Circle the correct option to complete the definition. Plastic is a man-made material consisting of very large / small molecules. Plastic is heavy / light , has a high / low corrosion resistance, high / low strength-to-weight ratio and a high / low melting point. Match the types of plastic production with the correct pictures and definitions. Use a dictionary to help you. A B C 1 hollowed-out shape that is filled with liquid plastic, then set: 2 soft plastic pushed or drawn through a die of a cross-section profile: 3 plastic melted and drawn / spun into fibres: Can you think of three products for each type of plastic production? Complete the ‘metal facts’ with the words in the boxes. The students and teachers of a school have been asked to decide what type of chairs are going to be bought for the new building. Listen to the debate. Who supports which material? Listen again and write down two positive and two negative aspects mentioned about each material. What’s your opinion on the different kinds of material? Talk together. 31 drawing extruding moulding 32 a b copper aluminium tungsten alloy iron (2 ×) 33 Metal facts Metals are chemical elements that are used in a number of ways. They are usually solid, good conductors of electricity and heat, and shiny when clean. Metals are strong but also malleable, which means they can be bent and shaped. The most common metal found on Earth is (1) , mostly because it makes up such a large part of the Earth’s core. The chemical symbol is Fe. Steel, used in buildings, tools and cars, is a well-known (2) and made from (3) and a small amount of carbon. (4) (Al) is the most common metal found in the Earth’s crust. It is a good conductor of heat and is often used to make cooking pots. (5) (Cu) is a good conductor of electricity and is often used for making wires. It’s relatively soft. (6) , also known as wolfram, is a chemical element with the chemical symbol W. It has a very high melting point. 34 a b d52xj2 26 c 78 Language skills Extras Explore 6 The story of stuff Nur zu Prüfzwecken – Eigentum des Verlags öbv
RkJQdWJsaXNoZXIy ODE3MDE=