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Unit 14 - Materials of the Modern World IntroductionOne of the essential requirements for any technological advancement is the availability of the right kind of materials for use. The importance of this is shown by the use of names such as Stone Age, Bronze Age and Iron Age for successive cultures in ancient times. More recently, in the nineteenth century, steel (an iron alloy) became the dominant material for making machinery, bridges, weapons, cars and many other items. In the twentieth century, the invention of plastics and composite materials have opened up a whole range of technological applications. This Unit is about these two families of new materials. The raw materials from which plastics are made are explored. Their wide applications due to their useful properties are studied. Problems related to the use and disposal of plastics are also discussed. Many modern technological applications require materials that are strong and stiff on the one hand and light and heat-resistant on the other. The development of composites to meet these requirements is at present a major concern of material scientists and offers exciting possibilities to man in the future. The latter part of the Unit presents students with a brief introduction to this important area of technological advancement. Unit ObjectivesAll students should 1.recognise crude oil as a mixture of hydrocarbons 2.be able to outline how useful materials are separated from crude oil by fractional distillation 3.be able to give examples of some major uses of the different fractions from crude oil 4.recognise molecule as group of atoms that forms the smallest stable unit of some elements or compounds 5.be able to give some common examples of molecules 6.recognise plastics as macromolecules built up from smaller molecules 7.be able to describe some of the properties of plastics 8.show concern for environmental problems associated with the disposal of plastics and a willingness to reduce the generation of plastic waste 9.be able to propose some possible solutions to the problem of plastic waste 10.be able to give some examples of composite materials 11.recognise that composite materials are made by combining two or more materials together to give strength and flexibility 12.appreciate that research in material science has helped improve our quality of life
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The more able students should 1.acquire some knowledge of degradable plastics 2.be able to relate some common plastics to their uses 3.acquire some knowledge about natural composites