Notes on the Text

1. In this respect — в этом отношении

2. A great deal of — много

3. The electrons in a metal proved thus to move freely — таким образом оказалось, что электроны в металле двигаются свободно

TEXT. SOLID STATE

If you took a paper clip and bent it, it would stay bent, it wouldn’t spring back and it wouldn’t break. The metal of which the clip is made is ductile. Some other materials are not ductile at all. If you tried to bend a glass rod (unless you are holding it in a flame), it would simply break. It is brittle. In this respect as in many others, glass behaves quite differ­ently from a metal. The difference must lie either in the particular atoms of which metals and glass are made up or in the way they are put together, probably both. There are of course many other differences between metals and glass.

Metals, for example, conduct electricity and are therefore used for electrical transmission lines, glass hardly conducts electricity at all and can serve as an insulator. Glass being transparent, it can be used in windows whereas a sheet of metal even more than a millionth of an inch thick is quite opaque. It is of course interesting to understand the reasons of these differences in behaviour.

During the past 20 years studies of this kind have been called solid-state physics, or sometimes since the subject includes a great deal of chemistry, just “solid state”. It is a major branch of science that has revealed new and previously unsuspected properties in materials. Solid-state physics has become one of the most important branches of technology. It has given rise to technological progress. Having studied this branch of technology, engineers could understand much better the phenomenon of quantum mechanics as it is applied to solids. Though solids, of course, were the subject of exper­imental investigation long before quantum mechanics was invented.

If we considered the fact known since the earliest studies of electric currents, we should remember that metals conduct electricity well and most other materials do not.

It is only the discovery of electron that could help th«$ scientists to understand some of these facts well. With the discovery of electron it was assumed that in metals some or all of the atoms had lost an electron and that in insulators such as glass they had not. The electrons in a metal proved thus to move freely, whereas the electrons in insulators do not. Why did this happen in metals? This very question had to await the discovery of quantum mechanics. The next ques^ tion was: “How are” the atoms arranged?

As far as this question is concerned we can say that solids can be divided into two classes: crystalline and amorphous. In the crystalline group,- which- is the largest and includes the metals and most minerals, the atoms are arranged in a regular way. In some metals (for instance copper and nickel), they are backed together. In other metals (such as iron, for example), they are arranged in the form of a cube. The com­monest of the amorphous group of solids appears in glass, its atoms are put together in a more disordered way than those of a metal.

The structure of an amorphous material is much more difficult to discover than that of a crystalline solid and consi? derable effort is being made to learn more about the arrange­ment of atoms in such materials.

Much has been learned about solids but much is still to be; learned. There is a number of problems which are to be,¹ solved. No wonder that many scientists have been workfngi at this interesting, so-called “solid-state” science.

Remember the following words and word combinational to bend (bent, bent) inch (in.) current '

mi|

reason reasonable opaque to reveal subject

in respect of probably probability to behave sheet

t© await to remember to happen as far as regular

Ex. 5. Answer the following questions:

1. What metal can be called ductile? 2. What would hap pen if you tried to bend a glass rod? 3. What is the different between glass and metal? 4. What is the reason of these differ ences? 5. What was assumed with the discovery of electrons!

3. Into what classes can solids be divided? 7. Which clas; is the largest? 8. How are the atoms arranged in metals:

8. How are the atoms arranged in glass? 10. What have man) scientists been studying for many years?

Ex. 6. Choose the Russian equivalents from the right column:

a great deal of

whereas

particular

partial

loss

lost

long before as far as as soon as

тогда как особый потеря частичный

задолго до (того как) как только поскольку, насколько потерянный

много, большое количество

Ех. 7. Find the pairs of antonyms and remember them:

order, together, transparent, separately, opaque, thick conductor, thin, insulator, regular, to gain, disorder, to lose irregular.

Ex. 8. Give the missing forms of the following verbs:

bent ... staying ...

hold ... lose ...

became ... study ... try ...

Ex. 9. State the types of the Adverbial Clauses of^Condition. Translah the sentences into Russian:

1. A system will remain in equilibrium provided th< temperature and pressure are maintained constant. 2. If the liquid phase underwent a slight change in composition al constant temperature, there would be changes in the partia vapour pressures p_x and p₂. 3. If the second phase is solic instead of gaseous, we shall have, for example, a salt solutior

in contact with ice. 4. If an electric field could be applied to a perfect vacuum, there would be no separation of positive and negative electricity, because there would be no electrons and no positive ions or nuclei in the empty space. 5. Had they investigated the properties of the substance, they would have been careful. 6. Were two bodies placed in contact with each other, the temperature of the hot body would fall while that of the cold one would rise. 7. Water vapour could be condensed into a liquid if we took away heat or if we decreased its volume. 8. If a vapour were superheated, it would behave approximately as a gas. 9. Had the gas been cooled instead of heated, the heat supplied would have become the heat given out by the gas. 10. Unless the cathode C were cooled, it would overheat and emit gases.

