Lesson 2

Read and translate the text.

ENERGY

In the language of science energy is the ability to do work. There are various forms of energy, such as heat, me­chanical, electrical, chemical, atomic and so on. One might also mention the two kinds of mechanical energy—poten­tial and kinetic, potential energy being the energy of position while kinetic energy is the energy of motion.

It is well known that one form of energy can be changed into another. A waterfall may serve as an example. Water falling from its raised position, energy changes from po­tential to kinetic energy. The energy of falling water is generally used to turn the turbines of hydroelectric stations. The turbines in their turn drive the electric generators, the latter producing electric energy. Thus, the mechanical energy of falling water is turned into electric energy. The electric energy, in its turn, may be transformed into any other necessary form.

When an object loses its potential energy, that energy is turned into kinetic energy. Thus, in the above-mentioned example when water is falling from its raised position, it certainly loses its potential energy, that energy is changed into kinetic energy.

We have already seen that energy of some kind must be employed to generate the electric current. Generally speak­ing, the sources of energy usually employed to produce current are either chemical, as in the battery, or mechani­cal, as in the electromagnetic generator. Chemical sources of current having a limited application, the great quanti­ties of electric energy generated today come from various forms of mechanical energy.

The rising standards of modern civilization and grow­ing industrial application of the electric current result in an increasing need of energy. Every year we need more and more energy. We need it to do a lot of useful things that are done by electricity. However, the energy sources of the world are decreasing while the energy needs of the world are increasing. These needs will continue to grow as more motors and melted metals are used in industry and more electric current is employed in everyday life. As a result, it is necessary to find new sources of energy.

The sun is an unlimited source of energy. However, at present, only a little part of solar energy is being used directly. How can we employ solar energy directly to produce useful energy? This is a question which has interested scientists and inventors for a long time. Lavoisier and other great scientists of the past melted metals with the help of solar furnaces. Today, solar furnaces illustrate just one of the numerous ways to harness the sun. Using semiconduc­tors, scientists, for example, have transformed solar energy into electric energy.

Exercises

I. Learn the following words, groups of words. Translate the sentences.

1. battery — батарея. Volta made the first battery.

2. to change — изменять, преобразовывать. Electrical energy can be changed into mechanical energy.

3. chemical — химический. Chemical energy can be transformed into work or into electrical energy.

4. to drive — приводить в движение. Electrical current drives various machines at factories and mills.

5. to employ — использовать, применять. Electrical cranes are employed in industry.

6. generally — обычно. The pyrometer is generally used to measure high temperatures.

7. to harness — использовать энергию (воды, ветра, солнца). The scientists try to harness the wind.

8. generator — генератор. Generators generate electri­cal energy.

9. in one's turn — в свою очередь. The motor transforms electrical energy into mechanical energy; mechanical energy in its turn drives the machines.

10. kind — вид, род. There are all kinds of machines in our laboratory.

11. to produce — производить, создавать, выпускать. Where are these vacuum cleaners produced?

12. source — источник. There are different sources of energy

13. solar — солнечный. Solar energy can find various applications.

14. semiconductor — полупроводник. Semiconductors are widely used in industry.

15. to turn — превращать. The motor turns electrical energy into mechanical energy.

16. waterfall — водопад. The energy of a waterfall can be used to produce electricity.

II. Learn the following international words.

Moment, electricity, operation, laboratory, metal, theatre, industrial, motor, crane, ton, pyrometer, tempera­ture, mass, illustrate, industry.

III. Give short answers to the following questions.

1. Can one form of energy be changed into another form? 2. Does a generator produce mechanical energy? 3. Is the sun an unlimited source of energy? 4. Can we employ solar energy directly? 5. Have scientists transformed solar energy into electric energy? 6. Is potential energy the energy of motion? 7. Do we need more and more elec­tric energy every year? 8. Are there various forms of energy? 9. Do you use electric energy every day? 10. Can the energy of falling water be used to drive turbines? 11. Is kinetic energy the energy of position?

IV. Find the correct term out of the three given below.

1. The motor changes electrical energy into a) heat energy, b) chemical energy, c) mechanical energy.

2. The generator changes mechanical energy into a) chemical energy, b) electrical energy, c) light energy.

3. The battery changes chemical energy into a) solar energy, b) heat energy, c) electric energy.

4. The electric furnace changes electric energy into a) heat energy, b) chemical energy, c) mechanical energy.

5. The vacuum cleaner changes electrical energy into a) light energy, b) mechanical energy, c) solar energy.

V. For the words given in (a) find the Russian equivalents in (b).

a) 1. to transform; 2. device; 3. application; 4. chem­ical; 5. potential; 6. source; 7. station; 8. to produce; 9. to drive; 10. to serve; 11. to do without; 12. to make use of; 13. as for; 14. to play a part; 15. semiconductor.

b) 1. служить; 3. приспособление; 4. прибор; 5. использовать; 6. источник; 7. что касается; 8. потенциальный; 9. применение; 10. преобразовывать; 11. станция; 12. вырабатывать; 13. химический; 14. обходиться без чего-л.; 15. приводить в действие.

VI. Make up the annotation of the text and retell it.