Branches of Chemistry. Organic Chemistry

In an achievement regarded as a milestone in synthetic organic chem­istry, two research groups in 1994 announced development of techniques for the total synthesis of the anticancer drug taxol. Originally isolated from the Pacific yew tree, taxol was regarded as a promising treatment for a variety of cancers, including those of the ovary, breast, and lung. At first, obtaining taxol in quantity had been expected to require the cutting and processing of thousands of trees, leading to concern about destruction of yew forests. The shortage in supply set off a worldwide race among organic chemists to obtain the molecule from other sources, yet its total synthesis from simple starting materials proved to be one of the most elusive goals of the past decade. The taxol molecule is large and complex, built from an unusual system of four rings extremely difficult to recreate in the laboratory.

The two techniques to taxol synthesis are different and were devel­oped by separate research groups. Robert A. Holton and co-workers of Florida State University used ordinary camphor as a starting material and proceeded with a " linear" strategy to assemble each component of the molecule one piece after another. By contrast, K.C. Nicolaou and co-workers of the Scripps Research Institute, La Jolla, Calif., and the University of California at San Diego used a " convergent" strategy in which two large parts of the taxol molecule are synthesized separately, and then joined.

Neither synthesis was expected to have an immediate impact on the commercial supply of taxol, which no longer was scarce. Taxol was be­ing made in a semi-synthetic process from chemical precursors collected from yew needles and twigs, which can be harvested without killing trees. But scientists said that the work could have the way for a simpler total synthesis and that it had expanded knowledge about synthesizing com­plex molecular structures.

Natural gas, best known as a fuel for home heating and cooking, is typically 85-90% methane (CH₄). Researchers long have sought cheaper and better ways for exploiting the methane in natural gas as a raw mate­rial for making industrial chemicals that currently must be made from petroleum. Doing so has proved difficult because methane does not readily undergo the proper chemical reactions.

During the year AyusmanSen and Minren Lin of Pennsylvania State University reported developing a single-step process that converts meth­ane into acetic acid (CH₃COOH) under mild conditions. An addition to, being the acid in vinegar, acetic acid is a key raw material of the chemical industry, used in the manufacture of plastics, Pharmaceuticals, pesticides, dyes, and other products. Most industrial acetic acids has been obtained from petroleum. Sen and Lin's process requires only methane, carbon monoxide (CO), oxygen (O₂), and a catalyst, rhodium chloride (RhCl₃), which is dissolved in water to promote the conversion of methane. The reaction, which can be summarized as gives high yields and produces only methanol and formic acid as by­products. Importantly, the reactions require temperatures of only 100°C (212°F), the boiling point of water. By contrast, a process used for manufacturing acetic acid from methane requires three costly steps, consumes much energy, and requires hazardous organic solvents that must be con­tained or recycled. The researches regarded the new process as an impor­tant first step toward exploiting the methane in natural gas.

Chemists were devoting increased research attention to molecular self-assembly, a phenomenon in which complex molecules form sponta­neously from simple components. Some scientists suggested that life on Earth originated in such a way, with simple chemical components spon­taneously growing more complex and developing the ability to replicate. In an advance in the understanding of self-assembly, chemists at the University of Birmingham, England, announced discovery of a mole­cule that pieces itself together in a previously unrecognized way. J. Fraser Stoddart and David Amabilino synthesized the new molecule, which was dubbed olympiadane because its five underlinked molecular rings resemble the logo of the Olympic Games. Many organic compounds are formed from ringlike arrays of atoms that are attached by chemical bonds between atoms. Olympiadane's rings, however, are interlocked mechan­ically without bonds. Stoddart and Amabilino encouraged the self-as­sembly by careful control of temperature, pressure, and other conditions during synthesis. During assembly, chains of atoms thread together one inside the other, much like the links on a chain, ending with five inter­locked rings.

Bleach additives in laundry detergent powders work by oxidizing fabric stains through the action of hydrogen peroxide. Laundry deter­gents usually contain a berborate compound that forms hydrogen per­oxide when the detergent powder comes into contact with water. Hy­drogen peroxide, even when aided by detergent additives that lower the water temperature needed for acceptable bleaching activity, does not bleach effectively unless the water temperature is above 40°C (104°F). Many consumers, however, want to do laundry in cooler wa­ter in order to conserve energy and avoid damaging modern fabrics. Chemists thus have searched for low-temperature oxidants that bleach in cooler water.

