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Ex.1. Translate the following sentences into Russian: TaKKaK, nocKoflbKy

Not e: since

C, c Tex nop, KaK; co BpeMeH14

1. Since we know all the properties of the substance, we can use it in our experiment. 2. Many interesting investigations have been done since the foundation of this research laboratory at our plant. 3. Helium belongs to the same group as argon since it does not combine with other elements. 4. I have not carried out any experiments in the laboratory since I graduated from the Institute. 5. We couldn'tfinish our work since we had no necessary devices. 6. Since the kinetics of the reaction was studied at room temperature, the results were good. 7. This element has been known since the 19th century.

Ex.2. Translate the text in written form, mind modal verbs:

The chemical industry needs instruments for accurate measuring. Good measuring instruments are able to give rapid results. Without modern instrumentation chemical processes were often controlled by a human operator who had to decide what needed to be done. It was rather difficult to do. The results had often to be checked thoroughly. There are many different kinds of measuring instruments and there is much information about the instruments which are to be used in chemical plants. The purpose of all measuring devices is to control a chemical reaction. In a process controlled by a human operator, the temperature, for example, can be read from a thermometer. The operator is to decide whether the

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temperature is all right. Then he has to make some measurements. In the automated system, some mechanical or electrical device must replace the human operator to decide whether a process correction is needed and, if so, the extent of the necessary correction.

LESSON V.

Notes on the Text.

1.ushered in a new era - S03SeCn1I10 HOSYIO apy

2.to call for - Tpe60saTb, HY>K,lJ,aTbC51

3.half-life - nepllto,q nOIlypacna,qa

4.to dispense with - 06XO,qIltTbC51 6e3

T E X T . RADIOACTIVITY

The discovery of natural radioactivity by the French researcher Henri Becquerel ushered in a new era in science and technology. This phenomenon is based on the principle that substances occurring in nature, such as uranium and radium, are transformed into other chemical elements, independently of influences from outside, emitting different kinds of radiations which blacken a photographic plate as this is done by the rays of light.

In the decades following this discovery thousands of scientists in many countries of the world have systematically investigated the essence and the application of radioactivity and of the radiation emitted by radioactive nuclides.

The basic practical and theoretical work done by the Curies, the work by E.Rutherford who achieved an artificial nuclear transformation, the development of apparatus for the detection of radioactive nuclides by Geiger and Muller,

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the discovery of neutron by the English physicist J.Chadwick, the discovery of the artificial radioactivity by the Curies and the discoveries of some other scientists are the milestones in the history of radioactivity.

The field of application of radioactive nuclides in chemistry, physics, biology, agriculture, medicine and industry has rapidly expanded.

One of the most interesting fields of applications of radioactivity is the determination of the age of carbonaceous materials, that is materials containing carbon, by measurement of their radioactivity due to carbon 14.

This technique of radiocarbon dating permits the dating of samples containing carbon with an accuracy of around 200 years.

At the present time the method involved can be applied to materials that are about 25,000 years old.

Today the range of application of radioactive nuclides comprises all branches of research work. Thus, for example, certain medical examinations call for short lived radioactive nuclides in order that the human organism should not be exposed too long a period of time to radiation, whereas a radioactive nuclide which excites the luminescent material should have a long half-life.

Investigations into the reaction mechanisms in chemistry, researches in the field of physics, the explanation of vital processes in plants, animals and man, diagnostics of diseases of the human body, the testing of metallic and ceramic materials are but a few fields of science and technology which today, 91 years after the discovery of radioactivity, cannot dispense with radioactive nuclides and the radiation emitted by them.

It should be added that a considerable number of

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research problems has only become soluble by the use 0' radioactive nuclides.

Remember the following words and word combinations:

Study and remember the following charts:

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N 3 1.The experiment being carried out in our laboratory is very important for my work.

2.Being carried out in our laboratory the experiment can be studied thoroughly by our students

Ex. 1. Remember the following nouns:

Ex.2. Translate the following words of the same root:

1.to consider, consideration, considerable, considerably;

2.to produce, production, productivity, product;

3.to depend, dependence, dependent, dependently, independent;

4.to use, use, useful, useless, usefulness;

5.to increase, increase, increasingly;

6.to measure, measurement, measurable;

7.to add, addition, additional;

8.to discover, discovery, discovered.

Ex.3. Read the text fluently and answer the questions that follow:

Half-Life

The discovery of radioactivity raised a number of

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questions. In the beginning research-workers tried in vain to influence the phenomena of radioactivity by pressure and increased or reduced temperatures. They understood that the forces involved could not be controlled by the means available at the time.

Further they have found that certain elements were transformed into other elements completely uninfluenced by measures taken.

The first clue that could lead to the formulation of some laws was the half-life which is defined as the time required for disintegration of one half of the atoms of a sample of an radioactive element.

1.What questions did the discovery or radioactivity raise?

2.What did research-workers try to do in the beginning?

3.What did research-workers understand?

4.What have they found further?

5.What was the first clue that led to the formulation of some laws?

6.How can the half-life be defined?

