B. Past Perfect 1. She hoped I (to pay) for the tickets. 2. When we came the plane (to take off). 3. I went to sleep as soon as the show (to finish). 4. By the end of the year he (to complete) five courses. 5. When they came home mother (to do) everything about the house. 6. I went to see the sights after I (to buy) a map of Kyiv. 7. We knew our itinerary only after the leader of the group (to tell) us. 8. After I (to spend) all the money I turned to my father. 9. She understood the letter after she (to read) it a second time. 10. We (to keep) waiting until we lost patience.

C. Future Perfect. 1. When the father returns from his round the world trip his son (to become) a grown-up man. 2. By the end of this year I (to read) all the books of this writer. 3. You (to finish) to type my papers by this evening? 4. If you come late, the party (to end). 5. When you come she (to leave). 6. By the end of July you (to pass) your last entrance exam. 7. I'm not sure if I (to translate) this text by Monday. 8. By the time they return from the honeymoon trip we (to rebuild) the house for them.

Exercise 3. Translate the following sentences into Ukrainian. Make the following sentences interrogative and negative.

A. Present Perfect. 1. They have already determined the main properties of the substance. 2. I have known him since 1970. 3. He has just come by car. 4. I have attended lectures on history since May. 5. He has entered the University this year. 6. They have already applied new methods in their research. 7. Our country has developed into a powerful state.

B. Past Perfect. 1. They had already learnt all new English words. 2. He had already seen the film before he watched it on TV. 3. By that time we had already changed our plans. 4. He had never been to doctors. 5. By the end of the last century scientist had made the first attempts to obtain synthetic materials.

C. Future Perfect. 1. We shall have finished the work tomorrow by 5 o'clock. 2. They will have completed the experiment by the end of the year. 3. When you see him next, he will have passed the last exam. 4. The mechanic will have installed the new equipment in our laboratory by the beginning of the New Year.

Exercise 4. Open the brackets and put the verbs into the Future Indefiite or the Future Perfect.

1. He (to receive) the telegram tomorrow. 2. He (to receive) the telegram by tomorrow. 3. I (to do) the exercises by seven o'clock. 4. I (to do) the exercises in the afternoon. 5. By this time you (to take) your examination. 6. You (to take) your examination next week. 7. The teacher (to correct) our dictations in the evening. 8. The teacher (to correct) our dictations by the next lesson.

Exercise 5. Translate the following sentences into English.

А. 1. Я залишив свій зошит вдома. 2. Де Петро? - Він ще не прийшов. 3. Що ти робиш? - Я читаю англійське оповідання. - Скільки сторінок ти вже прочитав? - Я прочитав вже вісім сторінок. 4. Мину-лого року ми їздили у Київ на виставку. З того часу я не був у Києві.

В. 1. Ми читали книгу, яку я купив у Києві. 2. Студенти переклали текст до кінця пари. 3. Він подякував мені за те, що я зробив для нього. 4. Вчора ми обговорили фільм, який дивились декілька днів тому.

С. 1. Я зроблю цю роботу до кінця тижня. 2. Викладач перевірить наші роботи до наступного заняття. 3. Нова школа буде побудована до 1 вересня. 4. Зустріч відбудеться до 7 години вечора.

VOCABULARY NOTES

Task I. Read and memorize the following words. Translate the sentences.

1. to invent - винаходити. Morse invented a code that used dots and dashes for letters of the alphabet.

2. source - джерело. The sun is unlimited source of energy.

3. application - застосування. Electrical engineering has to do with practical applications of electric energy.

4. property - якість, властивість, характеристика. The most important property of electron is that it is electrically charged.

5. device - прилад, механізм. Our scientists are preparing programmers for automatic devices.

6. to generate - виробляти, генерувати. A cell is the simplest arrangement that generates electric energy.

7. design - проект, дизайн. People who come to the Aircraft Fair in Paris see new designs of aircraft from different countries.

8. consumption - споживання The nation's consumption of coal increased last year.

9. without - без. He said that she should not leave the town without him.

10. wide - широкий. It is pleasant to drive along a wide road.

