ATOMIC POWER FOR ROCKETS

The heart of a nuclear-rocket engine is the reactor that converts nuclear energy into heat.

The fuel of the reactor consists of a special kind of "isotope" of uranium, called Uranium-235. When properly.

bombarded with neutrons, the uranium nuclei break up or "fission" into a pair of fragments and emit more neutrons in the process, thus keeping the reaction going.

The fission process releases energy and the excess energy is carried away by the neutrons and by gamma rays. Since all of the fragments and most of the neutrons and gamma rays are stopped within the reactor, the energy that is released by U-235 fission will heat the reactor.

For making a nuclear-rocket engine thermally efficient the reactor's temperature must be as high as possible. The melting point of uranium, 2,070 degrees F, sets a theoretical limit. Graphite, which withstands much higher temperatures, is a very good material for the reactor's "moderator". So all present experimental reactors for nuclear-rocket engines are made of U-235 metal powder placed in graphite.

A cold gas, the hydrogen, enters several hundred narrow passages drilled through the graphite-uranium reactor core and is heated almost to the white-hot operating temperature. On coming from the passages, the hot gas expands through a nozzle in which it attains supersonic speed.

The exhaust speed of the nuclear-rocket engine can probably reach 23,000 to 30,000 feet per second, which is twice as much as from a rocket engine using chemical combustion of hydrogen and oxygen.

Вариант 6

I. Перепишите следующие предложения, подчеркните в каждом из них герундий или причастие, определите его функцию в предложении; предложения переведите на русский язык.

On splitting atom in the reactor heat is developed.
Duplicating the extreme conditions present at the birth of the universe is very difficult.
The subatomic stuff got stabilized combining into particles that make up matter today.

II. Перепишите и письменно переведите на русский язык сложные предложения, содержащие придаточные предложения условия.

In case there is some alteration in space, the particles will react.
If all photons were not identical, lasers would nor operate.
Had no forces acted in the region, the field had got a numerical value of zero.

III. Перепишите предложения, подчеркните в каждом из них объектный или субъектный инфинитивные обороты, предложения письменно переведите на русский язык.

This method permitted the tests to be carried out faster.
The scientist considered the results to be satisfactory.

3. Change in the properties of subatomic particles is considered to be a phase change.

The rapid cooling is thought to have generated several phase changes.

IV. Перепишите и письменно переведите на русский язык следующий текст.

THE WORLD IS MADE OF SUBATOMIC PARTICLES

According to contemporary physicists, the world is made of several types of objects, collectively referred to as subatomic particles. (These particles can also be thought of as manifestations of something yet more fundamental, known as quantum fields.) There may be as many as 10**9 identical copies of some of these particles in the present universe. The forms of matter familiar to us, both living and nonliving, on the earth and in the heavens, are all composed of various combinations of only three types of subatomic particles - protons, neutrons, and electrons. Dozens of other types of particles can be produced momentarily in the laboratory, however, and are thought to have existed in large numbers in the early universe.

All subatomic particles are defined by a few qualities that they may possess, such as mass, spin, and electric charge. Two particles are of the same type, if all of these qualities agree. Otherwise, they are considered to be different particles. Particles of the same type are, as far as we know, truly identical in these properties of mass, spin, and charge rather than just very similar. If all photons, the particles that make up light, were not identical, lasers would not operate.

The subatomic particles readily convert into one another when they collide. The kinetic energy of motion of light particles can be converted into the energy associated with mass (rest energy) of heavy particles. In many cases, even isolated particles can convert spontaneously into others, if the latter are less massive. In all such transformations, only a few properties, such as the total electric charge, remain unchanged. The subatomic particles do not act like changeless building blocks imagined by some Greek philosophers. In the last few years physicists have realized that even which subatomic particles exist they have changed radically over the lifetime of the universe.

Вариант 7

Using radioactive isotopes opened up new possibilities for agriculture.
Adding heat we can change the state of the substance.
By cooling we can turn substances into solids or liquids.
They need devices improving the accuracy of measurements.

Provided we use the necessary instruments, the measurements will be correct.
Were You a specialist in this field, we would show you the new installation.
If the information had been received in time, we would have used it in our research.