Ex.4. Read the text and retell it:

The Discovery of X-Rays and Radioactivity

Several great scientific discoveries were made in a period of a few years, beginning in 1895. These discoveries made great changes in chemistry as well as in physics.

X-rays were discovered in 1895, radioactivity was discovered in 1896, the new radioactive elements polonium and radium were isolated in the same year, and the electron was discovered in 1897.

W.Rontgen reported that he had discovered a new kind

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of rays called X-rays. These rays are produced when electricity is passed through a tube.

The rays are outside of the tube, they radiate from the place where the cathode-ray electrons strike the glass.

Soon after the discovery of X-rays the French physicist Henri Becquerel investigated some minerals containing uranium. He found that these minerals emit rays that, like

X-rays, can pass through black paper and expose a photographic plate. He also found that the radiation produced by the uranium minerals could, like X-rays, discharge an electroscope.

Marie Curie began a systematic investigation of

"Becquerel radiation" using the electroscope as a test. She found that natural pitchblende, an ore of uranium, is several times more active than purified uranium oxide.

LESSON VI.

Notes on the Text

1.nevertheless - TeM He MeHee

2.just as - TalOKe KaK

3.to result from - npoHcxo.qHTb, npoHcTeKaTb

T E X T . CHEMICAL AND PHYSICAL CHANGES

An iron rod held in the fire long enough increases in energy content until it becomes too hot to hold in the unprotected hand. Nevertheless the rod is still iron, and when cooled to its original temperature, its properties are just as they were before.

The heating and the subsequent cooling of the rod are examples of physical changes.

A physical change may result in a more or less temporary alteration of a few of the properties of a

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substance involved, but no change of composition results from it and most of the altered properties usually regain their former value.

Changes of this type are numerous and many of them are familiar to everyone. As an example we may take the behaviour of ice when it is heated.

At first when heated the ice melts, when further heated, the liquid water boils forming the gaseous water (or the steam, as it is usually called). If the steam is cooled, the process is reversed - when cooled sufficiently, the ice results. The substance present in every instance was water. This experiment shows that there are three physical states in which the substance may exist.

If the rod concerned is placed in a container of hydrochloric acid, it will be noted that bubbles begin to form on the rod. If the rod involved is left in the acid for some time, the evolution of gas will continue. When examined, it will be found that the rod has diminished in mass or disappeared altogether. The liquid in the container if examined will have a greenish colour.

If evaporated, a mass of greenish crystals will be obtained. The crystals will have totally different properties. This is an example of a chemical change. So, a chemical change may be called a chemical reaction or simply a reaction, the substances entering into a chemical reaction are called reactants.

Phenomena accompanied by radical changes of substances are called chemical phenomena.

Remember the following words and word combinations:

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Ex.1. Translate the following sentences according to the given models:

Mod e I I: The question involved is to be solved today.

1.Bonpoc, 0 KOTOPOM MAeT pe'lb,AOn>KeH 6blTb peweH ceroAHR.

2.AaHHblM Bonpoc AOn)KeH 6blTb peweH

cerOAHR.

1.The elements involved varied in their properties greatly. 2. The rate of the reaction depends on the nature of the substance involved. 3. The acid involved acted as a catalyst. 4. The importance of the technique involved was evident to everyone.

Mod e I 11: The discovery followed by many experiments resulted in new Investigations in chemistry.

OTKpbITHe, 3a KOTOPblM nocneAOBano MHOro onblTOB, npHBeno K HOBblM HccneAoBaHHRM B 06nacTH XHMHH.

1.The lecture followed by practical hours took place in our club. 2. These rays uninfluenced by the magnetic field were examined by our workers. 3. The substance affected by a magnetic field must be a metal. 4. The analysis followed by an examination gave unexpected results.

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Mod e I Ill: When (if) heated, water turns into a steam. npM HarpeBaHMM (KorAa BOAY HarpeBalOT)

BOAa npeBpaLltaeTCs:l B nap.

1. When asked about this work, he couldn't answer anything. 2. If carried out carefully, the experiment can give reliable data. 3. When shown this chart, pay attention to the figures.

Ex.2. State the sentences where the verb form with the suffix "-ed" is Participle 11:

1. A piece of iron placed in a container with an acid can diminish in mass. 2. They placed the iron rod in a container with water.3. Carbon uncombined is a solid. 4.

Some elements combined resulted in new elements. 5. They combined some obtained data. 6. They produced good products. 7. The products produced were good.

Ex.3. Translate the following parts of the sentences: 1. When heated sufficiently, ... 2. If cooled to 20°C,... 3. Translated into Russian ... 4. The question involved ... 5.

When removed, ... 6. If examined under the microscope, ...

7. Produced at the plant. .. 8. When produced at the plant, ... 9. If hold in the hand, ... 10. When changed greatly, ...

Ex.4. Translate the sentences paying attention to the translation of "no" before the noun:

1. No change took place in the solution in the air. 2. No solution could be formed in such conditions. 3. No temperature change was observed in the sample used. 4. No oxidation of any substance takes place without the reduction of some other substance. 5. No material is perfectly elastic even at a very low stress. 6. When liquid

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