11. to replace - замінити, витіснити. Buses are replacing the trams in cities.

12. efficient - ефективний. Efficient methods were used to increase the quantity of manufactured goods.

13. by-product - побічний продукт. The by-product of combustion consists of carbon dioxide, water and additives (домішки).

14. power - сила, енергія. How much power does this plant consume?

15. to imagine - уявляти. They can't imagine how they will do it.

16. to reduce - зменшувати. He will not reduce the rent of their house.

17. to cover - охоплювати. The town covers five square miles.

18. to transform - перетворити, змінити. You'd never recognize their flat - it's quite transformed.

19. appearance - поява. My appearance at the party was not very welcome.

Task II. Read and translate the text.

Text 7A

Electricity

It is impossible to imagine our civilization without electricity: economic and social progress will be turned to the past and our daily lives completely transformed.

Electrical power has become universal. Thousands of applications of electricity such as lighting, electrochemistry and electrometallurgy are longstanding and unquestionable.

With the appearance of the electrical motor, power cables replaced transmission shafts, gear wheels, belts and pulleys in the 19-th century workshops. And in the home a whole range of various time and labor saving appliances have become a part of our everyday lives.

Other devices are based on specific properties of electricity: electro-statics in the case of photocopying machine and electromagnetism in the case of radar and television. These applications have made electricity most widely used.

The first industrial application was in the silver workshops in Paris. The generator - a new compact source of electricity - was also developed there. The generator replaced the batteries and other devices that had been used before.

Electric lighting came into wide use at the end of the 19^th century with the development of the electric lamp by Thomas Edison. Then the transformer was invented, the first electric lines and networks were set up, dynamos and induction motors were designed.

Since the beginning of the 20^th century the successful development of electricity has begun throughout the industrial world. The consumption of electricity has doubled every ten years.

Today consumption of electricity per capita is an indicator of the state of development and economic health of a nation. Electricity has replaced other sources of energy as it has been realized that it offers improved service and reduced cost.

One of the greatest advantages of electricity is that it is clean, easily-regulated and generates no by-products. Applications of electricity now cover all fields of human activity from house washing machines to the latest laser devices. Electricity is the efficient source of some of the most recent technological advances such as the laser and electron beams. Truly electricity provides mankind with the energy of the future.

Notes to the Text.

1. transmission shafts, gear wheels, belts and pulleys - трансмісійні вали, зубчасті колеса, ремені і блоки

2. time and labour saving appliances - електроприлади, які економлять час та працю

3. induction motors - індукційні мотори

4. per capita - на людину; на душу населення

Exercise 6. Answer the questions on the text.

1. What is this text about? 2. What industrial applications of electricity do you know? 3. What home applications of electricity do you know? 4. Where was the generator developed? 5. Who invented the electric lamp? 6. Do you know who invented the dynamo? 7. Can you imagine our life without electricity? Why?

Exercise 7. Translate these sentences into Ukrainian. Define subject and predicate in the following sentences.

1. That electricity is clean and easily-regulated is its great advantage. 2. The important fact is that electricity offers improved service at reduced cost. 3. That the two scientists Lodygyn and Yablochkov were the first in Russia to work in the field of electrical engineering is well-known. 4. One of the main advantages of electricity is that it does not pollute the environment. 5. The indicator of nation development is how much electricity is consumed per capita. 6. What has been and is being done in environment protection cannot be measured by yesterday's standards.

Exercise 8. Indicate the tense form and the voice of the predicate-verb. Translate these sentences into Ukrainian.

A. 1. I have not cleaned the window yet. I am cleaning it now. I have cleaned it. 2. Bob has a different idea. 3. Last year she passed school leaving exams. 4. We will be studying for our exams at the end of the term. 5. While we were having supper, all the lights went out. 6. Will people speak the same language all over the world? 7. People will land on Mars in the 21^st century. 8. I think cars will be powered by electric batteries in fine years' time and they will not be powered by atomic power in 100 years' time. 9. The Earth is getting warmer because of the increase of carbon dioxide in the atmosphere.

