Ex.1. Agree or disagree:

1. Pollution is the contamination of environment by waste, smoke, chemicals, and other harmful substances.

2. There was no problem of pollution in the Middle Ages.

3. Unsanitary conditions was the main source of pollution in cities of ancient times.

4. The world’s environment is fully contaminated by chemical substances.

5. Plants and animals do not suffer from pollution.

6. A pollutant is a dangerous and harmful substance.

7. The high concentration of a pollutant makes it harmful.

8. Radioactivity in low quantity is useful to life.

9. Countries try to take measures to stop pollution.

10. Pollution is more serious in big cities.

Ex.2. Answer the questions:

1. What is pollution?

2. Where can we see pollution?

3. Is it a new problem? What was the main source of pollution in Middle Ages?

4. What has become more complicated since the Industrial Revolution?

5. What has created pollution problems?

6. Who is exposed to new risks from diseases?

7. Have many species of plants and animals become endangered?

8. What laws have governments passed?

9. What is carbon dioxide?

10. When does human sewage become a serious pollutant?

11. What can human sewage cause?

Ex. 3 Get ready for the dictation.

There are a lot of problems on our planet today. The most serious problem is an ecological one. Ecology is the science that studies the relationships of man, animals, plants and their environment. Environment includes all living things and everything that is not alive, such as soil, air and water. Human activities can make the environment unhealthy. People burn fuels and poison the air. They pollute water and soil with wastes. They cut trees and kill animals and plants. Many scientists study the environment. They want to stop pollution.

Ex.4. Make a written translation of the text “Environment and ecology”.

TEXT 6. THE AIR

Memorize the words and word combinations:

Substance, to breath, oxygen, nitrogen, experiment, laboratory, to add, water vapour, to mix, mixture, reaction, amount, constituent, to condense, to cool, to contaminate, to sort out, ordinary, to combine, evidence, discovery, investigation, density, inert, unreactive

The layer covering all over the Earth like a blanket is called the at­mosphere. It is made of very thin stuff called air. Air is so thin you hardly know it's there. But it's all around us. Really, we live at the bot­tom of a very deep "ocean of air".

Air gets thinner and thinner as you go up. There's enough air to breathe at the top of Mt. Everest (five miles above sea level), but get­ting there is hard work! Most climbers have used breathing apparatus on their way up. By the time you get to 50 miles above sea level, there's practically no air left. The air doesn't stop suddenly, however, so it's impossible to say exactly how deep the atmosphere is.

Air is not a single substance. It's made of a number of gases all mixed together. It's impossible to stop gases mixing together. They mix together spontaneously. So a gas that escapes from the Earth becomes a part of the atmosphere. Scientists believe that the atmosphere has changed a very great deal since the Earth was first formed. At first, the atmosphere may have been made up of gases like ammonia, methane, carbon dioxide and water vapour. Later, the first early forms of life developed and gradually more and more oxygen was added to the atmosphere. Nowadays the main gases in the air are oxygen and nitrogen.

You can easily make experiments in the laboratory to find out about the air, for example, to prove that it's a mixture rather than a single substance, or find out how much oxygen there is in it. These ex­periments usually involve getting the oxygen to combine with another substance. In other words, to get rid of the oxygen altogether a chemi­cal reaction is used.

There are plenty of ways to do this because oxygen is a very reactive gas. For instance, burning and rusting are two lands of chemical change that use up oxygen.

The main gas left after removing oxygen is nitrogen. In fact, nearly all of the remainder (about four-fifths) is nitrogen. To put this another way, 78 percent of the air is nitrogen.

Apart from oxygen and nitrogen, there are only small amounts of other gases in the air. One of them is carbon dioxide. Another of the minor constituents of the air is water vapour. Ordinary air always con­tains some of it. The best way to show that there is water vapour in the air in the laboratory is to condense the water. This can be done by cooling the air. Although there's not much of either water vapour or carbon dioxide in the air, both of them are very important.

So far we've mentioned oxygen, nitrogen, carbon dioxide and wa­ter vapour. Are these the only gases in the air? The answer is "no", but it's hard to prove.

Evidence for other gases in the air came towards the end of the 19^th century (a long time after oxygen and nitrogen had been sorted out). The work leading to their discovery was an investigation into the density of nitrogen.

Unlike oxygen, nitrogen is very unreactive. So it's difficult to make experiments to remove nitrogen from the air. But it's quite easy to take the oxygen, carbon dioxide and water vapour out of the air practically leaving nitrogen alone. This nitrogen might be called "atmospheric ni­trogen".

The main gas that "contaminates" the atmospheric nitrogen is ar­gon. Being a very inert gas, it's used for filling electric light bulbs.

