Warming up.

Date: 2015-10-07; view: 570.

Grammar: Subjunctive Mood. Emphatic Constructions. Suppositional Mood.

THE AGE OF POLYMERS

III. Make a short presentation (up to 7 minutes) describing the current global economic crisis. Use texts 40, 41 from SUPPLEMENTARY READER and other sources.

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The Cold War was a fight to the death between two ways of life, one which advocated free trade and democracy, and the other which believed in a command [government-controlled] economy and political unity. What made the war so vicious was that both sides – government and peoples – believed, not only that their way was better, but that it was absolutely essential to the future happiness of humanity.

Stalin wanted Russia to rule the world and there was no way he was ever going to stop unless someone stopped him. It wasn't just America – the whole free Western world was aware of the threat.

And what would life have been like in a world dominated by Stalin? The Communists murdered and imprisoned their own people by the million. They oppressed Muslims and Christians alike. They sent in the tanks to any Iron Curtain country which looked like it wanted to be free. Reagan called the Soviet Union “the evil empire”; and he was right.

Speech Strategy: PERSUASION.

1. Could you give a definition of a polymer?
2. What is the material capable of being shaped into virtually any form?
3. What do you think is the origin of the word "polymer"?
4. What polymers could you name?
5. What is the difference between a plastic and a polymer?
6. Give two examples of the polymers we eat.
7. What can you say about the following: starch (крахмал), cellulose, and proteins (белки)?

2. Listen to or look through the following text and say if it contains the answers to the questions you've just discussed:

Life depends fundamentally on organic polymers. If it were not so, we wouldn't have food, clothing, shelter and transportation.

Indeed, nearly all of the material needs of man could be supplied by natural organic products. The list of these materials and things made of them might be very long: wood, fur, leather, wool, cotton, silk, rubber, oils, paper, paint and so on. The organic polymers which these things are made from include: proteins, cellulose, starch, resins, and a few other classes of compounds.

But for the complexity and fragility of the molecules of the natural organic polymers they wouldn't have defied the attempts to analyse their molecular structure until very recently.

There would be no industry of man-made organic polymers, were it not for modern methods of physical and chemical analyses which uncovered the principles that govern the properties of the natural polymers. One could list the principal products such as fibres, synthetic rubbers, coatings, adhesives and a lot of materials called "plastics". Plastics and synthetic coating are already in common use. It is desirable that they should be used on a large scale, and get further developed.

Synthetic polymers now available already possess several of the properties required in a structural material. They are light in weight, easily transported, easily repaired, highly resistant to corrosion and solvents, and satisfactorily resistant to moisture. It would be necessary to add that they have long-lived durability and resistance to high temperatures. A very important question could arise over whether synthetic polymers could be made inexpensive enough to compete with the structural materials such as metals and ceramics. The answer could be - "yes".

It might seem odd that man came rather late to the investigation of organic polymers as the principal means of supporting life. The natural polymers such as proteins, cellulose and others dominated his existence and even in ancient times people used these materials.

Yet as late as the end of the 19th century polymer chemistry got little attention.

Chemists attacked sugar, glycerol, fatty acids and other ordinary organic compounds — dissolving, precipitating, crystallizing and distilling them to learn what these substances were composed of.

But only feeble efforts were made to investigate such common materials as wood, starch, wool, and silk. The substances composing these materials couldn't be crystallized from solutions, nor could they be isolated by distillation.

It was only in the 20th century that the scientists began thorough investigation of these materials. Having used some powerful physical instruments, an electron microscope, viscosimeter, X-ray diffraction apparatus, they could have revealed the polymers in all their intricacy. Their molecules were incredibly large, the molecular weights running as high as millions of units, whereas simple organic substances such as, for instance, sugar and gasolene have molecular weights in the range of only about 50-500.

Giant molecules can be composed of a large number of repeating units, they being given the name "polymer" from the Greek word poly (many) and meros (a part). Many polymers have the form of long, flexible chains. If the chemists had not found that out, they wouldn't have been able to synthesize artificial polymers. This has led to the establishment of industries producing synthetic fibres and numerous polymeric materials, many of which were less expensive and superior in various ways to the natural materials.

3. Look through the text again and choose the suitable title out of the given ones:

1. The Age of Plastics.
2. The Importance of Proteins.
3. The Nature of Polymeric Materials.
4. Man-made Polymers.

4. Look through the text once more and put the numbers of the given plan in the order of events they occur in the text:

1. The history of polymers.
2. Natural organic products.
3. The molecules of polymers.
4. Discoveries made by modern methods.
5. The importance of organic polymers.
6. New industries of man-made organic polymers.
7. Properties of synthetic polymers.

5. Read the text thoroughly with a dictionary and answer the following questions:

1. What does the life depend on?
2. Why does life depend upon organic compounds?
3. What is the list of materials needed for life?
4. What do organic polymers include?
5. What have modern methods of physical and chemical analyses uncovered?
6. What products appeared on the basis of the discovery of polymers?
7. What properties do synthetic polymers possess?
8. Did people use natural polymers in ancient times?
9. What were those polymers?
10. When did scientists begin thorough investigation of natural organic polymers?
11. What have they found out about polymers?
12. What are the molecules of polymers composed of?

6. Give Russian equivalents to the following English words, word combinations and chemical terms:

nouns: means, needs, existence, clothing, wood, intricacy, moisture, attention, fragility, establishment.

verbs: list, require, defy, repair, uncover, compete

adjectives: resistant, superior, available, giant, expensive, feeble, odd

adverbs: recently

prepositions and conjunctions: until, whereas

word combinations: as late as, on a large scale, it is desirable, long-lived durability, in the range of, in common use

chemical terms: glycerol, rubber, diffraction, oils, resins, distil, proteins, ceramics, fibre, fatty acids, cellulose, starch, adhesives, coating, solvent, precipitate, solution, dissolve

7. Find in the text synonyms to the following words:

1. wants, 2. weakness, 3. tools, 4. complexity, 5. oppose, 6. demand, 7. provide, 8. register, 9. discover, 10. obtainable, 11. humidity, 12. contend, 13. withstanding, 14. strange, 15. weak, 16. huge, 17. elastic, 18. currently, 19. better

8.Give chemical terms to the following definitions:

1. Any of large group of organic compounds found in all living organisms.
2. A synthetic or naturally occurring polymer used in making plastics.
3. A polysaccharide that consists of a long unbranched chain of glucose units.
4. A liquid that dissolves another substance or substances to form a solution.
5. A process of boiling a liquid and condensing and collecting a vapour.
6. A suspension of small particles produced in a liquid by chemical reaction.
7. A homogeneous mixture of a liquid with a gas or solid.