Some Properties of Matter: Методические указания по английскому языку

М И Н И СТ Е РСТ В О О Б РА ЗО В А Н И Я РО ССИ Й СК О Й Ф Е Д Е РА Ц И И В О РО Н Е Ж СК И Й ГО СУ Д А РСТ В Е Н Н ЫЙ У Н И В Е РСИ Т Е Т К афедра ан глийскогоязыка

М Е Т О Д И ЧЕ СК И Е У К А ЗА Н И Я для ст уден т ов 1 курса дн евн огоот делен ия физич ескогофакуль т ет а

С оста вите л ь

В орон еж 2002

О .А . Гре кова

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Д а нны е м ет о ди ч ес ки е ука за ни я вклю ч а ю т т екс т ы по д о бщ и м на зва ни ем « Some properties of matter» с о про во ж да ю т с я упра ж нени ям и , на целенны м и на ра зви т и ена вы ко в ч т ени я и го во рени я на о бщ ена уч ны ет ем ы . Предна зна ч ены для с т удент о в 1-го курс а фи зи ч ес ко го фа культ ет а .

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Unit 1 I Pre-reading task:

1. Check up the meaning of the following words: Verbs: condense, prevail, boil, melt, exist, vary, emphasize, bind (bound, bound), liquefy, solidify. Nouns: solid, liquid, steam, spout, drop, pressure, vessel, clay, inch, treatment, crust. Adj: invisible, tiny, minute, rare, noble, aerated (drink), troublesome, pure, crystalline. Adv: naturally, relatively, rapidly, nearly, tightly, somewhat to and for. 2. Guess the meaning of the following words: Silicon, neon, argon, oxygen, zinc. II Reading: 1. Read the1st part of the text. Some properties of matter I Matter can exist in three forms, solid, liquid, and gas. However, these are not different classes of matter, but different states – that is, whether a particular substance, say the metal zinc or water or nitrogen, exists as a solid, a liquid, or a gas depends upon the temperature, and especially, in the case of gases, the pressure. Water is the simplest example. At the low temperature which prevails in many parts of the world, especially on the mountain-tops, water exists naturally in the solid form. When water boils it turns into an invisible gas, steam. You must not be misled by the cloud that forms near the spout of a boiling kettle, for this consists of tiny drops of hot water formed by the steam condensing in the relatively cold air. Consider the metal zinc, which we call a solid, for such it is at ordinary temperatures. It melts to a liquid at 419o C., and this liquid boils to an invisible gas at 907 oC. Now take the gas nitrogen, which is the main part of our atmosphere. At a very low temperature of – 196o C. and ordinary atmospheric pressure, it turns to a liquid, at a lower temperature, - 210 o C., it becomes a solid. All gases have now been liquefied and solidified, although some require a high pressure and low temperature to condense them. Liquid air, nitrogen, and oxygen are much used in some branches of industry and can be bought like any other liquid. Of course they require special vessels to prevent them boiling away rapidly at ordinary room temperature. Whether, then, a substance exists as solid, liquid, or gas is a question of pressure and temperature, not of constitution. Comprehension check: a) What are the states of the matter? Give the examples. b) Which substances are much used in different parts of industry? c) Complete the statement: constitution, gas, pressure, solid, temperature, liquid. Whether a substance exists as: .........., ........., or .......... is a question of .......... , and ........., not of ...... . 2. Read the 2 nd part of the text.