B. 1. It is evident that electricity will be the energy of the future. 2. The transformer was invented and the first electric lines and networks were set up at the end of the 19^th century. 3. New powerful electric stations must be built because it is electricity that offers improved standards of life and work. 4. A combination of electric lines and networks are being set up throughout the country. 5. Electric power has become universal. 6. Electricity is transmitted to distant parts of this country by a combination of electric networks.

Exercise 9. Make a sentence out of the two parts.

1. Electricity 1. have already become universal.

2. The applications of electricity in 2. has completely transformed home and industry our everyday life.

3. Electricity was used for the 3. per capita is an indicator of the state first time development of a nation.

4. The generator, a new source of 4. the wide industrial use of electricity electricity began throughout the world.

5. Since the beginning of the 20^th 5. was also developed in Paris.

century

6. Today consumption of 6. for industrial purposes in the electricity silver workshops in Paris.

Exercise 10. Define the function of the verb to have in the following sentences. Translate them into Ukrainian.

Electricity has many useful properties: it is clean and generates no by-products. 2. It has many important applications in industry as well as in our houses. 3. The latest laser devices have found application in medicine. 4. Electricity has provided mankind with the most efficient source of energy. 5. No other source of energy has been so widely used as electricity. 6. We have many various electric devices in our houses. 7. Our lives have been completely transformed with the appearance of electricity. 8. The generator replaced batteries that had been used before. 9. The consumption of electricity has doubled every ten years. 10. Our scientists have succeeded in obtaining a new generation of solid-state lasers (твердотільні лазери). 11. An electron is very small and it has a very small mass. 12. In the application of electronic instruments the engineer must have a knowledge of their characteristics. 13. The first cosmic flight shows man's abilities have no limit; man has only to use his intelligence in order to create conditions under which his talents can develop. 14. Engineers had carried out experimental work long before they proceeded with the design.

Exercise 11. Find synonyms in group A and find antonyms in group B.

A. application, appliance, later, power, use, enable, reach, device, longstanding, make it possible, achieve, energy, transform, old, turn to, most recent.

B. future, unlimited, past, with, necessary, limited, old, unnecessary, without, present

Task III. Read and translate the text

Text 7B

Non-traditional Renewable Sources of Energy.

It is known that much being done in the world today for the development of non-traditional sources of energy. Without them the Earth cannot support its present population of 5 billion people and probably 8 billion people in the 21 st century.

Now we are using traditional power sources, that is, oil, natural gas, coal, water power with the consumption of more than 50 billion barrels per year. It is evident that these sources are not unlimited.

That is why it is so important to use such renewable sources of energy as the sun, wind, geothermal energy and others. Research is being carried out in these fields.

One of the most promising research is the development of power stations with direct transformation of solar energy into electricity on the basis of photo-effect. It was Russia that was the first in the world to develop and test a photoelectric battery of 32,000 - volts and effective area of only 0. 5 sq. m., which made it possible to concentrate solar radiation. This idea is now being intensively developed in many countries.

However, the efficiency of a solar power station is considerably reduced because of the limited time of its work during the year. But it is possible to improve the efficiency of solar power stations by developing different combinations of solar power stations and traditional ones - thermal, atomic and hydraulic. Today some engineers are working at the problem of developing electric power stations with the use of a thermal-chemical cycle. It will operate on products of the transformation of solar energy, whereas the “solar” chemical reactor uses CO₂ and water steam of the thermal power station. The result is that we have a closed cycle.

In Kamchatka there are geothermal power stations operating on hot water-steam mixture from the depths of about a kilometer. In some projects water will be heated by the warmth of mountains at a depth of four-five km.

It is planned that plants working on the energy of the solar heat provided by the sun will be built on a larger scale.

That different wind energy plants are being developed is also well-known. These energy plants can be small (of several kilowatts) and large powerful systems.

It is important that all these advances in developing new sources of energy and improving the old ones help to solve the energy problem as a whole and they do not have negative effects on the environment.

Notes to the text

1. renewable sources - відновлювані ресурси

2. promising - перспективний

3. solar energy - сонячна енергія

closed cycle - замкнений цикл

5. wind energy plant - вітрова електростанція

Exercise 12. Read these word-combinations and translate them into Ukrainian.

