Lesson 1. Energy

TEXT 1 A. Energy;

Grammar Exercises (The Tenses: Active and Passive Voice);

TEXT 1 B. Generators;

TEXT 1 C. Batteries.

Pre-Text Exercises

Active Vocabulary

I . Practise reading the words written below. You’ll come across them in text 1 a.

capacity ……………………….. material body …………………. coiled spring ………………….. electromagnetic ………………. to traverse ……………………... dimension ……………………... to expend ……………………… weight …………………………. pulley ………………………….. force …………………………... energy of position …………….. energy of motion ……………… waterfall ………………………. turbine ………………………… to generate ……………………. current ………………………… application ……………………. quantity ……………………….. to decrease ……………………. to melt ………………………… hydropower …………………… fossil fuel ……………………… furnace ………………………… semiconductor ………………… domestic ………………………. low-grade heat …………………

способность физическое тело пружина электромагнитный пересекать, вращать величина, измерение расходовать вес шкив, блок сила энергия покоя энергия движения водопад турбина вырабатывать ток применение количество уменьшать плавить гидроэлектрический топливное ископаемое печь полупроводник домашний тепло низкого качества

II. Put the words from the box into the correct columns below. Translate them into Russian.

electromagnetic, available, formally, radiation, chemical, domestic, semiconductor, environmentally, to decrease, dimension, economically, useful, motion, constant, gene-rator, generally, various, application

Noun (what/who?)	Adjective (what kind of?)	Verb (what to do?)	Adverb (in what manner?)
position … …	…	…	partly … …

III. Read text 1 a. Try to understand its content. Text 1 a. Energy

Energy is usually and most simply defined as the equivalent of or capacity for doing work. The word itself is derived from the Greek energeia: en, “in”; ergon, “work.” Energy can either be associated with a material body, as in coiled spring or a moving object, or it can be independent of matter, as light and other electromagnetic radiation traversing a vacuum. The energy in a system may be only partly available for use. The dimensions of energy are those of work, which, in classical mechanics, is defined formally as the product of mass (m) and the square of the ratio of length (l) to time (t): ml²/t. This means that the greater the mass or the distance through which it is moved or the less the time taken to move the mass, the greater will be the work done, or the greater the energy expended.

The idea of energy goes back to Galileo in the seventeenth century. He recognized that, when a weight is lifted with a pulley system, the force applied multiplied by the distance through which that force must be applied (a product called, by definition, the work) remains constant even though either factor may vary.

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, the above-mentioned example when water is falling from its raised position, it certainly loses its potential energy changing into kinetic energy.

We know 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.

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 at the same time as 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. The Sun radiates to our planet great amount of energy. This energy input fuels all our biological processes and is the original source for hydropower, wind power, and fossil fuel resources. Environmentally and economically, the Sun is our greatest energy source. Lavoisier and other greatest scientists of the past melted metals with the help of solar furnaces. Using semiconductors, scientists, for instance, transformed solar energy into electric energy. Why then is the direct use of solar energy so limited for industrial, domestic, commercial, and transportation purposes?

First, this kind of energy arrives in small quantities – only about one kW per square meter; second, it doesn’t arrive at all during night hours. Third, it is very difficult to transform it into useful energy forms except low-grade heat.

Any modern production is simply unthinkable without electrical energy. Many machines use it, they change energy from one form to another. Devices that are operated with electrical energy help us to work. Indeed, electricity plays an important part in modern life.