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Alexander Graham Bell biography
Dátum pridania:21.11.2002Oznámkuj:12345
Autor referátu:aradvan
 
Jazyk:AngličtinaPočet slov:3 202
Referát vhodný pre:Stredná odborná školaPočet A4:11.1
Priemerná známka:2.97Rýchle čítanie:18m 30s
Pomalé čítanie:27m 45s
 
Bell, Alexander Graham (1847-1922), American inventor and teacher of the deaf, most
famous for his invention of the telephone.

Bell was born on March 3, 1847, in Edinburgh, Scotland, and educated at the universities of Edinburgh and London. He immigrated to Canada in 1870 and to the United States in 1871. In the United States he began teaching deaf-mutes, publicizing the system called visible speech. The system, which was developed by his father, the Scottish educator Alexander Melville Bell, shows how the lips, tongue, and throat are used in the articulation of sound. In 1872 Bell founded a school to train teachers of the deaf in Boston, Massachusetts. The school subsequently became part of Boston University, where Bell was appointed professor of vocal physiology. He became a naturalized U.S. citizen in 1882.

Since the age of 18, Bell had been working on the idea of transmitting speech. In 1874, while working on a multiple telegraph, he developed the basic ideas for the telephone. His experiments with his assistant Thomas Watson finally proved successful on March 10, 1876, when the first complete sentence was transmitted: "Watson, come here; I want you." Subsequent demonstrations, particularly one at the 1876 Centennial Exposition in Philadelphia, Pennsylvania, introduced the telephone to the world and led to the organization of the Bell Telephone Company in 1877.

In 1880 France bestowed on Bell the Volta Prize, worth 50,000 francs, for his invention. With this money he founded the Volta Laboratory in Washington, D.C., where, in that same year, he and his associates invented the photophone, which transmits speech by light rays. Other inventions include the audiometer, used to measure acuity in hearing; the induction balance, used to locate metal objects in human bodies; and the first wax recording cylinder, introduced in 1886. The cylinder, together with the flat wax disc, formed the basis of the modern phonograph.

Bell was one of the cofounders of the National Geographic Society, and he served as its president from 1896 to 1904. He also helped to establish the journal Science by financing it from 1883-1894.

After 1895 Bell's interest turned mostly to aeronautics. Many of his inventions in this area were first tested near his summer home at Baddeck on Cape Breton Island in Nova Scotia, Canada. His study of flight began with the construction of large kites, and in 1907 he devised a kite capable of carrying a person.
 
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