Copy them in your exercise-books.

6. Read and translate the text.

Aluminium. One of the oldest and best known metal is aluminium.

It has some characteristics. First of all, it is a white silvery metal. Thanks to low weight and resistance to corrosion aluminium is very suitable for the bodies of vehicles and also for castings-gear-boxes, pistons, cylinder heads. Also it is one of the metals widely used in the industry. It is used for making cooking utensils, ladders, refrigerators, wrapping material. Aluminium foil is used for the heat insulation of houses. One of aluminum's characteristics is that it does not rust in the air. It is used in painting. Aluminium paint protects ironwork from rust, obliterates dark paint and reflects light. Any engineer must remember that aluminium is soft. That is why it is only used with other metals to make alloys light but very strong. Some important aluminum alloys are magnolium and duralumin (95% aluminium + 4% copper + 1/2% manganese 4- 1/2% magnesium). It can be tempered by heal treatment. This alloy is used to make aircraft, houses, furniture and motor pistons.

Copper. This metal is found in nature in the form of ores but sometimes it. is found in pure state. So we know pure copper. Pure copper has some specific, characteristics. They differ it from other metals. First of all it is reddish colour. Also it has corrosion resistant qualities. Copper is the best conductor of electricity. It is surpassed only by silver for conductivity of electricity. Thanks to copper's conductivity it is widely used for electrical wiring and cables, such as telephone and telegraph cables, making of electrical apparatus, parts of dynamos and electric motors. Copper with other metals is used in alloys. There are three important copper alloys.

The first is brass. Brass, including 20% zinc and 80% copper. It is important to know about zinc. Its colour is yellow when hot and white when cold. Zinc is a hard grey metal which acquires a protective coating of zinc oxide on its surface. It burns in oxygen and in chlorine with a bluish flame. Zink oxide is used in paints because it is non-poisonous and is not discolored by hydrogen sylphlike. It has a soothing effect upon the skin and is used in ointments and lotions. It is added to rubber for making racing motor treys. Zink is used in the making of dry batteries and in the process of galvanizing. In this way, iron is dipped into molten zinc, which forms a protective layer on its surface, and so prevents rusting. Galvanized iron is used in sheets for roofing and also for buckets and dustbins. This alloy of zinc and copper is header and cheaper than copper itself. It can be pressed into a shape. It resists corrosion. So brass hinges are used in preference to steel if they are exposed to weather.

The second is bronze. Bronze is an alloy of copper and tin. Tin is a silvery metal which is not corroded by air. Tin plate is suitable for cans in which acid fruit and other food-stuffs are packed because tin is not attacked by weak acids. For good containers, iron is coated with tin instead of zinc because tin is not subject to attack by acids in food. Bronze, including 20% tin and 80%copper is very tough. Bronze is used for making ship propellers, parts of machinery subject to hard wear and for doors and windows.

-And the third one is copra-nickel (75% copper + 25%nickel). Last one is used for the present "silver" coins.

For a very long time such a combination as supplies including metals lead, zinc with supplier is known. It was mentioned about zinc. It is high time to tell some words about lead. Lead is a grey malleable metal which melts at 327°C, which is low for a metal. Earlier it was used for roofing and for water piping because of its softness and resistance to corrosion. Today copper and iron have taken its place. Now lead is a very expensive metal. But lead is still used for roofing and for making waste pipes and sink traps because it is easily bent into shape, storage battery (accumulator) plates, cable sheaths, storage tanks for sulphuric acid, lead shot, solder, screens to stop harmful radiation from radioactive substances. Other lead alloy is a type of metal such as lead, tin, bismuth, cadmium. Lead monoxide is used for making glass that it is brilliant and sparking.

7. Reading for specific, information. Read the seventh and the eight paragraphs from the text and answer the questions to the text:

· For what lead is used?

· For what zinc is used?

· What colour is zinc?

· Why is the lead a very expensive metal?

· What metal can you see mostly in our life?

· What copper alloys do you know?

· What are specific characteristics of copper? What is the oldest and best known metal? What are aluminium's characteristics? What aluminium alloys do you know?

8. Read the text again and complete the spidergram:

9. Read the text again and complete the following sentences;

· Aluminum is the ... and best ... metal.

· Coppies found in nature in the form of... but it is sometimes

· found in ...

· ... is the best conductor of electricity.

· ... is a silvery metal.

· Tin is not attacked by ...

· ... is soft...

· ... is used for making cooking utensils, refrigerations.

· Aluminum protects .. from rust, reflects light.

· ... is used for making aircraft, houses, furniture and motor pistons.

· Tin plate is suitable for ...

· And the third one...

· ...have taken its place.

· It is added...

10. Read the fallowing statements and say whether they are true of false. Correct the false statements:

· Tin is a golden metal.

· Aluminum is the latest light metal.

· Tin plate is suitable for can.

· Bronze is very tough.

· Pure copper is of white colour.

· Tin is not corroded by air.

· Copper is founded in nature.

· Cupro-nickel is consist of 75% copper and 25% nickel.

· Tin is not subject to attack by acids in food.

· Copper is the worst conductor of electricity.

11. Match the parts of the following sentences:

•Aluminum        • is a silvery metal which is not corroded by air

•Copper             • is used for making ship propellers,

                          parts of machinery subject to hard wear and for doors and windows

•Tin                    • is found in nature in the form of ores but

                            it is sometimes found in pure state

•Zink                  • are also metals which occur in combination

                            with sapphire as sapheads

• Lead and Zink • is the oldest and best known light metal

• Bronze            • Is a moderately hard grey metal which

                             acquires a protective coating uf zinc oxide on its surface

Lesson 48

TOOLS FROM METAL

Warming - up

1. Discuss the following:

• Do you know any product of metal?

2. Match the following words with their Russian equivalents:

 

tools	• сооружать
saw	• храм
axe	• дерево
chisel	• гравий
tree	• мрамор
dwelling	• инструменты
erect	• прочный материал
temple	• раствор
manufacturing bricks	• штукатурка
durable material	• дома
wooden forms	• песок
solution	• стамеска
fastening	• топор
plaster	• вулканическая зола
oxid calcium	• пила
sand	• прикреплять
volcanic ashes	• деревянная форма
gravel	•промышленные кирпичи

• stone                                   • оксид кальция

• marble                                 • камень

3. Read the text and find new words from the text.

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