Around the sun leaving a bright trail behind. For more than

Thus, all nations should make an attempt to stop pollution. At the present time, it seems more likely that man's future will be determined by his success or failure in preserving a healthy environment than by a worldwide famine, disease or war.
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RECYCLING WASTE

The amount of garbage produced each day is growing at an alarming rate. Many big cities all over the world face a crisis because they are running out of space to dump wastes.

One of the solutions to this problem is recycling, that is, reusing materials. Years ago, milk bottles, beer bottles, and soft drink bottles were reused repeatedly; and many drink companies offered deposits for their bottles to encourage the public to return them. With the increasing use of inexpensive tin cans and plastic containers, however, glass returnables became less and less popular despite the slight effort that was required to return them.

When waste disposal became a problem, interest in recycling was revived. Companies began to promote their returnable bottles (which had never completely disappeared from the market) once again. In addition, a new 'recycling industry' sprang up, and the term 'recycling' took on a new meaning: it meant not only reusing a finished product such as a bottle but also breaking down glass bottles and paper products from the old. Recycling centers, where people can bring their empty bottles and old papers, have been set up in both small and large towns in many industialised countries.
134

OCEANS
Nations, as well as individuals, have always used the oceans - for fishing, trade, and pleasure - with little concern for anyone else's fights. The oceans used to be large enough for Everyone. As the world has grown 'smaller' through improved communications and transportation and increased population growth, the oceans have become more crowded. It is now possible for a nation to go far from its coasts to fish and wade, and each year many of the new nations develop fishing and wading fleets. Instead of the large empty ocean that once existed, it is now filled with many people who are interested in using its resources. This results in strong competition among nations. Since each nation has different needs and aims, problems Eventually arise.

Nations are beginning to realize that laws must be established to protect the resources in the oceans - its fish and animals, its plant life, and its minerals. However, due to the long practice of free use of the oceans, it is difficult for man to accept the need for these laws.
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SURGERY
In early years of this century there was little specialization in surgery, i.e. cutting into a part of the body. A good surgeon was capable of performing almost every operation that had been devised up to that time. Today, the situation is different. Operations that were not even dreamed of fifty years ago are now being carried out. The heart can be safely opened and its valves repaired. Clogged blood vessels can be cleaned out, and broken ones mended or replaced. A lung, the whole stomach, or even part of the brain can be removed and still allow the patient to live a comfortable and satisfactory life. However, not every surgeon wants to, or is qualified to carry out every type of modern operation.

The boundaries of surgery have widened remarkably in this century. Its safety has increased too. Deaths from most operations are about 23% of what they were in 1910 and surgery has extended in many directions, for example to certain types of birth defects in newborn babies and, at the other end of the scale, to life-saving operations for old people. The hospital stay after surgery has been shortened to as little as a week for most major operations. Most patients are out of bed the day after an operation and may be back at work in two or three weeks.
136

ULTRASONICS

Some of the world's most interesting and useful sounds cannot be heard at all. Ultrasonics - the 'too-high-to-hear sounds' - can be used to drill, cut weld, clean, and inspect for cracks and flaws. Like all sounds, they travel in waves through the air or any other medium, but they have a far higher frequency than the sounds we hear.

Human ears can detect sound waves that vibrate from 20 to 20,000 times per second. Bats can hear up to 50,000 vibrations per second. But when scientists talk about ultrasonics they can mean billions of vibrations per second.

Special vibrators produce these high-frequency sounds. One, the transducer, is made by sandwiching a thin slice of quartz crystal between two metal plates and passing an electric current through it. When this happens, the crystal expands and contracts by a tiny amount - but enough to generate the pressure waves needed. Ordinary sound waves spread in all directions, but because of their high frequency, ultrasonics can be more easily directed into a beam and made to do useful work.

They can be used to detect invisible cracks in metal because the sound waves travel at a different speed through the crack than through the metal. Dishes and clothes can be washed with them because of the pulsations they set up in liquid.

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DESERT PLANTS

Only specialized plants can survive the climate of a desert because deserts are regions with very little rainfall. The entire yearly rainfall occurs during a few days or weeks in spring. For the remaining ten or eleven months of the year, desert plants must survive without rain.