Ex. 10. Open the brackets translating the Russian words into English:

1, Each allotrope of a given substance is associated with а (конкретным, особым) quantity of energy. 2. One should (помнить) that in many crystals the atoms occupy almost the same relative position as they would in a close-packed structure. 3. (Как) the volume (так и) the shape can be al­tered by applying considerable force. 4. You should be very careful when working, as this glassware is very (хрупкая).

5. This investigation (вскрыло) very interesting new facts about the nature of crystalline solids. 6. Glass being (про­зрачно) it can be used in windows. 7. Some substances occur naturally in the form of large (правильных) crystals. 8. (В этом отношении) glass behaves quite differently from a metal.

8. Metals are quite (непрозрачны). 10. Hence it was very difficult (обнаружить) whether this sheet was opaque or transparent.

Ex. 11. State parts of speech the words in bold type belong to:

1. The constant temperature at which the solid phase may form is the freezing point of the liquid. 2. The form of this figure was irregular. 3. The solid is the familiar form of a substance at temperatures below its melting point. 4. The physical state in which a substance exists at ordinary temper­ature and pressure is a prominent property. 5. The scientists state this new substance is quite unstable for their experi­ment. 6. The uses of substances depend on the properties they possess. 7. He uses these new methods and gets good results. 8. The freezing point of a liquid is the temperature at which the solid and liquid forms of the substance are in equilibrium at a total pressure of one atmosphere. 9. The effect of changes in temperature on the vapour pressure of the solid is greater than on the vapour pressure of the liquid.

8. Once the stable form has been attained it cannot be direct­ly changed again into a less stable form.

Ex. 12. Translate the following sentences, mind the functions of “would":

1. The scientists said that that discovery would greatly improve the production. 2. That insulator wouldn’t allow the current to flow freely. 3. Before this new technique had been discovered, they would use old methods in their work.

4. If the water flowed through a straight uniform passage with perfectly smooth walls, there would be no resistance and no energy would be lost. 5. If we were to make accurate meas­urement, it would be necessary to use this new measuring device. 6. It would be difficult to fulfil this work without his help.

Ex. 13. Open the brackets translating the Russian words into English:

1. If you (пытались бы) to bend a glass rod when it is _; not heated, it (сломался бы). 2. If this glass (было бы) trans- i parent, it (могло бы использоваться) in windows. 3. If you f try (согнуть) this glass rod, it (сломается) as it is brittle.

^! 4. If they (изучали) solid last year, it (было бы) not so diffi­cult to understand these new phenomena. 5. This substance ; (можно было) used as an insulator. 6. This question (был бы i. решен) provided you (помогли) them. 7. If the electron trans­fer (имело бы место, произошел бы), the atom which has lost the electron (стал бы) a cation. 8. If a liquid (охлажда­ется), its molecules (теряют энергию). 9. If the cooling process i (проводился бы) slowly enough, the particles which consti- I tute the solid (могли бы располагаться) into definite posi- / tions with respect to each other.

Ex. 14. Read the text and retell It:

Crystalline Substances

In some cases, particularly among organic compounds, the process of solidification means the coming together of the gaseous molecules and their final packing together in the crystal.

In the majority of solids, however, the identity of the molecules is lost, and the crystal is a system of atoms in which each is linked to its neighbours in a pattern which extends throughout the crystal. The crystal itself is regarded as a giant molecule.

A crystalline solid usually consists of a number of small crystals which cannot easily be studied individually. Some substances, for instance, quartz, mica, calcite, and diamond, can occur naturally in the form of large crystals. Any partic­ular crystalline solid has a definite volume and a definite shape. The volume and the shape could be changed if consid­erable force were applied.

Ex. 15. Translate the text using a dictionary:

Allotropy

A given chemical substance whether elementary or com­pound may frequently assume more than one form. This phenomenon is known as allotropy, and the different forms of the substance which exhibit allotropy referred to as alio- tropes.

Several allotropes of a substance involved often show re­markable differences of physical and chemical properties. If an allotrope can exist indefinitely in a given physical condition without changing even in part into some other allotrope, it is stable under those conditions. An allotrope changing into another allotrope is unstable under those con­ditions.

Change from one allotrope to another is never instanta­neous, the time taken for completion of the change varying in different cases from a few seconds to years. The speed with which the change takes place depends on the nature of the substance and on the temperature. It would therefore be possible for an allotrope which is unstable under given condi­tions to exist in them for a considerable time.

Each allotrope of a substance is associated with a particu­lar quantity of energy.