Chemical energy (reaction), traditional power sources, current electricity, static electricity, to concentrate solar radiation, loss of electrons, zink (copper) electrolyte, direct current, dry cell, primary cell, thermal power station, storage battery, liquid electrolyte, atomic power station, wind energy, solar power station, metal wire, the same number of electrons, opposite direction, net flow of electrons.

Exercise 13. Fill in the blanks with the suitable words.

Electricity, increase, consumers, power, use, generation, reduce, consumption, far, users, application, provide, sources, energy, light

We hear so much these days of local problems of …. Many … are taking steps to … their electricity. … this as a result of the recent … in electricity tariffs for …. We should all try to … less …, by insulating our houses, turning off the … when leaving a room and using less hot water.

We must try to develop alternative … of energy to … electricity for domestic and industrial …. It is known that nuclear power comes to the consumer as electricity, which is clean and convenient form of …. Although nuclear … stations are large, they can be built … from places where people live.

Exercise 14. Fill in the blanks with the antonyms of the words given in bold type.

1. Though the capital investment, that is, the initial cost of building the nuclear power station, is high, the cost of generating electricity from a nuclear power station is relatively….

2. There is a limited supply of fossil fuels such as oil, gas and coal on the earth, but a supply of natural uranium is….

3. Cheap impure coal produces much more CO₂ than ……… coal of high quality.

4. It is evident to all that an old inefficient power station is more dangerous to the environment than a …… power station.

Task IV. Speak about:

Electricity - its nature, history and development.

VOCABULARY NOTES

Task V. Learn the following words and word-combinations.

to get along досягати успіху

ambitious честолюбивий

adult дорослий

to work part-time працювати неповну к-сть роб. годин

after-school activity позааудиторна діяльність

average пересічний

It goes without saying. Само собою зрозуміло.

hardworking працьовитий

either …or… чи. чи.

to baby-sit доглядати за дітьми

spoiled зіпсований

drug abuse зловживання наркотиками

pregnancy вагітність

crime злочин

alchohol abuse зловживання алкоголем

to look forward з нетерпінням чекати

Task VI. Read and translate the topic.

The youth of America.

What about the American dream of getting along in the world? What does it mean to a young man in the U. S. A.? Well, to my mind, most of them are very ambitious and keep their eyes on the stars.

At 18 years of age young people in the U. S. A. become adults, that is, they get most of the rights and duties of adults. But before this happens, however, they are simply teenagers. Many teenagers are making positive, important contributions to their home, school and society.millions of young people in the United States are getting ready for the future exams or working part-time after school and during weekends. Some are working at hospitals or other places which require part-time workers.

Schools provide American students with much more than academic education. Students learn about the world through various after-school activities. More than 80 percent of all students take part in sports, student newspapers, drama clubs, choral groups and others.

What are the favorite sports of the youth of America? They prefer football, basketball, wrestling, tennis, boxing, hockey and golf. During their free time students spend much time watching TV. They also listen to music.

The average American youth listens to music on the radio about three hours every day. It goes without saying that pop music is the favourite of teenagers. America's young people are mostly hardworking. Many have after school jobs. Nine out of ten teenagers either have a job or would like to have one. Many young people work part-time on weekends or after school at fast-food restaurants, baby-sit for neighbours, hold delivery jobs or work in stores. Many take part in community service organizations.

Some are active in church and religious-group activities. Others belong to youth groups such as Girl Scouts. Some people think that teenagers of the U. S. A. today are spoiled as compared with those of earlier times. However, most young people in the United States do not have problems with drinking, drug abuse, teen pregnancies or crimes. Drug use has decreased among young people during the last years, though alcohol abuse has increased.

Most American young people look forward to their future with hope and optimism. They pay great attention to education and careers.

Exercise 15. Answer the questions

1. What does it mean to become adults in the USA? 2. What knowledge do American schools provide their students with? 3. What sports belong to favourite in the USA? 4. Are America's young people mostly hardworking? Prove it. 5. What other activities are the young American engaged in?