There are two types of desert plants: annuals and perennials. Desert annuals, such as grasses and flowers, survive from one year to the next by existing through the long, hot, dry season in the form of seeds These seeds remain inactive if the right amount of rain does not fall. If there isn't enough rain, they wait Until the following year or even the next. Another factor that helps these plants to survive is the fact that their life cycles are short. If they get the right amount of rainfall, the seeds grow into plants which flower, then form new seeds and finally die, all in just a few days or weeks. By the time the water from the spring rains disappears - just a few weeks after it falls - the desert annuals don't need any.

Desert perennials also have special characteristics which enable them to survive as plants for several years. Nearly all perennials have a well-developed root system below ground (which enables the plant to absorb the maximum amount of water possible in a short time) and a comparatively small shoot system, that is, leaves and branches (which limits water loss).

Another characteristic of many desert perennials is their deciduous habit; that is, after the rainy season they lose their leaves to prepare for the long, dry season, just as trees in wetter climates lose theirs to prepare for the winter. This reduces their water loss during the dry season to a minimum. Then, in the next rainy season they come fully alive once more, and grow new branches, leaves and flowers, just as the desert annuals do.

138

AMARANTH
Amaranth is a kind of high-protein grain. It may easily be grown in many areas which are unable to support other crops. Agriculturalists think it is a promising crop which may help feed a hungry population in the future.

It is not a new idea to grow amaranth as a foodstuff. In Mexico during the sixteenth century, the Aztecs cultivated it. The plant was an important part of their diet. It has been shown that the Aztecs harvested close to 6,000 metric tons of the grain each year. However, when Cortes and his Spanish army invaded Mexico, they destroyed the crop completely. Today only a few wild and uncultivated kinds of amaranth exist, and it is rarely used as food in Mexico.

It has been discovered that amaranth is a highly nutritious foode The plant's seed is high in protein, and it contains an important amino acid called lysine. Amino acids are organic compounds that are the building blocks of protein. Lysine is an essential amino acid that is missing in wheat, nce, and corn. The leaves of some varieties compare in taste and nutritional value with spinach and other vegetable greens.

Amaranth can be ground into flour and made into baked foods. Bread made from amaranth flour is heavy and very compact when compared with the light and airy bread common in North America. The flour can also be used for cakes, cookies, and crackers, as well as high-protein breakfast cereals and snack foods.

It is true that breeding a wild plant into a major food crop such as wheat requires much research time. Agriculturalists know that it has taken hundreds of years of breeding different varieties of corn to get the better kinds we have today. They have to go through the same time-consuming stages to grow amaranth as a crop. Presently there are several problems. Because it is a wild plant, it is hard to predict the date when the crop will be ready to be harvested. It is also impossible to know the expected height of the individual plants or how much a given amount of seed can produce. It is important, for economic reasons, to breed a plant of standard height and one that can be harvested at a specific time each year.

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139

DREAMS
Dreams have always held a universal attraction. A lot has been said and written about them. Although most dreams happen spontaneously, dream activity may be stimulated by external influences. 'Suffocation' dreams are connected with the breathing difficulties of a heavy cold, for instance. Internal disorders such as indigestion can cause vivid dreams, and dreams of racing fire-engines may be caused by the ringing of an alarm bell.

Experiments have been carried out to investigate the connection between deliberately inflicted pain and dreaming. For example, a sleeper hurt slightly with a pin perhaps dreams of fighting and receiving a serious wound. Although the dream is stimulated by the physical discomfort, the actual events of the dream depend on the associations of the discomfort in the mind of the sleeper.

A dreamer's eyes often move rapidly from side to side. Since peop!e born blind do not dream visually and do not show this eye activity, it is thought that the dreamer may be scanning the scene in his dream. A certain amount of dreaming seems to be a human requirement - if a sleeper is woken up every time his eyes begin to move fast, effectively depriving him of his dreams, he will make more eye movements the following night.

Of the many theories of dreams, Freud's is probably the best known. According to Freud, in our dreams, we return to the modes of thought characteristic of early childhood. Our thinking becomes pictorial and non-logical and expresses ideas and wishes hidden deep in our minds.
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POLLUTION (2)

Ecology means the study of the inter-relationships of plants, animals, human beings and their environments. Environment is Everything that affects the quality of your life: the air you breathe, the water you drink or swim in, your flat or house, the number of people, the traffic, the noise and streets, shops, parks, countryside, seaside, factories, farming, mining.

The different kinds of pollution are all connected. What happens to the air affects the land. What happens to the land affects the water. And what happens to the water affects the am

Man has been polluting the earth for a very long time. At first, when the environment got dirty, people moved to a cleaner place, but the rise in population and the developing industry have changed that, and we can't do it any more. There are new kinds of waste, such as plastics, and new chemicals which are very hard to destroy. So, the

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earth is becoming dirtier.

Every year about 150,000,000 tons of dirt, sprays and gases go into the air over the USA. Air pollution damages paint and metal, makes our clothes dirty, stops the growth of plants and can also cause many diseases and death. There are two main causes of air pollution: fumes from cars, trucks and buses, and fumes from industry. In large cities, cars alone are responsible for about 80 per cent of the air pollution. Gasoline engines give off a gas called carbon monoxide, which has no colour or smell. This gas will make you sleepy, give you a headache and can finally kill you. Scientists say that breathing the air of New York is like smoking forty cigarettes a day.

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THE ELECTRIC EEL

There are a number of different kinds of electric fish living in the various rivers and oceans of the world. They can generate electricity up to several hundred volts. The most powerful electric fish are the electric catfish and the electric eel.

The electric eel lives in South America. Its special organs can generate a very powerful electric current, which is enough to light twelve light bulbs. The eel uses this electric charge to kill its prey -mainly fish and frogs - and to keep its enemies away.

The electric eel manufactures the electric current in its tail, where thousands of cells are linked together and form a kind of 'charging' machine. The electric shock from the eel lasts only a fraction of a second.

Electric eels can sometimes be nearly two meters long. As they move through the water, they send out weak electrical charges and these create an electric field around them. These charges help jkrfl to locate their prey when some other sea animals enter the electrical field and cause a change in the current impulses.

142

SMOKING
There is some disagreement on whether Sir Walter Raleigh, the 16th century adventurer and explorer, introduced tobacco into Europe, or only popularised the habit of smoking. Either way, he was not aware of the harm he was doing to future generations.

Smoking, of course, was not always as popular as it is today. It was mostly men who smoked, and it was considered a slightly dirty and unpleasant habit. After dinner, the men would 'go' to the 'smoking room in their 'smoking jackets' before lighting their cigars and pipes. Cigarettes are relatively recent and they have become more available (as with so many other things) by the arrival of mass production. By the First World War, smoking had left the 'smoking room' and had joined the people. This popularity of the cigarette continued in the inter-war years. By that time, the relaxing qualities of cigarettes had been known and to this Hollywood added another attraction. With a cigarette dangling from your lips, you too could be like Humphrey Bogart, or James Cagney, or Betty Grable - or - whoever your idea of the

attractive film star was. It is funny that the act of smoking dried leaves could be considered to make you look better but so it was. The young people in the 1930's and 1940's first took up smoking as a mass habit. This was the period when the pressures of living first began to be so great that people needed the relaxing qualities of nicotine.

It was not Until much more recently, however, - within the last ten or twenty years - that we have realised what has happened to us. We no longer smoke for the purpose of relaxation, or after-dinner social enjoyment; today's smoker lights a cigarette over his breakfast coffee, continues throughout the day, and puts out his last cigarette just before he turns off the light at night. He smokes as if his life depends on it -but he knows that his life may depend on his not smoking. The connections between lung cancer, rapidly becoming one of the largest killers in modern society, and smoking have been demonstrated, but we still cannot give up. Governments are beginning to take action against smoking - but without too much interest, for tobacco is one ₉f the most profitable sources of tax. The British Government toorthe enormous step of ordering the cigarette manufacturers to print a warning that "Smoking Can Damage Your Health" on the side of all cigarette packets. The only effect of this is that smokers need a few extra cigarettes to further relax their terrified nerves.

Do you smoke? Can you run for the bus without being short of breath? Can you smell the flowers in spring? Is your house full of

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finished and half-finished cigarettes? Do you spend the first ten minutes of every morning coughing?

Look, I've got an idea. Let's give up smoking. Well, anyway... let's give it up tomorrow

Oh, Walter Raleigh! What have you done to us?