The scientists believe research and innovations to improve society’s living.
Bigger telescopes are expected to enable astronomers to examine The Universe better.
Heat causes materials to increase in size.
This appliance is likely to have improved the production process.

IV. Перепишите и письменно переведите на русский язык следующий текст.

SCIENCE AND TECHNOLOGICAL PROGRESS IN MODERN SOCIETY

Natural science is the main characteristic feature distinguishing the present civilization from the other civilizations in the past. From its early beginnings in the sixteenth century, the developments of science have influenced the course of western civilization more and more until today it plays a most dominant role. It is not much of an exaggeration to say that we live in a world that, materially and intellectually, has been created by science.

This point is easy to illustrate on the material level. One merely needs to mention the telephone, the radio, the television, the automobile, and the airplane, or any of the countless devices invented by the application of science. There is hardly an article used in the homes, in the places of work, or in the places of enjoyment that has not been modified by technology based on science; the means of communication that bind the continents into a single community depend on scientific know-how; without modern sanitation it would be impossible to have large centres of population; without modern industry and agriculture it would be impossible to feed, to clothe, and to provide the "abundant life" to this large population.

There is, however, another part of the story less obvious and less well known, but far more important. It is a story of expanding intellectual horizons—the impact of science on the mind of a man. Fundamentally, science is an intellectual enterprise, an attempt to understand the world in a particular way. All the developments mentioned above are but the results, the outcomes of this intellectual activity.

Over the past 150 years the range of human knowledge has been doubled every twelve to fifteen years. In 1930 man knew four times as much as he did in 1900, by 1960 his knowledge had grown sixteenfold.

Вариант 8

Increasing pressure leads to the decrease of gas volume.
There are many methods of solving this problem.
Heating a magnet we lessen its magnetism.
Generators producing electricity get their power from steam turbines.

In case there is no current in the conductor, there can be no electric field around it.
Were there no atmosphere around the Earth, its surface would become too hot by day and too cold at night.
In case there had been no gravitation, the artificial satellites would have moved straight.

This energy makes an electron pass from one orbit to another.
Gravitation makes satellites move round the Earth.
Silicon, selenium and copper oxide are considered to be the most widely used semiconductors.
This scientist is known to have made a few inventions in atomic science.

IV. Перепишите и письменно переведите следующий текст.

MAGNETISM

In studying the electric current, we observe the following relation between magnetism and the electric current: on the one hand magnetism is produced by the current and on the other hand the current is produced from magnetism.

The earliest practical application of magnetism is connected with the use of a simple compass consisting of small magnet pointing north and south.

A great step forward in the scientific study of magnetism was made by Gilbert, the well-known English physicist (1540-1603). He carried out various important experiments on electricity and magnetism and wrote a book where he put together all that was known about magnetism. He proved that the earth itself was a great magnet.

Reference must be made here to Galileo, the famous Italian astronomer, physicist and mathematician. He took great interest in Gilbert's achievements and also studied the properties of magnetic materials He experimented with them trying to increase their attracting power. One of his magnets, for example, could lift objects weighing 25 times its own weight.

At present even a schoolboy is quite familiar with the fact that in magnetic materials such as iron south pole. When iron and steel are magnetized, the molecules arrange themselves in a new orderly way instead of the disarrangement in which they neutralize each other.

Dividing a bar magnet into two parts, one finds that each of the two parts is a magnet having both a north pole and a south pole. Thus, we obtain two magnets of a smaller size instead of a single one of a larger size. Dividing one of these two smaller magnets into two will give us the same result. Thus, we could continue this process, always getting similar results.

On placing an unmagnetized iron bar near a strong magnet, we magnetize it. Rubbing the magnet is nor required for that process. In other words, our iron bar has been magnetized by the strong magnet without rubbing it.

Вариант 9

Using atomic fuel for the production of electricity is one of the main sources of energy.
The students began learning English in September.
A molecule is a compound consisting of two or more atoms.
Using isotopes in measuring the diffusion of metals we got much more accurate data.

