Externé štúdium letný semester 200 7

1. Externé štúdium letný semester 2007

2. Obsah konzultácie • Metals - steel • Robots • Energy – resources / graphs

3. METALS – STEEL METAL PROPERTIES • Copper Good conductor of heat and electricity. • Bends and stretches easily. • Cast Iron Hard. Strong. Stiff. • Lead Low melting point. Does not corrode. oft. Heavy. • Aluminium Very light. Strong. Resists corrosion. Good conductor of heat. • Steel Very strong. Easy to shape. Tough.

5. STEP 1Make a chart like this. Fill it in using the information from the experiment. Aim of the experiment: to test the effect of heating and quenching two pieces of steel Type of steel low carbon high carbon Blows to bend to 90° before heating: 9 17 after heating: 9 --- Effect noted: The low carbon steel was unchanged by the heating and quenching.The high carbon steel became very brittle.

6. low carbon steel black steel mild steel 0.1% carbon steel high carbon steel silver steel shiny steel 1 % carbon steel STEP 2There are several names given for each of the two pieces of steel. Write them down in two lists.

7. STEP 3Find words in the INPUT which mean the same as: • easily broken; it won't bend = brittle • to break = to fracture • to make something hot = to heat • to make something cooler = to quench • hit = blow • reflecting light = shiny • the same; standard = uniform • about = approximately

8. Why did the silver steel break, when the mild steel showed no change? • Because they contain different amounts of carbon, the particles in the two steels are affected differently by different temperatures.

9. STEP 5 Listening task • Metals are easy to distinguish from non-metals. • Magnesium burns easily. • All metals have the same properties. • All metals are shiny. • Most metals react with oxygen. • Silicon is a hard metal. • Sodium, calcium, potassium and magnesium are all metals. • There are more non-metals than metals. a F b T c F d T e T f F g T h F

10. We are all so familiar with metals that it might be quite a surprise to be asked the question: „What is a metal?“ Take magnesium for example. It burns easily. Why then, do we regard magnesium as a metal similar to, say, iron, which will not burn? The most important properties that distinguish metals from non-metals are: • They reflect light and thus are shiny. • They are good conductors of heat and electricity. • They combine with fluorine and chlorine. • Most react with acids and with oxygen. Apart from these similarities, metals show a great deal of variation. Gold, lead and sodium are very soft materials - much softer, for example, than silicon and graphite, both non-metals. Many metals corrode easily. Gold, chromium and platinum, however, do not. Some metals are very active: sodium, calcium and potassium combine easily with oxygen, chlorine and fluorine. Gold, silver and mercury, on the other hand, do not form compounds so easily. Metals far outnumber non-metals: only 20 of the 103 elements known today are non-metallic.

11. STEP 6 ReportingInstructions for tempering a steel chisel 1 Take a steel chisel. 2 Hold the chisel firmly in a pair of tongs. 3 Place the chisel in a furnace. 4 Heat it to 850 degrees Centigrade. 5 Take it out of the furnace. 6 Quench it in tepid water. 7 Clean the tool with emery cloth. 8 Gently re-heat it over a bunsen burner. 9 When the metal reaches the required temperature, quench it again.

12. Now turn these instructions into a report First we took a steel chisel. We held the chisel firmly in a pair of tongs. We placed the chisel in a furnace. We heated it to 850 degrees. We took it out of the furnace. We quenched it in tepid water. We cleaned the tool with emery cloth. We gently re­heated it over a bunsen burner. When the metal reached the required temperature, we quenched it again.

13. ROBOTSROBOTS -THE IDEAL WORKERS? We hear many complaints about work in factories: the work is often boring, heavy and repetitive; the operative does not have to think about the work; he gets no job satisfaction. The answer: a robot. For many jobs a robot is much better than a human operative. Once it has been programmed, it will do its job over and over again. It never gets bored; it works at a constant speed; it doesn't make mistakes; its work is always of the same standard; it doesn't get tired; it doesn't go on strike; it can work for 24 hours a day without breaks for food, rest or sleep; it doesn't take holidays or demand higher wages. Robots have other advantages, too. They can be designed to do almost any job. You can't change the human body, but a robot's arms, for example, can be made to move in any direction. Robots can also do very heavy work and they can operate in conditions that are too dangerous, too hot or too cold for people to work in. They can work under water, in poisonous gas and in radioactive areas. And on top of all this, robots never complain.