Ex1. Answer the following ques­tions:

1. Why can't you know that there's air around us?

2. Why is it impossible to say how deep the atmosphere is?

3. Why isn't it possible to stop gases mixing together?

4. What was the atmosphere made up at first?

5. What are the main gases in the atmosphere nowadays?

6. What experiments can be made in the laboratory to find out about the air?

7. What can you say about carbon dioxide and its importance?

8. What will you do to show that there is water vapour in the air?

9. Why is it difficult to make experiments for removing nitrogen from the air?

10. What do you know about argon?

Ex. .2. Find English equivalents to the following Russian words and word combinations:

nouns: слой, одеяло, вещество, дно, вершина, уровень, скало­лаз, свидетельство

verbs: упоминать; вести; загрязнять; дышать; улетучиваться; добавить; выяснить; доказать; выделять (изолировать)

adjectives: тонкий; глубокий; перемешанный; обычный

adverbs: вокруг; вдруг точно; стихийно; начало; позже; постепенно; полностью: много; почти: в отличие; около

prepositions and conjunctions: с тех пор как; до сих пор

word combinations: очень сильно; возможно состояла; другими словами; избавиться; наилучший способ; трудно; совер­шенно легко; можно было бы назвать; иначе говоря chemical terms: горение; ржаветь; кислород; азот; аргон; реак­тивный; инертный; углекислый газ; охлаждение; удалить; смесь

Ex.3. Find synonyms:

1.stuff 2. evidence 3. to contaminate 4. to sort out 5. ordinary 6. suddenly 7. exactly 8. spontaneously 9. gradually 10. plenty 11. burning 12. rusting unreactive 14. to remove 15. mixture

a) inert b) usual c) precisely d) testimony e) to delete f) to isolate g) much h) matter i)combustion j) impulsively k) to pollute l) corrosion m) unexpectedly n) amalgam o) little by little

Ex.4. Complete the sentences using the words from the list below. Some of the words can be used more than once:

level, layer, blanket, top, evidence, to mention, to lead, to contaminate, to isolate, nitrogen, oxygen, argon, spontaneously, gradually, to escape, atmosphere, density, bottom

. ... for other gases in the... came towards the end of the 19th century

2. The work... to the discovery was an investigation into the... of… .

3. The ... lying all over the Earth like a... is called the....

4. So far we've … …, … ,carbon dioxide and water vapour.

5. By the time you get to 50 miles above sea ..., there's practically no air left.

6. The main gas that... the atmospheric ... is ...

7. Gases mix together....

8. So a gas that... from the Earth becomes a part of the … .

9. ... more and more … is added to the ....

10. ... and ... were... long before the end of the 19th century

11. We live at the... of a very deep "ocean of air".

12. There's enough air to breathe at the ... of Mt. Everest.

Ex.5. Look through the text again and find all the definitions connected with air.

Ex.6. Look through the text once more and change the given questions to the order of events they occur in the text:

1. What is air?

2. What other gases are there in the air?

3. What is atmosphere?

4. What experiments with air can one make?

5. How deep is the ‘ocean of air’?

Ex.7. Retell the text using the questions from Ex.6 as a plan.

Text 7. AIR POLLUTION.

Memorize the words and expressions:

air, healthy, substance, essential, polluted, to cause harm, atmosphere, fossil fuel, coal, gasoline, automobile, power, particle, carbon monoxide, ozone layer, completely, to affect, to trap, to warn, damage

Clean airis essential to a healthy environment. Air is considered to be polluted when it contains certain substances in amounts high enough and for periods long enough to cause harm. Air can be polluted through such natural causes asvolcaniceruptions and forest fires, which send smoke, ash, and gases into theatmosphere. These types of pollution may have not only local and regional effects but also long-lasting global ones. Nevertheless, only pollution caused by human activities, such as industry and transportation, can be controlled.

Most air pollution comes from the burning of substances called fossil fuels, such as coal and gasoline. Factories and automobiles burn these fuels for power, but they do not burn them completely. The unburned particles from the fuels include solids such as soot and ash as well as gases such as carbon monoxide and ozone. In many places smoke from factories and cars combines with naturally occurring fog to form smog. London, Los Angeles, Tokyo, and Mexico City are among the cities that have faced serious smog problems over the years.

Air pollution may affect humans directly, causing diseases such as cancer, bronchitis, emphysema, and asthma. More indirectly, the effects of air pollution are experienced through gradual change to climates all over the world. For example, the growing use of fossil fuels has led to a buildup of carbon dioxide in the atmosphere. This gas traps heat from the sun at the Earth's surface, causing global temperatures to rise. If allowed to continue, this could eventually cause melting of the polar ice caps, raising of the sea level, and flooding of coastal areas around the world.

Another serious climatic effect of pollution is acid rain. This occurs when certain gases created by burning fossil fuels combine with particles of water in the atmosphere. When these particles fall to the ground as rain or snow, they damage forests, soils, bodies of water, and buildings.

Scientists also have warned about the damage that pollution is doing to the ozone layer of the atmosphere. This layer protects the Earth from harmful radiation from the sun. If the ozone layer becomes too thin or disappears, this radiation could reach the Earth. It could cause crop failures, the spread of diseases such as skin cancer, and other disasters.

Glossary: