Around the sun leaving a bright trail behind. For more than
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80 DISTILLING OIL When plants and animals die, they normally decay, helped along by fungi and bacteria in the environment. Once decomposed, L&)ch provide nutrients for living organisms, and the respiration of fungi and bacteria causing decay releases carbon dioxide into the atmosphere. Over a period of several hundred million years, however, comparatively small amounts of organic material have remained under layers of silt, soil or volcanic rock and, as there is no oxygen, have not fully decomposed. Instead, they have formed deposits of coal, natural gas and oil, often located far below the land surface or the sea-bed. Oil is usually found in porous rock under a layer of hard rock which prevents it from escaping. It can, then, only be reached by drilling. The initial rush of oil out of a drill pipe is caused by the pressure of the gas compressed immediately above the oil deposits. In time, this pressure decreases and the oil has to be' pumped to the surface. Raising oil from below the sea-bed is an immensely difficult and dangerous operation. Although drilling engineers are exposed to high winds and heavy seas, they have to make test bores to see if it is worth exploring further. After they are satisfied that they have found an oifield, they set up a platform. The quality of the oil which is piped up to the surface varies, but it all has to be brought ashore. This is done either by pumping it along pipelines or carrying it in tankers. In the North Sea, as they are constantly threatened by the weather, the big oil companies have, on the whole, preferred pipelines. In other locations, where they are favoured by better weather conditions, they often use tankers. The crude oil raised directly from wells is not yet ready for use. It has to be refined. The first stage in this process is fractional distillation in a fractionating column. Those fractions, such as petrol and kerosene, which are lighter and more volatile, move towards the top of the column before condensing. The heavy residual fuel at the base of the column is extremely impure. The fractional distillation of crude oil results in the production of several useful substances, all of them normally liquids except the gas from the top of the column and the solid residue at the base. Straight petrol, which vaporizes between 300 and 2000 Centigrade, is used (when mixed with petrol produced from kerosene and heavy gas oil) as fuel for motor cars. The gas, which boils between 200 and 1 640C, also has a use - many households rely on it for heating and cooking.Kerosene has, of course, become invaluable as the fuel consumed by jet planes. It boils between 2000 and 3000C, whereas heavy gas oil and fuel oil vaporize within the range 3000C. The former is used to produce diesel fuel for lorries, buses and some cars, and the latter is redistilled to produce other fractions. The heavier fractions, such as petroleum jelly and paraffin, The former with a boiling point over 3500C and the latter with a melting point between 520 and 570C, have a variety of uses1 Petroleum jelly is a useful lubricant and is used on the skin, and paraffin is the main component of wax candles. The pitch and tar at the bottom of the column, which boil at over 4300C, are used to make asphalt. So, there is little wastage. But distillation does not produce enough high grade petrol to meet today's high demand. The petrol offered for sale to motorists is a mixture of straight petrol and distilled petrol produced by chemical modification from certain other distillates.
81 PATTERNS OF OCEAN LIFE A striking example of how man can drastically alter the interdependence patterns of ocean life has occurred off the coasts of southern California. In the nineteenth century, these waters had a large population of that busy little animal called the sea otter, which ate sea urchins*, which, in turn, fed on large brown algae called kelp. Sea otters almost totally disappeared due to fur traders who encouraged hunters to kill off otters for their valuable furs. With the disappearence of the otter, sea urchins started to reproduce in vast numbers, leading to a great increase in their population. This caused sea urchins to almost entirely exhaust kelp beds. At this point, man had replaced the original balance of nature with a new pattern: The sea urchins, which previously had been the prey of the sea otter, had become the predator* and the kelp had become the new prey. As the kelp began to disappear, sea urchins began to starve. With the reduction of the urchin population, the kelp managed to reproduce and increase their numbers. Yet, the sea urchins again increased and so on. A cycle taking from 10 to 12 years started to repeat itself. A further step came when sewage pollution caused an additional destruction of kelp - not because sewage kills kelp but because sewage feeds sea urchins, which once again increased in numbers with this new source of food. If sea otters had been present in sufficient quantities, the kelp beds would still be abundant. In order to re-establish the proper balance in the eco-system, marine biologists have put forward a number of solutions. In time and with the help of man, nature may regain its previous order.
82 GROWING UP When we are young, the house where we live is our whole world. Everything is provided for us - food and shelter, warmth and love. We obey our parents without question, because if mummy and daddy say it, it must be right. Every experience we have is classified as good or bad according to their reaction. We quickly learn to do those things which earn their praise, and to avoid doing those things which upset them and earn their disapproval. As we grow older, we are more and more exposed to outside influences - school, friends and other adults. We soon start to realise that there are other values which are different from those our parents hold. For example, your parents have told you that some words, such as ~bl~yt~ are swear words, and they have forbidden you to use them.in your friend's house, Everyone - children and grown-ups -says things like 'Bloody hell!' when they are annoyed and no-one seems to think that there is anything wrong with it. You are confused; you wonder what the right thing to do is. You try to resolve the conflict of values between two groups of people - your parents on the one hand, and your friend's parents on the other - for whom you have equal respect. Eventually what happens is that we start to lead double lives; we reserve some forms of behaviour for the home, and others for the world outside the home. The real conflict starts when we reach adolescence. We begin to question Everything and Everyone, including our parents and their values, because we want to establish our own independent values. Unfortunately, as long as we are living at home and are dependent on our parents, we cannot lead our own lives according to our own views of right and wrong. The trouble is that if our parents give us more freedom, we are bound to make mistakes, and they will wonder if they have given us too much freedom. On the other hand, if parents allow too little freedom, their teenage children are likely to become resentful and rebellious. Somewhere between the two extremes, it ought to be possible to find a sort of 'democratic' alternative, which allows children the freedom to büyümek. 2. meydana gelmek, vuku bulmak grow up and to make their own decisions, including mistakes, but which also offers them help and protection when they need it.
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