14. ADVANTAGES OF ROBOTS They never get bored. They work at a constant speed. They do not make mistakes. Their work is always of the same standard. They don't get tired. They don't go on strike. They can work all day without a break. They don't need holidays. They don't ask for higher wages. They can be designed to do almost any job. They can do very heavy work. They can work in conditions where humans can't. They never complain. DISADVANTAGES OF HUMANS They get bored Their work rate varies. They make mistakes. Their work is not always of the same standard. They get tired. They sometimes go on strike. They need breaks. They need holidays. They ask for higher wages. They can do only certain jobs. They can't do very heavy work. They can't work in all conditions. They sometimes complain. Make a list of these advantages, and the disadvantages of human beings that are implied.

15. Complete this paragraph with appropriate words from the INPUT. Robots are particularly useful for ................... in places where ................... would die. They don't .......... air so they can be used in space or ...................... . Special ................... have also been ..................... for handling ......................... materials. A number of industrial and military ......................... are also used to ................... in ......................... gases. So in many ways robots mean that people do not have to ................ in ......................... jobs. But, of course, ........................... are still needed to ......................... and repair the robots.

16. Find words or expressions in the INPUT which mean the same as: • worker = operative • unchanging = constant • enjoyment of your work = job satisfaction • repetitive = boring, because it never changes • to go on = to stop work for e.g. strikehigher wages

17. The advantages human beings have over robots It is obvious that robots have many advantages over human beings. However, it is also true that humans can do many things that robots can't. For example, humans can carry out a task without having to be told exactly how to do it first - in other words, they don't always have to be programmed. Humans can walk, run, swim, drive cars, fly aeroplanes, and so on, but robots are usually fixed in one place. If they are able to move, robots can do so only in a very limited way. Another advantage humans have is the way the same person can do jobs as different as making a cup of tea and designing a new type of motor car. And unlike robots, people can know whether what they are doing is good or bad, and whether it is boring or interesting. Also, robots are only just beginning to be able to understand speech and writing, but humans can communicate easily with each other by these methods, and by many others - telephone, drawings, radio, and so on - as well. And we should not forget that robots owe their existence to humans - we make them, repair them and control them, not the other way round. Finally, humans can produce new little humans by themselves!

18. Make notes of the main points. • humans can think for themselves • humans are much more mobile • a person can carry out a wider range of jobs than a robot • humans have feelings. • humans are able to communicate with each other much more efficiently - humans can respond to emergencies • humans are the creators of robots • humans can reproduce themselves

19. ENERGY – RESOURCESENERGY DIVISIONS • How does modern industry get the huge supplies of energy it needs? Here's how the energy cake has been divided up since 1925. As you can see, coal was the most widely-used fuel before the middle of this century. However, since the 1950s the use of coal has declined rapidly, and oil and natural gas have gradually replaced it as the main energy source. They now provide about three­quarters of the world industrial energy supplies. • The chart also shows that the use of hydro­electricity grew between 1925 and 1955, but since then it has stayed at a figure of 6%. Nuclear power provided only a fraction of the industrial energy supplies in 1970, but it now meets 10% of the need. • In the last 60 years the world's industrial energy demand has increased by 800%, and this trend is likely to continue. Since fuels such as oil and gas will run out during the next 50 years, we will have to find new ways of getting the energy we need. The energy pie of 2025 will probably include a large slice of solar power.

21. Language point • The energy cake: This is a common metaphor when referring to something that is divided (pie chart). • Natural gas: This is gas taken from the ground, compared with 'town gas' which is made of coal. • Pie chart: This kind of graph is used for showing shares or dimensions of a fixed amount. Thus it is particularly useful for showing percentages: total 'pie' = 100% • Only a fraction: only a very small part. • hydro-electricity: electricity from water power. • solar power: power from the sun.

22. Find words similar in meaning to these: • use instead of - replace • supply - provide • satisfy - meet/provide • general direction - trend • finish - run out • requirements - needs

23. Find words opposite in meaning to these: • little-used - widely-used • increased - declined • rapidly- gradually • large amount - fraction • stop - continue

24. Why do you think the proportions of fuels used have changed so much? • New technology for exploiting resources e.g. oil, water, gas. • New needs - motor car, aeroplanes. • Increased use of electricity. • Pollution from coal. • Coal is a very bulky material, so expensive to transport. • Countries want to exploit their own resources, rather than importing.

25. What types of graphs do you know? bar graph line graph pie chart

26. What advantage does a pie chart have over a bar or line graph? A pie graph shows proportions more clearly.

27. What do you notice about the order of the items in the graphs? • Items shown in two graphs should be in the same order in both. • It is conventional to start at 12 o'clock and move in a clockwise (or anti-clockwise)direction from the largest to the smallest. Obviously, in the second graph it is not so since the order remains fixed only the proportions have changed.

28. Complete these sentences with the appropriate letters from the pie chart. • E is the same asF about • B is roughly the same as C approximately • A is much greater / larger thanF • F is much smaller than A