial and pointer, the application of a feedback system and the escapement mechanism far superseded the earlier outflow clepsydra.

The famous Antikythera mechanism, a kind of analogous computer working with a differential gear, and the astrolabe show great refinement in the astronomical science.

Greek engineers were also the first to devise automaton such as vending machines, suspended ink pots, automatic washstands and doors, primarily as toys, which however featured many new useful mechanisms such as the cam and gimbals.

In other fields, ancient Greek inventions include the catapult and the gastraphetes crossbow in warfare, hollow bronze-casting in metallurgy, the dioptra for surveying, in infrastructure the lighthouse, central heating, the tunnel excavated from both ends by scientific calculations, the ship trackway, the dry dock and plumbing. In horizontal vertical and transport great progress resulted from the invention of the crane, the winch, the wheelbarrow and the odometer.

Further newly created techniques and items were spiral staircases, the chain drive, sliding calipers and showers.


Pont du Gard in France, a Roman aqueductThe Romans developed an intensive and sophisticated agriculture, expanded upon existing iron working technology, created laws providing for individual ownership, advanced stone masonry technology, advanced road-building (exceeded only in the 19th century), military engineering, civil engineering, spinning and weaving and several different machines like the Gallic reaper that helped to increase productivity in many sectors of the Roman economy. Roman engineers were the first to build monumental arches, amphitheatres, aqueducts, public baths, true arch bridges, harbours, reservoirs and dams, vaults and domes on a very large scale across their Empire. Notable Roman inventions include the book (Codex), glass blowing and concrete. Because Rome was located on a volcanic peninsula, with sand which contained suitable crystalline grains, the concrete which the Romans formulated was especially durable. Some of their buildings have lasted 2000 years, to the present day.

The engineering skills of the Inca and the Mayans were great, even by today's standards. An example is the use of pieces weighing in upwards of one ton in their stonework placed together so that not even a blade can fit in-between the cracks. The villages used irrigation canals and drainage systems, making agriculture very efficient. While some claim that the Incas were the first inventors of hydroponics, their agricultural technology was still soil based, if advanced. Though the Maya civilization had no metallurgy or wheel technology, they developed complex writing and astrological systems, and created sculptural works in stone and flint. Like the Inca, the Maya also had command of fairly advanced agricultural and construction technology. Throughout this time period much of this construction, was made only by women, as men of the Maya civilization believed that females were responsible for the creation of new things. The main contribution of the Aztec rule was a system of communications between the conquered cities. In Mesoamerica, without draft animals for transport (nor, as a result, wheeled vehicles), the roads were designed for travel on foot, just like the Inca and Mayan civilizations.

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