 

Ответьте на вопросы по тексту:

1. What did two research groups announce in 1994?

2. What was regarded as a promising treatment for a variety of cancers?

3. What is natural gas?

4. What did AyusmanSen and Minren Lin of Pennsylvania State University report?

5. What is the most industrial acetic acids obtain from?

6. What kind of discovery was announced at the university of Birmingham?

7. Why do many consumers want to do laundry in cooler water?

Вариант 5

Текст 1

Genetics

Genetics, the study of heredity in general and of genes in particular.

Although the influence of heredity has been recognized since prehis­toric times, scientific understanding of inheritance is a fairly recent event. Modern genetics began with the work of Gregor Mendel, an Austrian monk whose breeding experiments with garden peas led him to iormu late the basic laws of heredity. Mendel concluded that his plants inherit­ed two factors (one from each parent) for each of the hereditary traits he studied. He further deduced that these factors do not mix in the off­spring, that some factors are dominant over others, and that a parent plant randomly transmits one factor from each pair to an offspring.

Mendel published his findings in 1866, but his discoveries were not appreciated by the scientists of his day. By the turn of the century, how­ever, the intellectual climate had changed; in 1900 a number of research­ers independently rediscovered Mendel's work and grasped its signifi­cance.

The infant science of genetics flowered rapidly. By 1902 Walter Sut-ton of the United States had proposed that chromosomes - major com­ponents of the cell nucleus - were the site of Mendel's hereditary factors. The Hardy-Weinberg law, which established the mathematical basis for studying heredity in populations, was independently formulated by the English mathematician Godfrey H. Hardy and the German physician Wilhelm Weinberg in 1908. In 1910 the American genetist Thomas Hunt Morgan began his studies with the fruit fly, Drosophila melanogaster. Morgan provided evidence not only that genes (as Mendel's factors had come to be called) occur on chromosomes but that those genes lying close together on the same chromosome form linkage groups that tend to be inherited together. He further showed that linkage groups often break apart naturally as a result of a phenomenon called crossing over. During the 1940s, George W. Beadle and Edward L. Tatum of the United States demonstrated that genes exert their influence by directing the production of enzymes, proteins that facilitate chemical reactions in the cell. By 1944 Oswald T. Avery had shown that deoxyribonucelic acid (DNA) was the chromosome component that carried genetic informa­tion. About this time Barbara McClintock discovered mobile plant genes that affect heredity. The molecular structure of DNA, however, was not deduced until 1953 by James D. Watson of the United States and Fran­cis H.C. Crick of Great Britain. By 1961 the French genetists Francois Jacob and Jacques Monod had developed a model for the process by which DNA directs protein synthesis in bacterial cells. These develop­ments led to the deciphering of the genetic code of the DNA molecule, which in turn made possible the recombinant DNA techniques that hold immense potential for genetic engineering (q. v.)

Modern genetics studies include population genetics (the study of genetic patterns within populations), classical genetics (how traits are I mnsmitted and expressed), cytogenetics (the mechanics of heredity within the cell), microbial genetics (the heredity of microorganisms), and mo­lecular genetics (the molecular study of genes and related structures). To some extent, these divisions are artificial; every field overlaps with other genetic fields, and all have implications for the other biological sciences.

Genetics has been applied to the diagnosis, prevention, and treat­ment of hereditary diseases; to the breeding of plants and animals; and to the development of industrial processes that utilize microorganisms.

The Lab between the Stars.

In space, where a hydrogen atom might fly for a million years before finding a soul mate, the opportunities for significant chemistry might appear a little on the limited side. Nothing could be further from the truth. The Universe is a big place and one thing which is not in short supply is time. Most chemistry, despite the impression that is given to students by university courses, occurs not on Earth but in the yawning chasm between the stars. There is mode alcohol, for instance, in the aver­age molecular gas cloud than has ever been distilled in the entire history of the human race.

Granted, " astrochemistry" may not be quite as complex as Earthbound chemistry, whether in the laboratory, industry or living organisms. Never­theless, it is far more intricate than anyone would have guessed even a few decades ago. It embraces esoteric processes, the likes of which are never seen in the high-density environment on Earth. Furthermore, astrochem­istry actually orchestrates a great deal of what goes on in the Universe, which is precisely what is detailed in The Chemically Controlled Cosmosby Thomas Hartquist of the Max Planck Institute for Extraterrestrial Physic in Munich and David Williams of University College London.

Molecules form, the authors tell us, whenever the temperature of matter falls below 3000°C. And since most of the Universe is either colder than this, or has been colder than this at least once since the big bang, molecules have been a ubiquitous feature of the cosmos through­out most of its history. The first time the temperature dipped beneath 3000°C, say Hartquist and Williams, was in the rapidly expanding fire­ball of the big bang about a million years after the moment of creation. Chemistry in this remote epoch was rudimentary because very few elements heavier than hydrogen and helium were forged in the fiery furnace of the big bang. Nevertheless, molecular hydrogen played a crucial role in cooling the cores of giant gas clouds so that they could shrink under their own gravity.

Without its ability to radiate away heat generated during the proc­ess, say Hartquist and Williams, pressure from the hot gas would have prevented galaxies like our own Milky Way from congealing from the stuff of the big bang. Molecules have the ability to remove heat from a gas because when they collide with each other some of their energy of motion is inevitably converted into internal energy. This energy can later be shed in the form of photons.

A molecule can be thought of as a collection of balls connected by springs. The whole structure can vibrate and rotate and, when it is buffeted by other molecules, can be made to vibrate or rotate even faster. Because the laws of quantum mechanics permit only certain rates of vibration and rotation, when the molecule sheds energy by emitting photons it does so at only certain characteristic wavelengths, usually in the infrared of millimetre wave region of the spectrum. For instance, carbon monoxide, the most abundant molecule in space after molecu­lar hydrogen, emits a characteristic spectral " line" at a wavelength of 2-6 millimetres.

So far, astronomers have detected the characteristic spectral signa­tures of almost 100 different interstellar molecules and radicals. And this number does not include variant forms of many of these molecules in which a relatively rare isotope, such as deuterium, substitutes for a more common one like hydrogen.

Astronomers have found the carbon monoxide molecule, for ex­ample. It has been detected in interstellar clouds with all possible com­binations of not only carbon-12 and carbon-13 but also oxygen-16, xygen-17 and oxygen-18. Each of the six separate forms of carbon monoxide exhibits the slightly different masses of its constituent at­oms.

In space, you can find methanol in literally astronomical quanti­ties. It is so dilute that in even the densest molecular clouds it would be necessary to sift through cubic kilometres of space to fill a single glass.

The simple amino acid glycine exists in space as well. It was discov­ered two years ago in Sagittarius B2, the giant molecular cloud at the heart of our Galaxy in which virtually every known space molecule has been found at one time or another.

 

Ответьте на вопросы по тексту:

1. What is Genetics?

2. When did modern genetics begin?

3. Who formulated the basic laws of heredity?

4. How many branches do modern genetics studies include?

5. What are they?

6. What is the difference between chemistry and astronomy?

7. What is astrochemistry?

 

Текст 2

Plastics

The first synthetic plastic was made in the 1860s. Before that, nat­ural materials such as ivory and amber were widely used. Many of these are polymers - from the Greek word poly, meaning 'many', and mer, meaning 'part'. Polymers are composed of giant molecules, made up of large numbers of a small molecule strung together in long chains. This small molecule is called a monomer (mono means 'one'). The search for synthetic materials started over a hundred years ago to replace materials like ivory, which were becoming scarce, and to make materi­als that could be moulded or extruded as fibres. The first plastics were semi-synthetic polymers and relied on modifying cellulose, the natural polymer in cotton. Later, completely synthetic plastics, such as Bakclite, were made.

Synthetic materials resembling ivory were widespread by 1900. They were used for all kinds of products, from knife handles, collars, and culls, to evening handbags. These plastics could be moulded when hot inlo shapes which became rigid on cooling. Ivoride, like other plastics, could be easily moulded to resemble intricately carved ivory. The early synthetic plastics were modelled to resemble the natural polymers.