Ex. 16. Listen to the following tape-recorded text and discuss it;

Properties of Solids

The molecule^ of solids are close to each other, they are vibrating in a fixed position. There is a strong force of attrac­tion between molecules in a solid. Because of the strong at­traction between molecules, solids have certain properties. If we examined solids thoroughly, we should find that these properties are: tenacity,¹ hardness, malleability, ? and duc­tility.⁸

Tenacity is a measure of solid’s resistance to being pulled apart. Steel has a high tensile strength; concrete has a much lower tensile strength. Hardness is a measure of a substance’s

ability to scratch ⁴ another substance. The diamond is the hardest solid, it being able to scratch all other substances.

Malleability refers to a solid’s ability to be hammered or rolled into thin sheets. Gold is famous for its malleability, copper, tin and aluminum being other examples of malleable

materials. , . . ,, , _f

Ductility is the ability to be drawn out ⁵ in the form oi

wires.⁶

Notes

1. tenacity — вязкость

2. malleability — ковкость

3. ductility — пластичность

4. to scratch — царапать

5. to draw out — вытягивать

6. wire — проволока

LESSON 20

Grammar: 1. The Subjunctive Mood.

2. Whether.

Ex. 1. Pronounce the following words:

clothing ['klouSigJ fur [fa:] leather [ЧеЗэ] wool [wul] cotton ['kotn] protein ['proutkn] cellulose ['seljulous] fragility [fra'dsiliti] defied attempts [di'faid a'tempts]

synthetic [sin'0etik] adhesive [ad'hi:sivj corrosion [кэ'гоизп]

moisture ['moistj’a] inexpensive [^niks'pensiv] glycerol ['glisaral] to precipitate [ta pri'sipiteit precipitate [pri'sipitit] feeble ['fi:bl] thorough ['0лгэ] viscometer [vis'kamita] intricacy ['intrikasi] incredibly large [m'kredabl 'lads]

superior [sju'piaria] cheap [tfi:p]

Text: The Nature of Polymeric Materials.

Ex. 2. Read the following words, mind the stresses:

molecule ['mahkjul] — molecular [mou'lekjula] product ['pradakt] —produce [pra'dju:s] analysis [a'naelasis] — analyse ['aenalaiz] synthesis ['sinGisis]—synthesize ['sin0isaiz] polymer ['palima] —polymeric [,poli'menk] structure ['strAktfa]—structural ['strAktfaral]

Ex. 3. Read the following word combinations:

organic polymers; natural organic products; complexity of molecules, structural materials; resistant to corrosion* satisfactory resistance; ancient times; an electron microscope!

Ex. 4. Translate the following word combinations:

material needs, man-made polymers, long-life durability, until very recently, principal products, a large scale.

№ 1

№ 2

1. It would be interesting to see our new labor­atory.

2. He would come if he were free.

3. He could take part in this work, if he were not so busy.

4. He might answer this question if you helped him.

1. It is important that he should take part in

our research.

2. It is unlikely that this experiment should be interesting.

3. He suggests that this new method should be used.

4. Read attentively lest you should make mis­takes.

Study and remember the following charts:

Ex. 5. Make up sentences according to the models:

Model I: In your place I should take part in the discussion today.

to attend his lecture to find out the composition of the mixture to follow this method not to pay attention to his words

M о d e 1 II: It is necessary that you should examine this substance.

he to solve the question we to be present

she to send for him

they to detect the particles

Model III: He proposed that they should take their examination soon. _t

suggest he not to translate this article demand she to discuss the problem

insist we to work out a new method

Ex. 6. Open the brackets using the correct verb forms:

1. It is important that this new invention (to be used) for peaceful purposes. 2. It is necessary that the solution (to be heated) to a high temperature. 3. They suggested that this chart (to be learned). 4. The scientist insists that this new technique (to be applied).

Ex. 7. Translate the following sentences according to the model:

Model: Nobody knew at that time whether a chain reaction was possible at all.

В то время никто не знал, возможна ли цепная реакция вообще.

1. The scientists wanted to find out whether these new substances could be produced on a large scale. 2. The question could then be raised as to whether the reaction rate was enough. 3. He wanted to reveal whether these compounds had been known in the ancient times. 4. Sometimes it is difficult to say whether a given substance is a mixture or a chemical compound.

Ex. 8. Translate the following sentences into Russian:

Note*, to make—делать to make up—составлять

to make for—cno- to make use—использовать собствовать

1 Inorganic chemistry is the study of those substances which make up the dead material of the universe. 2. The chemical industry makes use of isotope instruments to su­pervise a number of chemical processes. 3. Any process in which oxygen is made to combine with a given substance is called oxidation. 4. Free hydrogen, if it could normally exist is made up of diatomic molecules H : H. 5. Heating makes for the acceleration of the particles.