EARLY HISTORY OF ELECTRICITY

Let us now turn our attention to the early facts, that is to say, let us see how it all

started.

History shows us that at least 2,500 years ago, or so, the Greeks were already

familiar with the strange force (as it seemed to them) which is known today as

electricity. Generally speaking, three phenomena made up all of man's knowledge of

electrical effects. The first phenomenon under consideration was the familiar

lightning flash –a dangerous power, as it seemed to him, which could both kill

people and burn or destroy their houses. The second manifestation of electricity he

was more or less familiar with was the following: he sometimes found in the earth a

strange yellow stone which looked like glass. On being rubbed, that strange yellow

stone, that is to say amber, obtained the ability of attracting light objects of a small

size. The third phenomenon was connected with the so-called electric fish which

possessed the property of giving more or less strong electric shocks which could be

obtained by a person coming into contact with the electric fish.

Nobody knew that the above phenomena were due to electricity. People could

neither understand their observations nor find any practical applications for them.

As a matter of fact, all of man's knowledge in the field of electricity has been

obtained during the last 370 years, or so. Needless to say, it took a long time before

scientists learned how to make use of electricity. In effect, most of the electrically

operated devices, such as the electric lamp, the refrigerator, the tram, the lift, the

radio, and so on, are less than one hundred years old. In spite of their having been

employed for such a short period of time, they play a most important part in man's

everyday life all over the world. In fact, we cannot do without them at present.

So far, we have not named the scientists who contributed to the scientific

research on electricity as centuries passed. However, famous names are connected

with its history and among them we find that of Phales, the Greek philosopher. As

early as about 600 B. C. (that Is, before our era) he discovered that when amber was

rubbed, it attracted and held minute light objects. However, he could not know that

amber was charged with electricity owing to the process of rubbing. Then Gilbert, the

English physicist, began the first systematic scientific research on electrical

phenomena. Rediscovered that various other substances possessed the property

similar to that of amber or, in other words, they generated electricity when they were

rubbed. He gave the name "electricity" to the phenomenon he was studying. He got

this word from the Greek "electrum" meaning "amber".

Many learned men of Europe began to use the new word "electricity" in their

conversation as they were engaged in research of their own. Scientists of Russia,

France and Italy made their contribution as well as the Englishmen and the Germans.

FROM THE HISTORY OF ELECTRICITY

There are two types of electricity, namely, electricity at rest or in a static

condition and electricity in motion, that is, the electric current. Both of them are made

up of electric charges, static charges being at rest, while electric current flows and

does work. Thus, they differ in their ability to serve mankind as well as in their

behaviour. Let us first turn our attention to static electricity. For a long time it was the

only electrical phenomenon to be observed by man. As previously mentioned at least

2,500 years ago, or so, the Greeks knew how to get electricity by rubbing substances.

However, the electricity to be obtained by rubbing objects cannot be used to light

lamps, to boil water, to run electric trains, and so on. It is usually very high in voltage

and difficult to control, besides it discharges in no time.

As early as 1753, Franklin made an important contribution to the science of

electricity. He was the first to prove that unlike charges are produced due to rubbing

dissimilar objects To show that the charges are unlike and opposite, he decided to call

the charge on the rubber– negative and that on the glass–positive.

In this connection one might remember the Russian academician V. V. Petrov.

He was the first to carry on experiments and observations on the electrification of

metals by rubbing them one against another. As a result he was the first scientist in

the world who solved that problem.

Who does not know that the first man to get the electric current was Volta after

whom the unit of electric pressure, the volt, was named? His discovery developed

out of Galvani's experiments with the frog. Galvani observed that the legs of a dead

frog jumped as a result of an electric charge. He tried his experiment several times

and every time he obtained the same result. He thought that electricity was generated

within the leg itself.

Volta began to carry on similar experiments and soon found that the electric

source was not within the frog's leg but was the result of the contact of both

dissimilar metals used during his observations. However, to carry on such

experiments was not an easy thing to do. He spent the next few years trying to invent

a source of continuous current. To increase the effect obtained with one pair of metals,

Volta increased the number of these pairs. Thus the voltaic pile consisted of a

copper layer and a layer of zinc placed one above another with a layer of flannel

moistened in salt water between them. A wire was connected to the first disc of

copper and to the last disc of zinc.