Alexander Parkes (1813-1890) introduced a mouldable material made from cellulose nitrate. He dissolved cotton fibres in nitric acid, added a plasticizer such as camphor, and evaporated off the solvent. The material called Parkesine was used to make all kinds of domestic goods like hair slides. Parkes exhibited his first successful plastic in London in 1862.

By 1870 John Wesley Hyatt (1837-1920) was manufacturing cellu­loid, an ivory substitute, from cellulose nitrate. It was widely used for billiard balls and all kinds of decorative products, such as evening bags made in 1900.

When sulphur-containing compounds are heated with rubber, the rubber absorbs them, forming crosslinks between the chains of mole­cules. Large amounts of sulphur lead to hard, chemically resistant ma­terials, such as the vulcanite used to make fountain pens.

Bakelite, or phenolic resin (a synthetic plastic developed by Teo Baekeland), was used for domestic items such as clocks and electrical fittings. It is resistant to heat and has good insulating properties. The phenolic resins are always dark in colour. They are easy to mould and are strengthened using fillers such as textiles.

Film made of cellulose nitrate was introduced for motion pictures in 1887 and for still pictures in the following year. Cellulose nitrate is notoriously inflammable, so modern film is made from the safer plas­tic, cellulose triacetate.

In the 1920s the search for a light-coloured plastic with similar prop­erties to Bakelite, which was always black or reddish-brown, led to the ureaformaldehyde plastics. Using cellulose filters and suitable colour­ing materials, both white and coloured articles could be manufactured.

Some plastics can be extruded to form fibres. Textiles used to be derived from natural fibres. Regenerated cellulose from a viscose so­lution was introduced in 1892. This plastic material could be pumped through fine holes into acid to produce an artificial thread for tex­tiles. Large-scale production was possible with the introduction of a spinning box in 1900. The box collected the filaments without tan­gling them.

By the 1950s many different plastics had been developed. They were used in industry and throughout the house, especially the kitchen. Strong polyvinyl chloride (PVC) is used as a floor covering. Melanine formal­dehyde plastics, which have a good resistance to heat, water, and de­tergents, were introduced in the mid 1930-s. They are laminated by sand­wiching alternate layers of plastic and paper or cloth and pressing them to make formica for work surfaces. Other plastics, such as polystyrene, are used for buckets, blows, and jars. Unfortunately most plastics are not biodegradable; they do not rot away, and they may emit poisonous fumes when burned.

New plastics are being introduced all the time. The first of the ther­moplastic materials was polyvinyl chloride (PVC). Observed in the 1870s, it was not successfully produced until the 1930s. Waterproof and weather resistant, it has a wide ran.ge of uses: rigid when thick, it makes up guttering, toys, and curtain rails; flexible when thin, it covers electric cables, makes baby pants, and upholstery. Polyacrylic plastics include perspexs, a plastic of exceptioixally high transparency. Its re­sistance to shattering makes it invaluable for aircraft canopies. Poly­thene, or polyethylene, was first discovered in 1933. Like many plas­tics, it was some time before successful! commercial production was achieved in the late 1930s, when its valuable insulating properties were immediately pressed into service for wartime radar equipment. Rigid polyethylene was not produced until trie introduction of a catalyst in the 1950s. In the USA the Du Pont company successfully launched nylon-66, which revolutionized the textiles industry. It was strong, stretchy, and non-absorbent. Today it is difficult to imagine a world without plastics. Many new processes and products depend upon them. Wallace H. Carrothers (1896-19373 joined Du Pont in 1928. He used two chemicals in solutions (an acid and a diamine) to prepare nylon-66. Where the two solutions met, the liquid could be pushed out (extruded) into threads that were stronger than natural fibres. The dis­covery gave a huge boost to the textile industry and led to a revolution in fabrics.

Two alternating monomers are used to make nylon-66: adipic acid and hexamethylenediamine. Each has reactive groups of atoms at both ends of a straight molecule - acid groups in the former, and aniline in the latter. Each acid group combines with an amine to form long chains of alternating monomers. The diamine is dissolved in water forming the lower layer in the beaker, while the upper layer is a solution of the acid in hexane. Nylon is formed where the two reactances meet and can be pulled out of the beaker and wound around the rod.

