Sources of power

Exercise 30. Read, translate and retell the text.

ADDITIONAL EXERCISES

Exercise 29. Retell the text in writing.

Exercise 28. Write if these statements are true or false.

Exercise 27. Answer the questions.

Exercise 26. Complete the sentences.

LISTENING COMPREHENSION EXERCISES

Exercise 25. Listen to the text “Engine and ladder companies”.

1. The first concern of firefighters is ….

a) to keep the fire from spreading; b) to put the fire out; c) to stretch hose lines.

2. After an alarm is received the engine and ladder companies ….

a) speed to the fire; b) make a plan of action; c) try to get information about the fire.

3. If the building isn’t ventilated, the heat and pressure of the gases can cause ….

a) fire spread; b) damage to property; c) an explosion.

4. Firefighters spread … covers over furniture and property.

a) woolen; b) rubber; c) silk.

5. The ladders on most trucks extend up to only about … storeyes.

a) eight; b) six; c) seven.

1. What are the two basic firefighting units in most fire departments?

2. Does ladder truck have other rescue equipment?

3. What do engine companies operate?

4. Who appraises the situation and directs the firefighters into action?

5. What are ladders used for?

1. All types of fires require the same plan of action to put it out.

2. Firefighters arrive to the scene of fire within an hour.

3. Ladder companies operate trucks called pumpers.

4. Firefighters open or break windows and sometimes cut holes in the roof or walls to ventilate the building.

5. Hidden sparks can cause another blaze.

The industrial progress of mankind is based on power: power for industrial plants, machines, heating and lighting systems, transport. At present most of the power required is obtained mainly from two sources. One is from burning of fossil fuels, i.e. coal, natural gas and oil, for producing heat that will operate internal- and external-combustion engines. Many of these engines will actuate generators, which produce electricity. The second way of producing electricity is by means of generators that get their power from steam of water turbines. Electricity so produced then flows through transmission lines to houses, industrial plants, enterprises, etc.

It should be noted that the generation of electricity by these conventional processes is highly uneconomic. Actually, only about 40 per cent of heat in the fuel is converted into electricity. Besides, the world resources of fossil fuels are not everlasting. On the other hand, the power produced by hydroelectric plants, even if increased several times, will be able to provide only a small fraction of the power required in the near future.

Much effort and thought is being given to other means of generating electricity. Sustainable approaches to energy supply are based on nonnuclear, renewable energy sources and more effective use of energy, through either improved technology or reduced energy consumption.

One is the energy of hot water. Not long ago we began utilizing hot underground water for heating and hot water supply, and in some cases, for generation of electric power. Another promising field for the production of electricity is the use of ocean tides and waterfalls. The energy of the Sun, which is being used in various ways, represents a practically unlimited source.

Using atomic fuel for production of electricity is highly promising. It is a well-known fact, that one pound of uranium contains as much energy as million pounds of coal. But the risks associated with nuclear energy are also great, as illustrated by the Chornobyl accident.

Дата добавления: 2014-12-29