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BIG ENCYCLOPEDIA FOR CHILDREN AND ADULTS
Who Invented the Elevator? Detailed answer
Directory / Big encyclopedia. Questions for quiz and self-education Did you know? Who invented the elevator? The elevator was not invented by any one person, but this idea has been developed over a long time. Mechanisms operating on the principle of an elevator have been used for many centuries. The ancient Greeks lifted objects using blocks and winches. A block is a wheel with a groove along which the rope slides. A winch is a mechanism with a wider wheel or drum to which the end of a rope is attached. When turning the drum with a handle, the rope is wound or unwound from the drum. If the rope is passed through the block, it can raise and lower the load. In the XNUMXth century, the "flying chair" was invented. It was designed to lift people to the upper floors of buildings and was driven by a system of weights and blocks. The chair and its mechanism were outside the building. However, the "flying chair" has not found wide application. In the first half of the XNUMXth century, the elevator already existed, but was used mainly for lifting goods. Later, a steam engine was used to turn the drums of these hoists. Most of all, people were afraid that the ropes holding the elevator might burst, and the elevator would fall down. But when Elisha Otis invented accident-proof safety devices, elevators became very popular. At the same time, hydraulic lifts began to be used to raise and lower cabins, which use high-pressure fluid. The electric elevator we use today was invented by the German engineer Werner von Siemens. Author: Likum A.
What is the age of the earth? We will never be able to give an exact answer to this question. Since time immemorial, man has been interested in the age of the Earth, and many myths and legends have appeared on this subject, which seemed to give an answer. But it was only about 400 years ago that this question began to be approached from a scientific point of view. At this time, it was proven that the Earth revolves around the Sun (in other words, that the Earth is part of the solar system), and now scientists knew where to start. From finding out the age of the Earth, what was needed was to explain how the solar system was born. How did the sun and all the planets come about? One of the theories is called the nebular hypothesis. According to this theory, once upon a time a huge cloud of hot gas rushed through space, which decreased in size and heated up more and more. As the gas cloud decreased, it threw out clumps of gas. Each of these clumps formed into a planet, and the remaining mass gathered in the center and became the Sun. Another explanation is called the planetesimal theory. According to it, millions and millions of years ago there was a huge accumulation of small solid bodies called planetesimals in space, with the Sun in the middle. A huge star passed nearby, under the influence of which parts of this mass came off. These parts attracted small planetesimals to themselves, just as snow sticks to a snowball, and so the planets appeared. Regardless of the correctness of this or that theory, astronomers have calculated that this happened about 5 years ago! But not only astronomers, but also other scientists were engaged in solving this issue. They tried to find the answer by figuring out how many years it took the Earth to become what we know it to be. They determined the time it took for the oldest mountains to erode and the time for the oceans to accumulate their current amount of salt. As a result of all studies, these scientists agreed with astronomers that the age of the Earth is approximately 5 years.
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