5. Retell the text.

Text 3

Cables

Words and word combinations:

An insulated bundle – изолированная связка

threadlike fibers – нитевидные волокна

electric current – электрический ток

to distribute – распределять

to transmit – передавать

electronic devices – электронные устройства

intercontinental – межконтинентальный

fiber-optic cables – оптико-волоконные кабели

widespread – широко распространенный

artificial satellites – искусственные спутники

radio waves – радио волны

practical means – удобные средства

Cable, in electricity and communications, is an insulated bundle of wires or threadlike fibers that carry electric current or pulses of light. Cables are widely used to distribute electric power and to transmit communications signals. They are also used to connect parts of computers and other electronic devices. Electric cables range from intercontinental underwater cables that carry an electric current as small as one-thousandth of a watt to roadside electric lines that are capable of carrying thousands of watts of electricity. Fiber-optic cables transmit communications signals in the form of pulses of light.

Cables came into widespread use in the second half of the 1800’s, when telegraphs and telephones became common. Since the mid-1900’s, communications systems that use radio signals broadcast from transmitters on earth or in artificial satellites have begun to replace some cables. For example, telephone companies now use radio waves to carry most long-distance telephone calls. Communications satellites send television programs and other electronic messages throughout the world. In many cases, however, cables still provide the most practical means of communication.

Text 4 The development of cables Words and word combinations:

To extend – тянуться

wooden poles – деревянные столбы

necks of broken bottles – горлышки разбитых бутылок

to attempt – пробовать, делать попытку

bottom – дно

bodies of water – формы воды

to shield –защищать

a tough insulation – крепкая изоляция

hemp – пенька

rubberlike – подобный каучуку

gutta-percha – гутта-перча

Early cables. In 1844, the American painter and inventor Samuel F. Morse completed the first long-distance telegraph cable in America. The cable extended from Baltimore to Washington, D.C. It was strung on wooden poles, and the necks of broken bottles were used for insulation. In the years that followed, many telegraph lines were built throughout the United States and Canada. In 1861, a telegraph cable linking California with the East Coast was completed.

During the late 1840’s, numerous attempts were made to lay telegraph cables along the bottom of various bodies of water. Many of these attempts failed because the insulation on the cables was not able to shield the conductors from the water. In 1851, two English brothers, Jacob and John Brett, succeeded in laying a telegraph cable across the English Channel. In making their cable, they used a tough insulation consisting of a fiber called hemp and a rubberlike substance called gutta-percha.

They also used iron to strengthen their cable.