Polyethylene is a polymer of ethylene monomers. Discovered in 1933, it did not become commercially available until 1939 after the problems of attaining high temperatures and pressures on a large scale were solved. Pressure vessel was used to prepare the first polyethylene samples. While examining the effects of very high pressures on ethylene gas, solid, white particles were observed. Fortuitously, a hole in the equipment had al­lowed oxygen from air to enter the chamber, which initiated (started) the reaction. This low-density polyethylene is soft, flexible, and clear. In the 1950s a catalyst was introduced, and rigid, high-density polyethylene was obtained.

All plastics fall into one of two categories depending on how they act when heated. Thermoplastic materials (polyethylene) soften each time they are heated. Thermosetting plastics will not soften again once they have been heated and cooled down (Bakelite). On first heating, these molecules form cross linkages which lead to a permanent rigid structure. They make components such as electric plugs.

Plastics increasingly find applications in replacement surgery because they do not react with their surroundings. Unlike transplant material from human donors, they do not prompt the body to reject them as foreign material.

Plastic tubing is being made from pellets of polyethylene. Waste pol­yethylene has been softened with hot water and ground up to produce the pellets. The plastic tubing is blown out using hot air, which shapes and dries the tubing. Recycled plastic is used in the construction indus­try, where impurities in it are not so important. Only thermoplastics can be recycled in this way.

Ответьте на вопросы по тексту:

1.When was the first synthetic plastic made?

2.What are polymers composed of?

3.Who introduced a mouldable material made fromcellulose nitrate?

4.Where and when did Parkes exhibit his first successful plastic?

5.Why was large-scale production of plastics possible in 1900?

6.Where are many different plastics used?

7.Why do plastics find applications in replacement surgery?

 

Текст 3

Synthesizing Diamond

Laboratories in India have recently reported that they have devel­oped a new technique to make gem quality diamonds. It is said that the diamonds so made are less expensive than those that are mined. This comes at an odd time when the market for diamonds was already de­pressed and is now accentuated by the economic slump in the far East. Gems worth Rs. 48, 000 crores are reportedly piled up in vaults all over the world waiting for customers.

Ever since Tennant proved that diamond was another form of car­bon 200 years ago, efforts have been made by scientists to synthesizes diamond. Many experiments claimed that sugar, oil and a host of other carbon containing materials had been subjected to secret processes that turned them into sparkling diamonds. While being very secretive about the details of their work, all of them appear to have used high tempera­tures and high pressures, often with the addition of metal powders and other chemicals in the attempts.

The most stable form of carbon at room temperature and pressure is graphite. It has, however, been known for a long time that the very high temperatures and pressures that existed deep under ground for millions of years arranged the carbon atoms into a cubic lattice arrangement to produce a crystal that was colourless, clear, lustrous and hard. The very hardness and resistance to chemicals gave this carbon crystal its name -adamant or diamant or later, diamond.

The phase diagram, or the graph that depicts how that state of carbon depends on the pressures and temperature, indicates that more than 200, 000 atmospheres (kg/sq.cm) and temperatures in excess of 3000 degrees Celsius must be applied to create diamonds. Early experimenters tried unsuccessfully to produce these conditions by different tricks. Hannay, for ex­ample, sealed oil and lithium metal into iron tubes and heated them; but his claim that he had produced small diamonds proved to be false.

Bridgman was the first scientist to realise that there could be no com­promise with the extremely high pressures and temperatures required to synthesise diamond. In 1910, he designed a screw type press with which he attained a pressure of 400 kilobars. Only tungsten carbide anvils were hard enough to take this pressure and so the 'melt' had to be contained between cylinders of this material. Needless to say, the active volume had to be very small. In his experiments, he could only get a pressure of 35 kilobars at the temperature of 2000 degrees Celsius.

The company General Electric redesigned the press that was capable of reaching 200 kilobars at a temperature of 5000 degrees Celsius for a period of many hours. They were also able to increase the active volume considerably and so were able to produce small, synthetic diamond stones, or grit on a commercial scale. Further improvements in design were made by Hall using a tetrahedral press, where the pressure was applied from four directions. This equipment was successful in making significant quantities of synthetic diamonds in five minutes with a pressure of ten kilobars at 2000 degrees Celsius. Metal powder or boron carbide added as a catalyst increased the production greatly.