The year 1800 is a date to be remembered: for the first time in the world's

history a continuous current was generated.

Volta's Short Biography. Volta was born in Como, Italy, on February 18, 1745.

For some years he was a teacher of physics in his home town. Later on he became

professor of natural sciences at the University of Pavia. After his famous discovery

he travelled in many countries, among them France, Germany and England. He was

invited to Paris to deliver lectures on the newly discovered chemical source of

continuous current. In 1&19 he returned to Como where he spent the rest of his life.

Volta died at the age of 82.

ELECTRICITY

It is impossible to imagine our civilization without electricity: economic and

social progress will be turned to the past and our daily lives completely transformed.

Electrical power has become universal. Thousands of applications of electricity

such as lighting, electrochemistry and electrometallurgy are longstanding and

unquestionable.

With the appearance of the electrical motor, power cables replaced

transmission shafts, gear wheels, belts and pulleys1 in the 19-th century workshops.

And in the home a whole range of various time and labour saving appliances have

become a part of our everyday lives.

Other devices are based on specific properties of electricity: electrostatics in

the case of photocopying machine and electromagnetism in the case of radar and

television. These applications have made electricity most widely used.

The first industrial application was in the silver workshops in Paris. The

generator – a new compact source of electricity – was also developed there. The

generator replaced the batteries and other devices that had been used before.

Electric lighting came into wide use at the end of the last century with the

development of the electric lamp by Thomas Edison. Then the transformer was

invented, the first electric lines and networks were set up, dynamos and induction

motors were designed.

Since the beginning of the 20th century the successful development of

electricity has begun throughout the industrial world. The consumption of electricity

has doubled every ten years.

Today consumption of electricity per capita is an indicator of the state of

development and economic health of a nation. Electricity has replaced other sources

of energy as it has been realized that it offers improved service and reduced cost.

One of the greatest advantages of electricity is that it is clean, easily-regulated

and generates no by-products. Applications of electricity now cover all fields of

human activity from house washing machines to the latest laser devices. Electricity is

the efficient source of some of the most recent technological advances such as the

laser and electron beams. Truly electricity provides mankind with the energy of the

future

PRACTICAL UNITS

The three practical units, the ohm, ampere, and volt, provide standards for

comparison. They are defined as follows –

The ohmis the first primary unit, and the international ohm is defined as the

resistance offered to an unvarying electric current by a column of mercury at the

temperature of melting ice, 14.4521 gm. in mass, of uniform cross-sectional area and

of length 106.300 cm.

The ampereis the second primary unit. The international ampere is the unvarying

electric current which, when passed through a solution of nitrate of silver in water, in

accordance with a specification, deposits silver at the rate of 0.00111800 gm. per

second.

The voltis the third primary unit and is the electric pressure which, when applied

steadily to a conductor whose resistance is one international ohm, will produce a

current of one international ampere. Further, the international watt is the energy

expended per second by an unvarying electric current of one international ampere

under an electric pressure of one international volt.

In addition to the practical construction of the ohm as defined above it may be

derived in absolute measure as it has the dimensions of a velocity.

СЕМЕСТР

Задание на семестр

1. Подготовить грамматический и лексический материал к семинару (задание № 1),выполнить письменно упражнения (задание № 2)к каждому из трех уроков, подготовить чтение и перевод текстов к каждому из этих уроков (задание № 3).Выучить лексический минимум.

2. Выполнить письменно контрольную работу № 1.

3. Подготовить чтение и перевод текстов к 1 семестру из пособия по дополнительному чтению.

КОНТРОЛЬНАЯ РАБОТА № 1

ПРИМЕЧАНИЕ. Выполненную контрольную работу студент должен предоставить в институт для проверки и рецензирования в сроки, установленные учебным планом 1 семестра.

Перед написанием контрольной работы выполните следующие задания:

Прочитайте и переведите текст «Еenergy ».

ENERGY

In the language of science energy is the ability to do work. There are various forms of energy, such as heat, mechanical, electrical, chemical, atomic and so on.

One might also mention the two kinds of mechanical energy–potential and kinetic, potential energy being the energy of position while kinetic energy is the energy of motion. It is well known that one form of energy can be changed into another. A waterfall may serve as an example. Water falling from its raised position, energy changes from potential to kinetic energy. The energy of falling water is generally used to turn the turbines of hydroelectric stations. The turbines in their turn drive the electric generators, the latter producing electric energy. Thus, the mechanical energy of falling water is turned into electric energy. The electric energy, in its turn, may betrays formed into any other necessary form.

When an object loses its potential energy, that energy is turned into kinetic energy. Thus, in the above-mentioned example when water is falling from its raised

position, it certainly loses its potential energy, that energy changing into kinetic energy.

We have already seen that energy of some kind must be employed to generate the electric current. Generally speaking, the "sources of energy usually employed to

produce current are either chemical as in the battery, or mechanical, as in the electromagnetic generator. Chemical sources of current having a limited application, the great quantities of electric energy generated today come from various forms of mechanical energy.

The rising standards of modern civilization and growing industrial application of the electric current result in an increasing need of energy. Every year we need more and more energy. We need it to do a lot of useful things that are done by electricity. However, the energy sources of the world are decreasing while the energy needs of the world are increasing. These needs will continue to grow as more motors and melted metals are used in industry and more electric current is employed in everyday life. As a result, it is necessary to find new sources of energy.

The sun is an unlimited source of energy. However, at present, only a little part of solar energy is being used j directly. How can we employ solar energy directly

to produce useful energy? This is a question which has interested scientists and inventors for a long time. Lavoisier and other great scientists of the past melted

metals with the help of solar furnaces. Today, solar furnaces illustrate just one of the numerous ways to harness the sun. Using semiconductors, scientists, for example ,have transformed solar energy into electric energy.

.Выпишите все незнакомые слова в свой рабочий словарик.

К собеседованию подготовьте контрольное чтение и устный перевод текста.

ЗАДАНИЕ 1.Перепишите в тетрадь и переведите письменно третий, четвертый и пятый абзацы.

ЗАДАНИЕ 2.Задайте 5 видов вопросов вопросы к выделенному предложению. Запишите их и переведите на русский язык.

ЗАДАНИЕ 3.Выпишите из текста предложения, содержащие модальные глаголы.

ЗАДАНИЕ 4.Найдите в тексте и выпишите слова с окончанием «-s», определите, какой частью речи являются эти слова и какую функцию это окончание выполняет, т.е. является ли оно:

1. показателем 3-го лица единственного числа глагола в Present Indefinite;

2. признаком множественного числа существительного;

3. показателем притяжательного местоимения существительного.

ЗАДАНИЕ 5.Выпишите из текста и переведите предложения с оборотом “there + be”, учитывая правила перевода.

ЗАДАНИЕ 6.Найдите в тексте и выпишите случаи употребления глаголов в страдательном залоге, определите время. Переведите их на русский язык.

ЗАДАНИЕ 7.Выпишите из текста выражения, в которых существительные употребляются в функции определения и переведите их.

ЗАДАНИЕ 8.Перепишите и переведите следующие предложения, отмечая, соответствуют ли они содержанию текста словами «да» или «нет».

We have already seen that energy of some kind must be employed to generate the electric current.

Generally speaking, the "sources of energy usually employed to produce current are either chemical as in the battery, or mechanical, as in the electroоwater.

Chemical sources of current having a limited application, the great quantities of electric energy generated today come from various forms of kinetic energy.

ЗАДАНИЕ 9.Перепишите предложения, заполняя пропуски , где это необходимо. Подчеркните вставленные отрывки Переведите предложения на русский язык.

One might also mention the two kinds of mechanical energy–………., potential energy being the energy of position while kinetic energy is the energy of motion.

It is well known that one form of energy…………………. A waterfall may serve as an example. Water falling from its raised position, energy changes from potential………….. The energy of falling water is generally used to turn the turbines……………... The turbines in their turn drive the electric generators, the latter………………... Thus, the mechanical energy of falling water is turned………………. The electric energy, in its turn, may betrays formed into any other necessary form.When an object loses its potential energy, that energy is turned…………... Thus, in the above-mentioned example when water is falling from its raised position, ………………, that energy changing into kinetic energy.

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