Unless the temperature rises, the speed of molecular motion will not increase.
Were the temperature low, the reaction would proceed slowly.
Should the scientist have used this device, he would have obtained more precise results.

The new device enabled the researcher to carry out more complex experiments.
We expect the experiments to be completed by the end of the year.
Kurchatov is known to have investigated the physics of the atomic nucleus.
The capacity of this power station seemed to range from 10,000 to 20,000 kilowatts.

IV. Перепишите и письменно переведите на русский язык следующий текст.

ATOMIC ENERGY

A man trying to see a single atom is like a man trying to see a single drop of water in the sea while he is flying high above it. He will see the sea made up of a great many drops of water but he certainly will not be able to see a single drop. By the way, there are so many atoms in the drop of water that if one could count one atom a second, day and night, it would take one hundred milliard years. But that is certainly impossible.

Man has, however, learned the secret of the atom. He has learned to split atoms in order to get great quantities of energy. At present, coal is one of the most important fuel and our basic source of energy. It is quite possible that someday coal and other fuel may be replaced by atomic energy. Atomic energy replacing the present sources of energy, the latter will find various new applications.

The nuclear reactor is one of the most reliable "furnaces" producing atomic energy. Being used to produce energy, the reactor produces it in the form of heat. In other words, atoms splitting in the reactor, heat is developed. Gas, water, melted metals, and some other liquids circulating through the reactor carry that heat away. The heat may be carried to pipes of the steam generator containing water. The resulting steam drives a turbine, the turbine in its turn driving an electric generator. So we see that a nuclear power-station is like any other power-station but the familiar coal-burning furnace is replaced by a nuclear one, that is the reactor supplies energy to the turbines. By the way, a ton of uranium (nuclear fuel) can give us as much energy as 2.5 to 3 million tons of coal.

The first industrial nuclear power-station in the world was constructed in Obninsk not far from Moscow in 1954. It is of high capacity and has already been working for many years. One may mention here that the station in question was put into operation two years earlier than the British one and three and a half years earlier than the American nuclear power-stations.

Вариант 10

Studying natural phenomena without making observations is useless.
Russian scientists played an important part in solving the problem of atmospheric electricity.
Boiling in the flask the water changes into steam.
The changing pressure was precisely measured.

If a solid is heated, it will usually expand.
Were the temperature increased, the speed of the molecular motion would also be increased.
Provided we had placed a small bulb in a complete circuit, it would have lit up.

The application of electricity caused the substances to change their structure.
The students think this research to be interesting.
Every matter is certain to possess energy.
Batteries and generators are sure to be the most common source of electromotive force.

IV. Перепишите и письменно переведите на русский язык следующий текст.

LIGHTNING

The lightning flash is certainly the earliest manifestation of electricity known to man, although for a long time nobody knew that lightning and atmospheric electricity are one and the same thing. Indeed, for thousands of years people knew nothing about thunderstorms. However, they saw long sparks falling from the dark sky and heard thunder. They knew that these sparks could kill people or strike their houses and destroy them. Trying to understand that dangerous phenomenon, they imagined things and invented numerous stories.

Take the early Scandinavians as an example! They thought that thunderstorms were produced by Thor, the god of thunder. Besides his throwing both thunder and lightning at some people, he was a hammer-thrower. According to the story, his powerful hammer had the property of always coming back to his hands after it had been thrown. The fifth day of the week, that is Thursday, was named after him. A story like that invented by those early Scandinavians could be also heard from other peoples.

However, time flies. Thunderstorms have long stopped being a problem that scientists tried to solve. Now everybody knows that lightning is a very great flash of light resulting from a discharge of atmospheric electricity either between a charged cloud and the earth or between charged clouds.

Even now some people do not like being out during a thunderstorm. Dark clouds cover the sky, turning day into night. There are lightning flashes followed by thunder which can be heard for kilometres around. Needless to say, there is always some danger in a thunderstorm for a very high building or a man standing in the open field. Many years ago people learned to protect their houses from thunderstorms. Coming down from a charged cloud to the earth, lightning usually strikes the nearest conductor. Therefore, it is necessary to provide an easy path along which electrons are conducted to the earth.