Exercise 16. Read and translate word-combinations.

To get along, it goes without saying, as compared with, to look forward to, important contribution, school and society, various after-school activities, to take part in sport, students free time, with hope and optimism, great attention to education and careers.

Exercise 17. Translate into English.

1. Молодь Америки мріє побачити світ. 2. Молоді люди беруть активну участь у житті суспільства. 3. Підлітки у Америці працюють протягом вільного часу. 4. Молодь із задоволенням займається спортом. 5. Дискотеки - цікавий вид відпочинку для американських підлітків та студентів. 6. Американські молоді люди є дуже працелюбні. 7. Релігія займає важливе місце у житті американської молоді.

Task VI1. Reproduce the topic in your own words.

Key dates in science

1644 Evangelista Toricelli, an Italian physicist, discovered the principle of the barometer.

1682 The English astronomer Edmund Halley described and charted the orbit of the comet.

1687 The English physicist Isaac Newton published his book Principia, in which he proposed the laws of motion and gravity.

1704 Isaac Newton wrote Optics, a book about prisms and light.

1712 The English inventor Thomas Newcomen built the first atmospheric steam engine.

1752 The American scientist Benjamin Franklin showed that lightning is a form of electricity.

Lesson 8

Grammar. Часи групи Perfect Passive

Text 8A. Changes in Matter

Text 8B. The Science of Ice

Topic. The Engineering Profession

Відмінювання дієслова to tell в часах групи Perfect Passive

to have + been + PII (III форма дієслова)
Present	Past	Future
I We You have been told They He She has been told It	I He She It had been told We You They	I He She It will have been told We You They

Exercise 1. Translate the following sentences into Ukrainian. Determine the Tense and the Voice of the verb:

1. Have all these books been read? 2. The letter has just been typed. 3. She showed me the picture which had been painted by her husband. 4. He has been told everything, so he knows what to do now. 5. The door has been left open. 6. She said that the new timetable had not yet been hung up on the notice board. 7. The light has not yet been turned off. 8. By three o'clock everything had been prepared. 9. The papers had been looked through and corrected by the next lesson. 10. The letter has just been sent. 11. Invitations have been sent to all the old pupils to be present at the school's anniversary. 12. This man has been much spoken of. 13. Have your compositions been handed in? 14. What has been said is true. 15. After the facts had been thoroughly examined by her, she no longer felt worried. 16. This mountain has never been climbed before. 17. She told me that those newspapers had been carefully put away where they would not be lost. 18. Why have these cups been put here in this cupboard?

Exercise 2. Choose the right form of the predicate.

1. Two new engineers (were introduced, have been just introduced) to the head of the department. 2. All the texts were looked through yesterday and not a single mistake (was found, had been found). 3. Many students (are enrolled, have been enrolled) in universities this year 4. The translation (is not finished, has not been finished) yet. It (will be finished, will have been finished) by the end of the month. 5. These journals (was brought, had been brought) by my sister before I returned from Kyiv. 6. This problem (is discussed, has been discussed) much in the press lately. 7. By the year 2030 human labour in industry (will be replaced, will have been replaced) by robots. 8. Today's global economy (is formed, has been formed) by market, not by the principles of ecology. 9. Cosmologists (are thrown, have been thrown) into confusion by the discovery that the universe is only as old as the stars it contains.

Exercise 3. Use Passive Voice in the following sentences.

1. By three o'clock the workers had loaded the trucks. 2. I have translated the whole text. 3. When I came home, they had eaten the sweets. 4. They have made a number of important experiments in this laboratory. 5. They have forgotten the story. 6. Has anybody explained the rules of the game to you? 7. They haven't brought back my skates. 8. I haven't yet translated the article. 9. Has the secretary typed the letters? 10. They have already discussed the novel. 11. The students have written the test paper without mistakes. 12. They have built excellent shelters for tourists in these mountains. 13. They have recently built a huge plant in the town.

Exercise 4. Translate the following sentences into English using Perfect Passive.