In 1970, General Electric improved their technique greatly by intro­ducing seed crystals in the carbon material and could obtain large dia­monds of gem quality. It is reported that it took about one week to grow a five mm size diamond weighing one carat. The addition of metals, however, gave a certain tinge to the stone. It is known, for example, that impurity of 100 parts per million of nitrogen turns the diamond to a pale yellow type Ib crystal.

The General Electric synthetic diamonds varied in shade from F to in the diamond scale of colour and the clarity was sometimes good, up to the VS grade. With the addition of boron carbide in the melt, polycrys-talline diamond, also called carbonado, is grown. This is harder than single crystal diamond but lacks its clarity. It is, however, useful as a diamond cutting tool in scaifes and saws.

The process has been improved very much over the last decade and it is estimated that worldwide, about 40 tonnes of synthetic diamond grit are produced and marketed annually. The manufactures are located in the USA, Russia, South Africa, Ireland, Sweden and Japan. Exotic meth­ods have been used to generate the extremely high pressures and temper­atures that encourage the growth of diamond from carbon. One such method utilises shock wave.

The transient nature of the shock wave permits the use of materials softer that tungsten carbide to contain the carbon melt. Hard-nosed bul­lets or shells were fired into the active volume which was initially heated to a fairly high temperature. The impact of the bullet not only increased the pressure but the compression also heated the sample to the required temperature and beyond. In at least two experiments, the terrific blast wave from underground nuclear explosions was directed on to the car­bonaceous material. The success of these experiments are not generally reported as it is an extremely expensive technique and in any case, nucle­ar explosions are not continued.

Strangely enough, a very simple process can grow diamond crystals. This is by the decomposition of chemical vapour or CVD as it is called. The CVD process starts with a carbon containing gas such as methane which is decomposed by burning, electric discharge or laser heating. A carbonaceous gas, methane or acetylene is mixed with hydrogen and directed towards a hot filament which decomposes the gas and deposits small diamond crystals on a nearby heated surface.

The discharge is often replaced by a laser beam. The cheapest way is to direct an oxyacetylene flame on to surface. If the gas flow and mixture is carefully optimised, diamond crystallites nucleate and grow. The ad­dition of hydrogen seems to passivat e the surface and discourages the growth of graphite. So far only micron size crystals have been grown but efforts are under way to obtain bigger crystals and the recent report from Indian laboratories signifies success in this direction.

The unique properties that make a diamond so rare and expensive are: (a) its high refractive index of 2.42 and dispersion of 0.04 that gives in the lustre, (b) its lack of colour which is due to its purity, (c) its high thermal conductivity, even greater than copper, which makes it cool to touch and gives it the name of " ice", and (d) its being the hardest known material with ten on the Mohs scale of hardness.

There have been many attempts to make a material which is harder than diamond because scaifes can then be used more efficiently than the present method of using diamond to cut diamond. Cubic boron nitride was the first material to be made in the laboratory in the 1960s. Realising that reducing the distance between the atoms in a crystal and finding a crystal arrangement that would make this possible would increase the hard­ness of a material, the Laboratory for Physical Chemistry of Materials in France tried different mixtures of atoms and hit on ruthenium oxide. Crys­talline ruthenium oxide is now the hardest known material but has not been able to displace diamond from its position as the hardness leader.

It will not be very long before scientists discover a synthetic material which has all the properties of diamond such as its hardness, clarity and lustre and thermal conductivity. The demand for this wonder material is potentially so large that the commercial viability of the process to make it will be easily established.

 

Ответьте на вопросы по тексту:

1. What is graphite?

2. How did modern chemists manage to synthesize diamonds?

3. What factors could turn graphite into diamond?

4. What kind of equipment was produced for that purpose?

5. Who produced the equipment?

6. What is the hardest known material now?

7. Why can not it displace diamond?

 

Тексты для самостоятельного чтения. Семестр 4.