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DDT
It is clear that some chemicals can damage the health of animals and humans. However, this is not the only problem that can be caused by the careless use of chemicals. Chemicals can also disturb the ecological balance of the environment. If the ecological balance is disturbed, the consequences can be extremely serious.

The history of DDT illustrates this problem. DDT, a chemical which kills insects, at first seemed to be a perfect answer to many problems. It would control insects that caused dangerous diseases, as well as insects that caused billions of dollars of damage to crops every year. Governments permitted and even encouraged the use of DDT. Farmers in many countries began to spray it on their crops. The immediate results were good: damage to crops went down, and profits went up. However, the chemical had effects which the scientists had not predicted. First, it also killed insects which were the natural enemies of the harmful insects and which were, therefore, beneficial to farmers. Second, and perhaps worse, DDT did not kill every harmful insect. A few insects, which had natural resistance to the chemical, survived and multiplied. In a few years, there were large numbers of insects which were not affected by DDT, and there were fewer insects which could act as natural controls on these new 'Super-insects'. Finally, it became clear that DDT was not solving the insect problem. In fact, it was making the problem worse. It then became necessary to find a second cure for the effects of the first!

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144

DRY FOOD
Food contains proteins, carbohydrates, fats and vitamins and these are vital to life. Food must be fresh when we eat it. If it is bad, it can make us ill. There are two main agents which turn food bad; fungi (such as yeast and various moulds) and bacteria. These are micro-organisms which cannot make their own food. So they live and grow on our food. Moulds, for example, usually grow on bread. Yeast can spoil fresh food but it also has some very useful properties. For hundreds of years people have used it in the making of bread and wine.

In order to grow and multiply, all these micro-organisms need food, water, warmth and, in some cases, air. The methods we use to preserve our food make conditions dry and very cold; unsuitable for the growth and multiplication of micro-organisms.

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The great distances which often separate the producer of food from the consumer in the 20th century make effective food preservation vital. But most preservation processes destroy many important vitamins and proteins. One of the tasks of food technologists today is to find ways of preserving food without losing these important substances.

In hot countries people dry food simply by the heat of the sun. In this way, it is possible to reduce the moisture level in most fruits to between 5% and 15%. This level is low enough to stop the growth of micro-organisms. Some other kinds of food go through a process called dehydration. In this process, hot and dry air passes over the food and absorbs as much moisture as possible. This method is usually used for drying tea and coffee. Another way of preserving food is putting it into cans or bottles and heating it up to a temperature of 100⁰C or 120⁰C for about ten minutes because high temperatures kill micro-organisms in food.

There are several other ways of preserving food. One of them is freezing the food to a temperature between -30⁰C and -40⁰C. Some people still use two very old methods: salting and smoking. Salt stops the growth of micro-organisms and smoking removes some of the moisture in the food.

Certain acids and chemicals are useful preservers because they stop the action of micro-organisms. For example, we can use vinegar, an acidic liquid, to preserve eggs, onions and some vegetables. One of the newest methods is radiation. It is very effective because it kills not only the micro-organisms but also their spores (small cells which fungi or other micro-organisms produce in order to reproduce the organism). In this way, it stops their reproduction.
145

BLUE-JEANS

It has been more than 130 years since Levi Strauss invented blue-jeans and they are still very popular today. Farmers and workers wear them to work in; children wear them to play in. Others wear them because they are comfortable. Before the 1950's, blue-jeans were popular only in the West and Southwest. Today, almost Everyone wears them. Americans buy about 500 million pairs of jeans a year. That's more than two pairs per person. Of course, blue-jeans are also popular in other parts of the world. In these areas, people buy about 200 million pairs of jeans.

Levi Strauss and Company makes about one-third of all the jeans in the United States and about one-seventh of those in other countries. In fact, for a long time, people used the word 'Levi's' as a synonym for blue-jeans. That's because 'Levi's' were the first jeans. The inventor was a German immigrant named Levi Strauss.

Levi Strauss left Germany in 1848, when he was a young man. He came to New York City to be near his two brothers. For two years, he worked as a salesman. He worked hard, but he didn't earn much money. Then, he decided to go to San Francisco. Gold was discovered in California in 1848, so many people left their homes and jobs in the east and they moved to mining camps in California, hoping to find gold and become rich. Some of them did, but many did not.

