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Lesson 28 Science Serves the People



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Lesson 28 Science Serves the People

ELECTRICITY AND MAGNETISM


The first new science to arise after the end of the Newtonian period was electricity, in part because it was almost the only aspect of physical science to which Newton himself had not devoted his attention and where his great prestige did not frighten off lesser investigators. Electricity had had a long and legendary past. The phenomena of electrostatics and magnetism were known to ancient men as early as 600 B.C. The ancient Greek philosophers thought magnetic and electric forces to be of common origin.

Science of magnetism, however, only began when its power could be used to good purpose, as in the com­pass. In its early stages however, magnetism didn't seem to promise any profitable application. It was a philosophic toy and lay a little outside the interests of the time, which were turned so largely to mechanics and the vacuum.

Some experiments with electricity were made in the early eighteenth century. One of them was made by the English amateur Stephen Gray, that led him in 1729 to a discovery of the transmission of electricity. Franklin, in remote Philadelphia heard of experiments with electricity and sent for some electrical apparatus. Having studied the problem Franklin came to the conclu­sion that electricity is a kind of immaterial fluid existing in all bodies, undetectable as long as they were saturated with it. If some was added they became positively charged, if some was removed - negatively. Replacing the fluid by electrons and changing the sign of the charge,-for +, for it is a negatively charged body that has an excess of electrons, Franklin's explanation be­comes the modern theory of electric charge. This simpli­fication was Franklin's serious contribution to electrical theory, but what really impressed the world was his un­derstanding the analogy between electric spark of the lab­oratory and the lightning which he snatched from the sky with his kite and showed that it was electricity. From this he, in his practical way, imme­diately drew the conclusion that it would be possible to prevent the damage due to lightning by the lightning conductor which he tried out in 1753. With this invention electrical science became for the first time of practical use.

Despite all these advances electricity and magnetism remained mysterious and their quantitative study could not begin until some method could be found of measur­ing them. This was the work of Coulomb in 1785. He established that the forces between magnetic poles as well as those between charges of electricity obeyed the same laws as those of gravity, that is, a force proportional inversely to the distance. These experiments enabled the whole apparatus of Newtonian mechanics to be applied to electricity, but with this difference: that in electricity repulsive as well as attractive forces to be found.



The multiple analogies between electricity and mag­netism made physicists think that there must be some connection between them but it was one very difficult to find. It was not until 1820 that through- another accident at the lecture table, Oersted in Copenhagen found that the electric current deflected a compass needle. He thus joined together, once and for all, the sciences of electric­ity and magnetism. One immediate consequence was the invention of the electromagnet, then the electric telegraph and the electric motor.

Man and Machines

  1. Press a button1 on the wall and a dark room is full of light. Speak
    into a little instrument and people thousands of miles away will hear
    you instantly. Switch on your radio or TV set and you will hear music,
    the latest news or see a play even from remote regions of the globe.

  1. Nowadays people move on land much faster than the speediest
    horses. Powerful motors drive cars, diesel engines run trains from one
    country to another. Under water sportsmen swim swifter than the speediest fish.3

In air people fly hundred times faster than birds.4Supersonic planes fly at twice the speed of sound People enjoy these achievements thanks to the development of science and engineering.

3. We live in the age of machinery i.e. (that is) in the time when
highly productive machines and up-to-date devices take the place of
men for doing work. In industry and agriculture machines
play a most important role. They lighten man's labour and do all the
hard work in mills, factories, mines and farms.

In a number of shops in up-to-date mills and plants automatic ma­chines entirely replace the work of men. In mining industry conveyors and remote control devices make miner's labour safer and easier. They help to produce more ores, coal, oil and gas. In fields tractors and harvester combines replace labour of hundreds of people and help farmers to gather rich crops.

4. Machines help not only factory workers and farmers in their pro­ductive labour. They do part of scientists' and explorers' research work
as well. They enable scientists to reveal the secrets of the universe i.e.
everything that exists on our globe as well as in the outer space. Satel­lites (sputniks) circle the earth, spaceships explore the outer space.
Moon cars (Lunokhods) carry out research programmes on the Moon.

Underwater robots explore the sea bed at a depth of more than 4,000 meters. By means of remote control devices they change tools and lift weights.

Electronic instruments — radars, lasers and masers represent the latest developments of research equipment. They are of great help in all forms of scientific work.

  1. Great and rapid changes take place in science and engineering.
    New branches of science appear: atomic physics, cybernetics, radio-astronomy. Big experimental research programmes are in progress
    in all countries. Mankind is on the eve of space flights to remote stellar
    worlds.

  1. With the development of science and engineering, with the advan­cement of progressive ideas a new man will appear — a man who will
    use his hands less and less, but employ his brains more and more.

At this stage of development mankind will seek new ways that lead to better life, to general abundance. All peoples of the globe will win freedom and independence. The triumph of Reason and Progress will bring happiness and universal peace to the human race.

Automatic Plants in Industry

  1. Here are some facts about a new automatic plant in Moscow. The new plant is truly an enterprise of tomorrow — a factory where men and women are free from manual labour, where machines do all the hard work.

  1. In the high, light and clean halls hundreds of mechanical devices
    act with unprecedented precision and timing. The machine assembly-
    transforms metal into complex machine parts without human inter­vention.

A few people walk quietly round the machines and check their oper­ation. These are operators. They operate separate machines. They keep them working at just the right speed every operator is a very skilled technician with a wide knowledge of machines. He knows machines so well that he can feel the pulse of each machine. If any trouble arises, the operator determines the damage and repairs it quickly, — in seconds. He changes tools and starts the device again. But to repair damage is only a part of his job. To prevent stoppages is even much more important.

  1. The operators are well trained people. A controller sits at a desk.
    He merely watches the illuminated glass panel on which he sees the
    entire machine assembly in graphic form. As he knows the connection
    between the various working processes, he directs various sections and
    shops of the plant.

  1. Machines are used not only to produce high-precision parts. They
    inspect the quality of work. If any stoppage takes place an automatic
    device immediately sends a signal. At every stage of its journey through
    the plant, the part goes through accurate mechanical inspection. A me­chanical device inspects and checks the weight of the part, precision of
    its diameter, solidity of metal. Another mechanical inspector not only
    checks the precision of the complex parts but sorts them out in different
    sizes. The plant of today is a factory which looks more like a first-class laboratory than a plant of jobs for the working people and increasing instability for masses of people.

  1. The socialist system provides the most favorable conditions for
    speedier scientific development, for turning science completely into a
    direct productive force. In socialist countries science serves the all-round
    development of the working man: it lightens the conditions of his work,
    increases the labour productivity, raises his skill and culture, helps
    overcome the essential differences between mental and manual labour,
    increases the well-being of society. Socialist system sets free the talent
    of man and promotes the all-round harmonious development of the
    individual. That is one of its most, or perhaps the most characteristic
    feature.

  1. .The concentration of research in large scientific institutions with
    excellent equipment ensures the best possible opportunities for joint
    research and experimentation. The socialist system creates the most
    favorable conditions for collective scientific and technological research,
    not only in national terms but for the entire socialist commonwealth.

  1. Co-operation by the Academies of Science of the socialist countries
    started in 1962. Its purpose was to focus research on selected problems
    of the natural and social sciences, through co-ordination and division
    of labour among the scientists of socialist countries.


Masers and Lasers

  1. A great technical advance is under way. It is the advancement
    to develop the amazing new scientific devices called "masers" and "lasers".

  1. Hundreds of physicists, engineers, and technicians are working
    in laboratories throughout the Soviet Union, the United States, Great
    Britain and other technically advanced countries. Each month brings
    word3 of new significant advances. Problems and difficulties are many,
    but the achievements are already great and the promise for the future
    is enormous.

  1. Masers and lasers provide the first positive method for generating
    controlled and uniform light, and radiations like light which men cannot
    see with their eyes but can receive with their instruments.

  2. The name "maser" itself provides good clues to follow. It is one
    of the words known as acronyms—each letter stands for a word in
    a significant phrase: "Microwave Amplification by Stimulated Emission
    of Radiation.

  1. Laser has the same origin, but replaces the M for "microwave"
    with an L for "light". (You use other acronyms constantly. Do you know,
    for example, about the basis for the word radar? It is an acronym for
    "Radio Detecting and Ranging").

  1. The year 1951 may stand as the birthday of the idea of the maser,
    as such.

  1. Various scientists in the Soviet Union and in the United States
    were thinking along similar lines, for important technical problems have away of inspiring similar solutions in different places — science deve­lops "freely with interchange of information.

8. While sitting in a park one spring morning, the originator of the
maser Dr. Charles H. Townes, was thinking about very small things —
microwaves.

9. Townes was a physics professor at Columbia University in New
York City. He tried to find ways to extend to still higher frequencies
the range of microwaves that one can use in communication work.

Lesson 29 Radioelectronics



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