Строительство»

Вариант 1

Текст 1

British Architecture

Apart from some ancient churches, the oldest buildings you will see in Britain are castles. They are dotted all over the country, with many beautiful examples in Scotland and Wales. They were first built by the Normans after their invasion of England in 1066. The Tower of London dates from about 1078. Because of the Normans’ desire to control the population, they started to build castles everywhere, but especially in the more restless regions. For example, King Edward I built a series of massive castles in Wales at the end of the 13^th century; his aim was to keep Welsh under English rule.

As the dominance of the English crown was established, the need for castles diminished. So by the 15^th century the castle-building was over. Many Scottish castles are from a later period, but these are not military buildings; they are aristocratic family houses that imitated older styles.

Since the Middle Ages, architecture in Britain (as in most of Europe) has been based on three major styles: Gothic, classical, and modern. The great early cathedrals and churches are in Gothic style – tall, with pointed arches and highly decorated; they are covered in sculptures of people, animals and plants. The buildings are fantastic engineering achievements, constructed with very little machinery and designed by architects whose names have been forgotten. The tallest spire in Britain, at Salisbury Cathedral, is 123 metres high and was built in the 1330s. It is incredible that such size and perfection were achieved without a single crane or computer!

After the Gothic period, architectural fashion looked back to the classical age of Greece and Rome for its inspiration. So we see columns and triangular pediments as on Greek temples; round arches, domes and perfect Latin lettering as on Roman public buildings. Many of the finest London churches are in this style; St Paul’s Cathedral (built by Sir Christopher Wren between 1675 and 1710) is the biggest and most celebrated, but there are many more all over the city.

Not only churches were in the classical style. Rich aristocrats built huge and impressive houses surrounded by parkland; they are not such a grand scale that it is difficult to imagine that they were once private homes, but of course they had dozens and sometimes hundreds of servants.

Many of the most beautiful parts of British cities consist of houses in this style. The period of kings George I to George IV is known as Georgian period, and cities such as London, Edinburgh, Bristol and Bath still today have large numbers of elegant Georgian houses, which give the streets a striking sense of unity and design.

In the 19^th century, during the Victorian age (taking its name from Queen Victoria), architects went back to medieval Gothic ideas for their inspiration. At first sight it is sometimes difficult to tell whether a Victorian church is 100 or 500 years old! At the same time, classical styles did not disappear altogether. In fact, there was a “Battle of the Styles” between classical and Gothic. The British Museum (1823) was a victory for classical, and the House of Parliament (1836) for the Gothic. There was also debate about the use of iron and steel: should these new materials be visible, as in the new bridges and railway stations, or hidden, as in the Natural History Museum, London, where the metal frame is covered by coloured brick and stonework?

From the 1920s on, new ideas were transforming art and music, and architecture, too, was caught up in the modernizing culture. People wanted buildings which were not just copies of the past. Having abandoned both classical and Gothic styles, the challenge was to create – to invent – something really new. Luckily, this change in attitude came at the same time as exciting new engineering materials were becoming available. With concrete and steel together, and new types of glass, it was possible to escape from the traditional forms. For the first time in history, architects were free to make almost any shape they liked.

What makes the look of British towns and cities distinctive? The most striking feature is lack of blocks of flats. People prefer to live in individual houses – units with their own front doors and sometimes gardens. Perhaps this says something about the national character; a love of privacy and a lack of interest in the wider community. There is a proverb: “An Englishman’s home is his castle.” Whatever the deeper reasons for it, the result is that British towns and cities are full of two or three-storey houses. Only in the1950s and 60s did councils start building tall blocks of flats in the American style; but these have been very unpopular, and the cheaper ones are now being demolished.

Another distinctive feature of British buildings is the use of brick. Some of the oldest monuments, like Hampton Court Palace or Queens’ College, Cambridge, are made of brick. It remains the favourite material for new houses today. While the rest of the world prefers concrete, for some reason the British taste is for brick, at least in smaller buildings.

 

Ответьте на вопросы по тексту:

1. What are the oldest buildings in Britain?

2. What major styles is British architecture based on?

3. What are the main features of Gothic style?

4. What are the main features of classical style?

5. What are distinctive features of British town and cities?

6. Why do British people prefer to live in individual houses?

7. What is Hampton Court Palace made of?

Текст 2

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