1. За директором вже послали. Зачекайте трохи. 2. Ці листи переглянуті. Їх можна відправляти. 3. Вас вже запросили на вечірку? 4. Коли мама прийшла, обід вже був приготовлений. 5. Цей переклад буде закінчений через кілька днів. 6. Стаття повинна бути перекладена до п'ятої години. 7. Ці квіти щойно зірвали. 8. До того часу як він приїхав, лист був вже отриманий. 9. Чи принесли вже книжки з бібліотеки? 10. Цей кінотеатр був збудований до того, як ми приїхали сюди. 11. Цей роман вже перекладений п'ятьма мовами. 12. Коли я повернуся додому, усі мої валізи будуть вже складені. 13. Куди поклали книжки? 14. Чи послали за ліками? - Так, їх шукають. 15. Новий завод буде побудований до початку наступного року. Він буде оснащений найновішим обладнанням.

VOCABULARY NOTES

Task I. Read and memorize the following words. Translate the sentences.

1. change - зміна. Let's hope there will be a change in the weather.

2. compound - суміш, сполука.common salt is a compound of sodium and chlorine.

3. evaporation - випаровування. When water was heated evaporation took place.

4. to evaporate - випаровувати (ся). Heat evaporates water.

5. to make up - складати. Animals and vegetables are made up of water and cells.

6. matter - речовина, матерія. By studying and experimenting man came to know the structure of matter.

7. mixture - суміш. Air is a mixture of gases.

8. to occur - траплятися. When did the accident occur?

9. property - властивість. The chemical properties of iron.

10. to distinguish - розрізняти. Elements are characterized by some properties distinguishing them from other substances.

11. to retain - утримувати; зберігати. She retains a clear memory of her schooldays.

12. solid - твердий. When water freezes and becomes solid, we call it ice.

13. substance - речовина, матерія. Water, ice and snow are the same substance in different forms.

14. unique - унікальний, незвичайний. This stamp is unique; there are no others like it.

15. charge - заряд. Atoms are electrically neutral having no electric charge in their normal state.

16. to dissolve - розчиняти. Sugar dissolves in water.

17. to affect - впливати. Smoking affects health.

18.rust - іржа. Plastics do not rust.

Task II. Read and translate the text.

Text 8A

Changes in Matter

Transformations are of two kinds, known as physical and chemical changes. Physical changes are those which affect the state or condition of matter without changing its composition. There is no change in the composition of a substance when it is transformed from the liquid to the gaseous state by heating or from the liquid to the solid state by cooling, and vice versa. Thus, in all three states, steam, water, and ice are all the same substance, made up of the simpler substances, hydrogen and oxygen. The state, but not the composition is affected by the process of heating or cooling.

All matter is made up of atoms. An atom consists of a nucleus containing positively charged protons and neutrons that have no electrical charge. Negatively charged electrons travel around the nucleus. The chemical and physical properties of matter can be explained in terms of electrons, protons, and neutrons. Substances containing only one type of atoms are called elements. When two or more elements are combined in a chemical reaction, a compound is formed. Each compound has its own unique chemical and physical properties. A molecule is made up of two or more atoms. Molecules can be formed by atoms from different elements as well as some atoms form a single element.

By changes in the composition of a substance are meant changes such as when a solid mass is made to fine powder, salt or sugar is dissolved in water. It is clear that such transformations like the changes from one state of matter to another, do not affect the composition of the material. The fine powder of a substance may be made solid again, and we get back the salt or sugar unchanged by evaporating the water.

Chemical changes, however, are those matter changes in which a change of composition does take place and the new substance formed will not return to its original state, unless it is subjected to another chemical change. Thus iron, when it is affected by moist air, is slowly transformed into iron rust entirely different in its properties from the original iron. The new substance will not become iron again when it is allowed to stand, although the iron can be obtained from it if it is subjected to the proper condition.

Thousands of physical and chemical changes take place in nature, and in a laboratory it is possible to cause many other changes artificially which do not occur naturally. For example, by subjecting air to very great pressure and cooling it is possible to transform it to the liquid state - a physical change; while by means of changing the materials which are combined, or the conditions under which they are combined, many substances will be produced by the chemist, some of which are formed in nature while others are not. In observing these transformations, it is important to be able to distinguish between physical and chemical changes.

Exercise 5. Answer the questions.

1. What are the two kinds of transformations described in the text? 2. What do we call physical changes? Give some examples of physical changes. 3. What do changes in the condition of substances mean? 4. What do we call chemical changes? Give some examples of chemical changes. 5. Does a change of composition take place in a chemical change? 6. In what way is it possible to liquefy atmosphere?

Exercise 6. Find synonyms to the following words and translate them into Ukrainian.

change, to consist of, to go back, completely, to permit, to get, to happen, for instance.

Exercise 7. Find antonyms to the words given below and translate them into Ukrainian.

unlike, old, changed, same, solid, artificially, few, rapidly.

Exercise 8. Make up sentences.

1. two, are, of, kinds, there, changes, and, physical, chemical. 2. physical, thousands, place, of, nature, changes, take, in. 3. physical, do, change, transformations, of, not, composition, the, substances.

Exercise 9. Define the tense-form of the predicate and translate the sentences into Ukrainian.

1. When careful studies of the transformation of one form of energy into another had been carried out, the law of the conservation of energy was stated. 2. After the body has been heated, it will get larger in size. 3. By the end of the year all the experiments necessary for the completion of our research will have been made. 4. Before the first human astronaut went into space, much work had been done with the sputniks, carrying dogs and small animals. 5. It has been proved by many experiments that when energy is changed from one form to another the whole amount of energy remains unchanged.

Task III. Read and translate the text.

Text 8B.

The Science of Ice

Why Does Ice Float?

Water is different. With most everything on Earth except freshwater, the colder it gets, the more dense it becomes. Take alcohol for instance. If we were to fill up a 1 liter container with pure alcohol at 30 degrees Celsius and then take another 1 liter container and fill it with pure alcohol at 10 degrees Celsius the cooler container of alcohol would weigh more. This is because the cooler alcohol is more dense, so more alcohol molecules can fit in the same container. This is true with freshwater too, up to a point. But at about 4 degrees Celsius water reaches its densest point. Amazingly, as water cools further, it actually becomes less dense.

Each water molecule is made of 2 hydrogen atoms and 1 oxygen atom. These are connected to one another by very strong chemical bonds called covalent bonds. Water molecules are connected to each other by much weaker chemical bonds called hydrogen bonds between the positively charged hydrogen atoms, and one negatively charged oxygen atom in a neighboring water molecule.

As water gets colder than 4 degrees Celsius the hydrogen bonds connecting different water molecules adjust to keep the negatively charged oxygen atoms apart. This results in a crystal lattice which begins to form at less than 4 degrees Celsius. This crystal lattice is completely formed at freezing, and is commonly known as ice.

So, why does ice float? Like most things that float, ice floats because it is less dense than liquid water. Ice is about 9% less dense. When ice forms, it takes up about 9% more space than it did as a liquid. Thus, a 1 liter container of ice weighs less than a 1 liter container of liquid water, and the lighter material floats to the top. As we said, water is different.

Why Is Ice Slippery?

We all know that ice is very slippery. But why? Can you think of any other solids that are as slippery? There is disagreement as to what causes ice to be so slick. Some researchers have said that ice is slick because the surface partly melts due to pressure and friction.

Other studies have found that friction alone can not account for the slipperiness of ice. These researchers believe that ice is slippery because the surface has unique physical characteristics of both a liquid and a solid. Regardless of the reason, how many of you have ended up on your rear-ends while to get from school to your house on an icy day?

Notes to the Text

covalent bond - ковалентний зв'язок

hydrogen bond - водневий зв'язок

crystal lattice - кристалічна решітка

slick - блискучий, гладенький

to account for - пояснювати

regardless of the reason - не беручи до уваги причину

Exercise 10. Translate into Ukrainian:

freshwater, to fill up a container, up to a point, amazingly, chemical bonds, covalent bonds, hydrogen bounds, positively (negatively) charged, crystal lattice, float to the top, to be slick, due to pressure and friction, slipperiness, unique characteristics, regardless of the reason, to end up on your rear-ends.

Exercise 11. Answer the following questions on the text.

1. Why is water different from the other substances? 2. What molecules is water made of? 3. What bonds are called covalent bonds? 4. What bonds are water molecules connected by? 5. How is a crystal lattice of water called? 6. Why does ice float? 7. What are the opinions concerning the slipperiness of ice? 8. Which of the idea do you share or do you stick to your own?

VOCABULARY NOTES

Task IV. Learn the following words and word-combinations.

engineering інженерна справа

ancient стародавній

occupation заняття

skill вміння

to evolve розвивати

forerunner передвісник

to refine вдосконалювати

ancestor предок

to devise винаходити

irrigation system система зрошення

empirical емпіричний

motive power рушійна сила

to be guided керуватися

to do without обходитись

substantial training грунтовна підготовка

environmental engineering техніка моделюваня експлуатаційних умов

attitude підхід

good judgement розсудливість

to take into account брати до уваги

Task V. Read and translate the topic.

The Engineering Profession

Engineering is one of the most ancient occupations in history. Without the skills included in the broad field of engineering our present-day civilization never could have evolved. The first tool-makers who chipped arrows and spears from rock were the forerunners of modern mechanical engineers. The craftsmen who discovered metals in the earth and found ways to refine and use them were the ancestors of mining and metallurgical engineers. And the skilled technicians who devised the irrigation systems and created the marvelous buildings of the ancient world were the civil engineers of their time.

Engineering is often defined as making practical application of theoretical science such as physics and mathematics. Many of early branches of engineering were based not on science but on empirical information that depended on observation and experience.

An engineer is the main motive power of the technological progress. He concerns himself with the application of science and technology to satisfy human needs. In his work he is guided by the latest achievements of science and technology. A modern engineer cannot do without knowledge in many fields other than those of engineering. He must get a substantial training in subjects of his speciality as well as in such subjects as computers and robotics, environmental engineering, management science, etc. He must have a scientific attitude, imagination, initiative and good judgement.

The principal work of the engineer is design. Engineers design and make machines, equipment and the like. Such work requires creative ability and a working knowledge of scientific principles. The engineer must also have an understanding of various processes and materials available to him/her and could be working in any of the following areas: the organization of manufacture, research and development, design, construction, sales and education.

The engineer must combine many of the characteristics of the scientist, research engineer and technologist. He must have basic knowledge of the science, and understanding of the abstract techniques of the research engineer and he should know much of the technology employed by technologists.

Unlike the scientist, the engineer is not to solve problems which interest him. He must solve problems as they arise, his solution must satisfy conflicting requirements. Efficiency costs money, safety adds complexity, performance increases weight. The engineering solution is optimum solution, taking into account many factors. It may be cheapest for a given performance, the most reliable for a given weight, the simplest for a given safety, or the most efficient for a given cost.

Exercise 12. Give the Ukrainian equivalents to the following words and word - combinations.

occupation, skill, ancient, forerunners, ancestor, to erect, observation, experience, expansion, design, solution, satisfy, to take into account, reliable, efficient.

Exercise 13. Translate into English.

Інженерне мистецтво, інженер-механік, сучасна цивілізація, розвиватися, практичне застосування, емпірична інформація, виникати, складність, оптимальне рішення.

Exercise 14. Answer the following questions.

1. Is engineering one of the most ancient occupations in history? 2. Whom do we call the forerunners of modern mechanical engineers? 3. Who were the ancestors of mining and metallurgical engineers? 4. What are the oldest branches of engineering? 5. What branches of engineering appeared at the end of the 19^th century? 6. What is the principal work of an engineer? 7. What characteristic features must the engineer combine? 8. Why did you decide to choose the profession of an engineer?

Key dates in science

1769 The Scottish inventor James Watt produced the first version of his improved steam engine.

1774 An English chemist, Joseph Priestley, discovered and isolated oxygen gas.

1783 The first flight in a hot-air balloon took place in Paris, France.

1789Antoine Lavoisier, a French lawyer and scientist, published his Elementary Treatise on Chemistry, which became the basis for modern chemistry.