When Levi went West, he brought some canvas (a very strong cloth) with him. He wanted to sell it to the miners for making tents. His canvas was the wrong kind for tents, so nobody bought it, but Levi found another use for it. A miner told Levi that he needed a good, strong pair of pants because digging for gold was hard work. When Levi heard that, he made a pair of canvas pants for the miner The miner paid Levi 6 dollars in gold dust and told the other miners about 'those pants of Levi 5. Levi quickly sold a lot of pants, so be wrote to his brothers in New York and told them to send him more canvas, but they sent him some heavy cotton cloth called 'denim', much of which came from Genes (the French name for the city of Genoa, Italy). Levi changed the spelling of Genes to jeans'. He called his new pants blue-jeans.

In 1853, Levi and his brothers opened a small clothing business in San Francisco. Today they make and sell about 250 million pieces of clothing a year - from women's clothes to men's suits, and of course, blue-jeans.

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THE REBIRTH OF THE FEMINIST MOVEMENT
There is a popular belief that the feminist movement, which became very popular and powerful in the early 1970's, caused women to be dissatisfied with their traditional roles as wives, mothers, and homemakers. These women then began to find more satisfying work outside the home. This, however, is not an accurate picture of the connection between working women and the feminist movement. Although feminism, or women's liberation, has been an important factor in the changes which have occurred in the role of women since 1970, jj did not begin these changes.

There are two primary causes for the increase in the number of American women who work outside the home. First, between the end of World War II and the early 1960's, the population of the country was growing rapidly, and this growth created a need for more teachers, more medical assistants and nurses, more social workers, more secretaries, and more store assistants. Therefore, a large number of jobs became available in service industries. These types of occupations had two important features in common: (1) they were jobs which were already traditionally held by women, and (2) in comparison with jobs which were traditionally held by men, they were poorly paid. They were, therefore, jobs that did not usually attract men.

The availability of new jobs that men did not want, however, is not by itself an adequate explanation for the rise in the number of working women. it does not answer the question of why women wanted to work. The second cause of the increase in the number of working women is the economic pressures which forced married women, especially young married women, to look for work outside the home. In the 1960's, people in the U.S. began to expect a higher standard of living; they wanted the expensive consumer goods that U.S. industry was producing. However, often the husband's earnings did not permit the family to buy the new kitchen appliances, the color television, the new clothes, the furniture, and the second automobile which seemed so necessary. It became necessary for wives to increase the famfly^ts income, and so women began to take the service jobs that were becoming available.

It is clear, therefore, that the increase in the number of working women began before the feminist movement was reborn in the late 1960's. In fact, many experts argue that the increase created the modern feminist movement. Working women were the cause, not the

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result, of women's liberation. According to these experts, economic conditions and the experiences of these working women were the main factors in the development of the feminist movement in the 1970's.

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COOPERATIVE EDUCATION

'Cooperative education' is a significant innovation in university education programs and ft has found increasing favor in recent years. Cooperative education makes full-time work in industry, business, or government a pan of the program. Thus, by alternating semesters of study with work related to that study, 'co-op' students receive valuable job training while earning money for tuition. The program makes advanced schooling more meaningful and realistic.

Universities like the idea of cooperative education, not only for its educational value but also because such programs aid them in expanding enrollments. With a large number of students spending time away from school working, universities can accept more students without increasing the number of buildings and teaching staff. The business community welcomes the well-trained employees into jobs before and after graduation.

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THE EGYPTIAN PYRAMIDS

The ancient Egyptian civilization, famous for its mighty pyramids, lasted for more than 3000 years. During this time Egypt was ruled by about at least 30 dynasties, ruling families of kings or queens. The pyramids were constructed as tombs, i.e., as burial places for the Egyptian kings and their families. Originally, during the First and Second Dynasties, which lasted Until about 2665 B.C., kings of Egypt constructed a type of tomb called 'the mastaba'. A mastaba looked like a low, rectangular shoebox.

The first typical pyramid was built in 2650 B.C. during the Third Dynasty. This pyramid was built for King Zoser by an architect named Imhotep as a series of giant steps or stairs. It, along with the others of its type, is called the Step Pyramid. It was really simply a pile of steps each higher and smaller than the one before. The Step Pyramid of King Zoser was different from the later pyramids because it was never covered with stone to give it a smooth surface.