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Some Properties of Matter II All matter consists of very minute particles called atoms. In the world around us there are over 90 kinds of atoms which have different chemical properties and so can be separated and prepared by chemical means; these are called elements. All the countless thousands of different kinds of substances around us are made up of combinations of elements. The commonest element is oxygen, which in the free state is a gas that makes up, by weight, nearly a quarter of the earth’s atmosphere, but which exists in combinations in so many solids that it constitutes about half the weight of the earth’s crust. The next commonest element is silicon, which, combined with oxygen, makes up rocks and sands; and the next aluminium, which also exists in combination in common kinds of rocks and clay. Neither of these two elements exists in a free form in nature, and 150 years ago they were unknown. Atoms are very, very small. The atoms of different elements vary somewhat in size, but they are all about one hundred-millionth of an inch across, the smallest being about half this and the largest about twice this. Gases are the simplest form of matter and the best understood. Gases belonging to a certain group, the so-called rare or noble gases, are elements consisting of single separate atoms: we may mention as typical rare gases neon and argon, which are used in certain electric discharge lamps. these gases are also called monatomic (that is, one-atomic), to emphasize their nature. Most gases, however, consist of particles made up of two or more atoms. Such groups of two or more atoms closely bound together are called molecules. Most gases, however, are not elementary, that is, do not consist of one kind of atom only, but consist of molecules in which different sorts of atoms are combined. Thus in carbon dioxide, the gas used in aerated drinks, the molecule consists of one atom of carbon and two atoms of oxygen, tightly bound together. We may say that all gases are made up of molecules if in the case of the rare gases we consider a single atom as a particularly simple form of molecule. In the gases the molecules are separated by, on the average, distances large compared to their size. In liquids and solids conditions are quite different, the atoms and molecules being very close to one another, so that the space between them is small compared to their size. In the case of solids the molecules and their atoms keep to the same place: they are like a tree shaking in the wind, which, although it moves somewhat to and fro, stays in the same spot. In the case of liquids the molecules slowly move, like a shaking man shouldering his way through a crowd, not as they do in gases, with long free runs. It is the difficulties caused by the closeness of the molecules that make the behaviour of solids and liquids less simple than that of gases. Great many solids have a crystalline form: common examples are salt and sugar, less common examples are diamonds and rubies. In a crystal the atoms are all arranged in a regular pattern. Pure metals are simple solids, for they are elements, each consisting of one kind of atom only. Copper consists of copper atoms only, zinc of zinc atoms only. Many familiar metals are, however, melted together. Brass, for instance, consists of copper and zinc. A surprisingly large number of substances have a regular crystalline structure, even wool. There are, however, some substances, such as dough, which do not, and they are very troublesome to handle scientifically.

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In a way liquids are more troublesome to understand than solids, for they have no regular structure, since the molecules do not keep to their places. On the other hand they have the advantage that, at a fixed temperature, their properties are fixed. You do not know how a metal will behave unless you know the history of its treatment, but the properties of liquids at a given temperature and pressure are definite.

a) b) c) d) e) f) g) h) i)

Comprehension check True or False: In the world there are only a few kinds of atoms. At ordinary room temperature oxygen is a liquid. Silicon and aluminium were known more than 250 years ago. Gas is the simplest form of matter. Neon and argon are not elementary, they consist of molecules in which different sorts of atoms are combined. In gases the molecules are separated by, on average; distances large compared to their size. In the case of solids the molecules and their atoms keep to the same place. Great many solids have no crystalline form. Liquids have a regular structure.

III Writing: 1. Find out the names of the substances, used in the text and make up a list. At ordinary room temperature they are: Gases Liquids Solids 2. Write a short summery of the 2nd part of the text.

Unit 2 I Pre-reading task:

1. Check up the meaning of the following words: Verbs: weigh, measure, pump out, distinguish from, imagine, gain, depend on. Nouns: volume, balance, weight, sphere, pull of gravity, surface, pound, foot (feet), muscle, circumstances. Adj: obvious, sensitive, glass, sealed, fixed. Adv: clearly, perhaps, however, partly. 2. Match the lines: 1) 2) 3) 4) 5)

weight of a) is the amount of space that it contains or occupies smth. pull of gravity b) is how heavy it is, which you can measure in units such as: kilos or pounds mass of smth c) is the force which makes things fall when you drop them sphere d) is a round three-dimensional shape like a ball volume of e) is the amount of physical matter that it has. smth

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II Reading: What is mass? Matter is any real substance that can be weighed and measured. Clearly, then, stone or wood or paper or any other solid is matter. So is water or milk or any other liquid: we can weigh it and measure its volume, that is, the space it takes up, in a glass vessel suitable marked. It is, perhaps, not quite so obvious that air is also matter. However, it can be weighed, for on a sensitive balance a sealed glass vessel from which all the air has been pumped out weighs less than the same full of air. It is interesting to guess the weight of air in the room in which you are sitting. The weight depends upon the temperature. All other gases, such as hydrogen and carbon dioxide, are, of course, also forms of matter. Matter, then, may exist as solid, liquid, or gas. The quantity named mass is fundamental for the study of physics. A very important point is that mass mast be carefully distinguished from weight, which is the gravitational pull of the earth on the body. The mass of a piece of matter, say an iron ball, always remains the same; it’s a property of the body that doesn’t change under any conditions that can be imagined. The weight, however, can change. For instance, it is slightly less if the ball is 10 miles up in the air, or in a very deep mine. This change of weight could be measured with a very sensitive spring balance of some kind. Actually, very sensitive methods of measurement show that a body has slightly different weights at different parts of the earth’s surface, owing partly to the fact that the earth is not a perfect sphere. The effect is much too small to have practical importance. Perhaps a clearer notion will be gained by supposing our iron ball taken to the moon. Its mass will, of course, remain the same. But the pull of gravity at the surface of the moon is only about a sixth of what it is at the surface of the earth, owing to the fact that the moon is much smaller than the earth. Our spring balance, which gave the weight of the ball as 6 pounds at the surface of the earth, would show us the ball as weighing only about 1 pound. Supposing that a man could live healthily on the surface of the moon, his mass would remain unchanged, but his weight would be so much lessened that he could jump easily something like 30 feet high, if his muscles worked as usual. Mass, then, is a fixed property of any piece of matter, but the weight depends on circumstances. Comprehension check a) b) c) d) e)

What is matter? Is there any difference between mass and weight? Why does a body have different weights at different parts of the earth ’s surface? What is the pull of gravity at the surface of the moon? Which property of a body depends on circumstances?

III Writing: 1. Write a short summery of the text. Unit 3

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I Pre-reading task:

1. Check up the meaning of the following words: Verbs: multiply by, lift, possess, be at rest, cause, pull. Nouns: agent, unit, area, capacity, speed, spring, windmill, rate, engine, virtue. Guess the meaning of the words: cylinder, piston, horse-power, watt. Adj: precise, straight, constant. Adv: by virtue of smth. II Reading: Force, pressure, work, energy, power and what such words mean. There are various words, which are used without particular care in everyday life that have a precise meaning in physics and science in general. Such words are force, pressure, work, energy, and power, and we have to consider what they mean. Force is any agent which causes bodies which are at rest to move, or which causes bodies which are moving in a straight line at a constant speed to change their speed or direction, or both. The pressure on a surface is the force per unit area. Thus, suppose a cylinder and a piston of diameter 4 inches, which means an area of 12.57 square inches. If the pressure in the cylinder is 200 pounds weight per square inch, then the force on the piston will be 2514 pounds weight. A pound is a unit of mass, and the unit of force, in the British system, is the force with which gravity pulls the pound mass, and so is called the pound weight. A pressure must always be given per unit area – ‘per square inch,’ ‘per square foot,’ ‘per square centimetre,’for instance. Now, work. The work is measured by the force multiplied by the distance moved. One of the commonest forms of work is to lift a body against the pull of gravity, when the work done will be given by the weight multiplied by the vertical distance moved. This is used to define the British unit of work, which is the foot-pound, namely the work required to lift 1 pound 1 foot. Energy is the capacity for doing work. Energy which is possessed by virtue of position is called potential energy. Thus the energy of a coiled spring which is used to keep a watch going is potential energy. A body can also have energy through its motion. The wind is a very good example, because it’s widely used for turning windmills of one kind or another. Energy of motion is called kinetic energy. Power is the rate of doing work, and measures, among other things, the capacity of an engine. The British unit of power is a foot-pound per second, but the practical unit is the horsepower. The international unit of power is called the watt, after the same James Watt The notions we have discussed are necessary for an understanding of the fundamentals of physics. II Writing: 1. Write a short summery of the text. Think of the following: Force; Pressure; Work; Energy; Power.

Unit 4

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I Pre-reading task: 1. Check up the meaning of the words: Verbs: put forward, push, strike, attempt, bring into play, deal with, be proportional to, multiply by, depend upon, double, treble, neglect, drop, increase, govern, take into account. Nouns: consideration, rock, velocity, impulse, resistance, height [ ], calculations, gun, bullet, grain, dust. Adj: celebrated, heavy, smooth, level, rough [ ], visible. Adv: strictly, freely, namely, nearly, gradually. II Reading: 1. Read the text, find out the examples of F. C. Three laws of motion (I. Newton ) The great Sir Isaac Newton, who may be considered to be the founder of modern physical science, put forward three celebrated laws of motion, which are at the basis of all scientific considerations of movement. Newton’s first law of motion can be stated as follows: if a body is at rest it will remain at rest unless acted upon by an outside force, when it will at once move, and if it is moving in a straight line at a constant speed it will continue to do so unless acted upon by an outside force. This may at first sight seem to be contrary to what happens every day before our eyes. We can push against a heavy body, a rock resting on the earth, without moving it, and if we set a body in motion, for instance by striking a ball lying on a smooth and level piece of ground, it will not continue to move, but will come to rest. The fact is that when we move, or attempt to move, any body in contact with another body there is an outside force brought into play, the force of friction. The size of this frictional force depends upon the nature of surfaces, whether rough or smooth, and upon the force which presses the bodies together. In the case of a body resting on a surface, this force pressing the bodies together is the weight of the body. In the case of the heavy rock resting on the earth, the frictional force which has to be equalled if it is to move is so large that, for all practical purposes, the rock can be considered as a part of the earth. In the case of the rolling ball, the friction will be a small force, acting all the time that the ball is moving, which will gradually bring the ball to rest. The first law of motion is strictly true if we take all the forces, including that of friction, into account. Newton’s second law of motion deals with bodies changing their speed, and was expressed by him somewhat as follows: the change of motion of a body is proportional to the force acting on the body and takes place in the direction of the force. What Newton called ‘motion’is now called momentum and takes into account both mass and velocity: in fact it is mass multiplied by velocity. Thus if a force is acting steadily on a body in a given direction, the velocity in that direction will increase steadily. With a force of the same size acting on a smaller mass the velocity will increase more rapidly. The total change of velocity will depend upon how long the force acts. The force multiplied by this time of action is called the impulse. So the second law is expressed thus: the change of momentum of a body is equal to the impulse which produces it, is in the same direction. To get a clear notion of what this means, let us consider the case of falling bodies. First of all, we observe that the force of gravity pulling the body down is proportional to the mass of

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the body. For instance, doubling the mass means double the momentum and double the impulse, for a given time. So that the rate of fall at any moment after the start is the same whatever the mass: neglecting the air resistance, we see that a 2-pound weight and an 8-pound weight, dropped at the same moment from a height, will keep level and reach the ground together. Since the increase in velocity is proportional to the force, which is unchanging, the rate of increase of fall must be unchanging. The rate of increase of velocity is called acceleration, so that the man of science says that the acceleration during free fall under gravity is constant. Thus to be quite clear, a body falling freely from rest will have a velocity of 32.2 feet per second (ft/sec) at the end of 1 second; double that velocity, namely 64.4 ft/sec, at the end of 2 seconds; treble that velocity, namely 96.6 ft/sec, at the end of 3 seconds, and so on. Of course, as the velocity increases the distance travelled per second also increases. The acceleration of gravity (g) is the most important figure in science, and comes into all kinds of calculations. Newton’s third law of motion is that reaction is always equal and opposite to action. That is, if two bodies, A and B, act upon one another, the action of A on B is always equal in magnitude and opposite in direction to the action of B on A. Let us make this clear. When a gun is fired the bullet pushes the gun back with a force equal to that with which the gun pushes the bullet forward. Owing to its much greater mass it does not move nearly so fast as the bullet, but the speed can be exactly calculated. Another example is given by the rocket. The downward rush of gases at very high speed results in the body of the rocket being pushed upward. We have now considered Newton’s three laws of motion. They are of immense importance, governing as they do the movements of every machine and engine and of every object large enough to be visible, from a grain of dust to a planet. Comprehension check: True or False. 1) When we move a body there is a force of friction. 2) The size of the frictional force depends upon the time 3) The first law of motion isn’t true if we take all the forces into account. 4) The force multiplied by the time of action is called the impulse. 5) The rate of fall at any moment after the start depends upon the mass. 6) As the velocity increases the distance travelled per second also increases. 7) When a gun is fired the bullet pushes the gun back with a force different from that with which the gun pushes the bullet forward. III Grammar: Future Simple; First Conditional Future Simple: Will + inf. (without ‘to’); will not = won’t; (-), (?) No’ Do, Does’ Use: a) spontaneous decisions: I will give you your book back next week. b) predictions: It will rain tomorrow. First Conditional: If + Present Simple, Will + inf. (without ‘to’) Use: - possible condition and a probable result in the future: If it rains, I’ll stay at home. What will you do, if it rains? 1. Put the verb in brackets into the correct tense. If there is no verb, use ‘if’. a) If a body (be) at rest, it (remain) at rest unless acted upon by an outside force.

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b) … we (strike) a ball lying on a smooth and level piece of ground, it (not/continue) to move, but (come) to rest. c) … a force (act) steadily on a body, in a given direction, the velocity in that direction (increase) steadily. 2. Prepositions: out, from, on, by, into, to, to; d) ‘What time will you arrive?’‘I don’t know. It depends … .the traffic’. e) If one amount is proportional … another, it always remains the same fraction of the other. f) 2 multiplied … . 3 is equal … .2 plus 2 plus 2, which equals. g) If you take smth. … ..account you consider it when you are thinking about the situation h) They also have to carry … ..many administrative duties. i) The film was quite different … ..what I expected. IV Writing: 1. Write a short summery of the text. Unit 5 I Pre-reading task: 1. Check up the meaning of the following words; Guess the meaning of the underlined words; Find out the names of the substances. Verbs: expand, contract, attach to, be filled with smth., freeze, graduate, melt, be divided into, correspond to, fasten, heat, bend, compare to, diminish, convert into, suffice, contain, stir, imprison to, circulate, convey, absorb, behave. Nouns: thermometer, exception, dimension, (below/above) freezing-point, mercury, bulb, stem, bore, boiling-point, steam, thickness, scale (centigrade scale), division, expansion, strip, limit, absolute zero, furnace, interior, explosion, bomb, friction, generation, establishment, thermodynamics [ ], calorie, amount, steam-engine, surroundings, boiler, condenser, fraction, conduction, convection, pot, rod, copper, silver, lead, cell, conductor, balsa-wood, ray (infra-red rays), invar. Adj: odd (liquid), atmospheric, low, high, bimetallic, accurate, available, noticeable, poor, empty, responsible, thermal. Adv: Similarly, unlimitedly, extremely, continuously, relatively. II Reading: Heat I The notion of temperature is fundamental to the consideration of all heat problems. Temperature is a measure of the degree of hotness or coldness of a body. Temperature is measured by means of a thermometer depends upon the fact that most solids and liquids expand as their temperature rises. There are one or two exceptions. There is, for instance, a kind of steel called invar which doesn’t change its dimensions as temperature changes. Another exception is that very odd liquid water, which has many strange properties. As water gets colder it contracts, which is ordinary behaviour, until it reaches the temperature of 4C, above freezing-point. After that, as it gets colder, it expands.

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A common form of thermometer is the mercury thermometer, consisting of a glass bulb attached to a stem with a fine bore. The bulb and a short part of the stem are filled with mercury. When the thermometer becomes warmer the mercury expands. Of course the glass expands too, but not as much as the mercury, so the mercury moves up the scale as the temperature rises. It is necessary to have standard temperatures. The temperature at which water freezes is a fixed temperature and is used to graduate the thermometer. The temperature at which water boils is another temperature which is fixed if the atmospheric pressure is fixed. If, however, the atmospheric pressure is above normal the boiling-point is a little higher: this is because the water has to be raised to a higher temperature for the steam to push back the greater pressure of the atmosphere. Similarly, if the pressure is low, the boiling-point is low. Up high mountains the atmospheric pressure is low, because there is a lesser thickness of air pressing down, and water boils at a much lower temperature than usual, so that it is difficult to make good tea. The temperature, then, at which water boils at a particular fixed pressure is taken as another standard temperature.

1) 2) 3) 4)

Comprehension Check: Correct the wrong information (Part I) All solids and liquids expand as their temperature rises and there are no exceptions from this rule. The invar thermometer is widely used all over the world. If the pressure is low the boiling-point is high. Up high mountains water boils at much higher temperature than usual, so that we can make good tea.

II There are different temperature scales in use. The one used in all scientific work is the centigrade scale, on which the temperature of melting ice is called 0 0 C, and the temperature of water boiling at standard pressure is called 100 o C. The space on the stem between 0 o C, and 100 oC, is divided into a hundred equal divisions. The scale is also called the Celsius scale, after the Swedish astronomer Celsius, who first put it forward, so that C. can stand for this name as well as for centigrade. On the Fahrenheit scale, the freezing-point is called 32o F, and the boiling-point 212o F., so that 180 Fahrenheit degrees correspond to 100 centigrade degrees. This means that 0 o F. is below the freezing-point and equal to – 17.8 o C. There are other forms of thermometer depending on expansion. If two pieces of metal which expand unequally are fastened side by side and the strip is heated, then the fact that one side becomes longer than the other causes the strip to bend. This bimetallic thermometer is sometimes used. More important, however, is the gas thermometer. The volume of a gas depends not only upon the pressure, but upon the temperature. If the temperature rises and the pressure is kept constant, the gas expands: if the volume is to be kept constant, the pressure must be increased. There are gas thermometers based upon both principles : in the constant-pressure gas thermometer the change of volume measures the temperature, in the constant-volume gas thermometer it is the change of pressure. The gas thermometer is not used for ordinary temperature measurements, but it is the standard for accurate temperature. The gas thermometer finally checks standard mercury and other thermometers.

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III In imagination we can go to extremely high temperatures, but we cannot go to unlimitedly low temperatures. There is a definite lower limit to the temperature scale, called the absolute zero: it is 273 o C. below the freezing-point of water, or – 273o C. Modern workers have got very close to this absolute zero in the laboratory. There is practically no limit to the height that temperature can reach: the highest temperature in our hottest furnaces is extremely low compared to the temperature in the interior of stars or that reached for a moment in the explosion of atomic bombs, when the breaking of atoms is in question. On the other hand, the lower the temperature the less the motion of atoms and molecules, but this motion cannot diminish to less than nothing at all. There cannot be a temperature lower than that at which all the particles are at rest, and it is this temperature that is the absolute zero. At the absolute zero gases cannot exist, and all the familiar gases have solid form well before the absolute zero is reached. IV Heat is a form of energy. There is no friction without the generation – that is, the birth – of heat, and the heat generated is equivalent to the work done against friction. The establishment of this was a most important step and the statement that heat is a form of energy constitutes what is known as the first law of thermodynamics. The unit of heat is called calorie, and is the heat required to rise the temperature of 1 gramme of water by 1 o C. What is called the mechanical equivalent of heat is the amount of work – i.e., of energy – required to produce 1 calorie. To raise the temperature of 1 gr. of water by 1o C. takes the work required to lift 1 kg. Through 43 cm., or to raise the temperature of 1 pound of water by 1o F. needs about the work required to lift 79 pounds through 10 feet or 790 pounds through 1 foot. It is not only possible to convert work into heat, it is also possible to convert heat into work, as every steam-engine demonstrates. Here the rate of exchange is the same: the heat of 1 calorie, if it can be turned into work, suffices to lift 1 kg through 43 cm. But there is a special law that governs the conversion of heat into work, and this we must now consider. Heat can never be converted into work unless there is a difference of temperature. There is a law which states that it is not possible to construct a machine which will continuously furnish useful work by taking heat from a body no warmer than its surroundings. This is called the second law of thermodynamics. To turn heat into work, then, we must have a difference of temperature, a body hotter than its surroundings. In any steam-engine, which we may take as an example, we have a boiler, very hot, and a condenser, relatively cold. The fraction of the heat that we can use is fixed by the difference of temperature – the greater this is the better. The sum always works out right: heat taken from boiler equals heat turned into work plus heat returned to condenser. That is the Conservation of Energy. If we could have a condenser at the absolute zero of temperature we could, theoretically, turn all the energy of a hot body into work, but this is, of course, not practically possible. The best we can do is to keep the condenser at something near the temperature of the surroundings, by cooling it with the coldest water available. Comprehension check 1) Which temperature scales are widely used in the modern world? 2) What is the main principle of Celsius scale? (Fahrenheit scale?) 3) Which scale is used in Russia? (Gr. Britain, America)? 4) What kinds of thermometers do you know? Which is the most accurate? 5) What is absolute zero?

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6) Is there any limit to the height that temperature can reach? 7) What is the 1st law of thermodynamics? 8) Is it possible to convert work into heat and on the contrary, work into heat? What is the main condition? 9) What is the 2nd law of thermodynamics? 10)What is the conservation of energy? V There are three ways in which heat may pass from one point to another, termed conduction, convection, and radiation, all three of which are observed in everyday life. If one part of a solid be made hot, the heat passes along it and raises the temperature of the other parts. This is particularly noticeable with metals: with an all–metal pot containing a hot liquid the handle gets hot, and if one end of a metal rod be heated in any way the other end soon becomes hot. The effect is particularly strong with copper and silver, less noticeable with lead. A measure of the effect of heat conduction is given by the quantity known as thermal conductivity. This is the amount of heat, in calories, passing through unit area (1 square centimetre) when the temperature falls 1 o C in a distance of 1 centimetre. Not only do metals conduct heat, but so do all other substances. For liquids and gases there is a different method by which heat can pass from one point to another. Hot liquid can move bodily from a hotter place to a colder place: even if it is not stirred in any way the hotter liquid, having expanded, and so become lighter, will move up through the colder liquid, carrying heat with it. This process is known as convection and takes place in gases as well. It is a common fact of observation that hot air rises from a hot body. Whenever a liquid or a gas is heated from underneath convection is very active in causing the passage of heat. Liquids and gases conduct heat also, but very badly. There are certain solids which conduct heat particularly badly, owing to the fact that they consist mainly of tiny cells in which air is imprisoned so that it cannot circulate and convey heat by convection. An example of such a very poor conductor of heat is balsa wood, which is extremely light. The heat of the sun does not reach us by conduction or convection, but by the third method, radiation. Rays from the sun, which have travelled through 92 million miles of empty space before reaching the earth’s atmosphere, convey heat to every body on which they fall. The light rays, which are partly absorbed by the surface, are responsible for some of the heat, but more is conveyed by rays that behave like light rays but cannot be seen, called infra-red rays. III Grammar: Comparatives and Superlatives. Use: a) The comparatives and superlatives of words with - one syllable are formed like this: green – greener – the greenest – with three syllables: beautiful – more beautiful – the most beautiful b) There are a few reliable rules for words with 2 syllables – you must learn them individually. c) Words ending in -‘y’or -‘ow’are usually written like one-syllable words. Words ending in –‘ful’take ‘more’and ‘most’. d) Note: -y – ier – iest

IV Writing:

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1. Write the comparatives and superlatives of these words; what are irregular? Strange Shy Difficult Dirty narrow suitable Helpfulgood bad Faraccurate low Hotnoticeable little 2. Make up a list: great, tiny, fine, huge, minute, large, little, vast, high, low. Big Small – 3. Write a short summery of the last (5) part of the text; think of the points: conduction, convection, radiation. Think of a title of this part of the text.

Unit 6 I Pre-reading task: 1. Check up the meaning and pronunciation of the following words; Guess the meaning of the words underlined: Verbs: carry out, prove, refract, arrange, allow, fall, bend (bent, bent), mix, overlap, occur, be due to smth., hang,. Nouns: prism, ray, hole, beam, grade, rug, mixture, rainbow, refrangibility. Adj: complicated, definite, pure, neighbouring, artificial. II Grammar: Past Simple Active/ Passive; (Signal words: last… , … ago, then, yesterday, when… ) Active: (I did, I was, they were, I could, I had to do); Note: No ‘did’ with ~ to be, ~ could! 1) Write the verbs with the past tense: When I (be) young I (go) to England. There I (live) in London. I (be) rich and so I (must) buy things that (not/be) too expensive. I usually (buy) the cheapest things I (can) get. I never (take) a taxi, I usually (walk). The people (be) very kind and (help) me. I (meet) very good friends in London. After a few months I (begin) to work as a shop assistant. That (be) very interesting. Every day I (see) and (hear) new things. Two years ago I (come) home to Russia. Passive: (be + V.3) Use: in the passive, the object becomes the subject: The Chinese (subject) invented gunpowder (object) Gunpowder (subject) was invented by the Chinese. 1. a) b) c) d) e) f) 2.

Rewrite these sentences in the passive: The thief opened the door. He found the gold watch. He took the computer. He stole everything. The butler called the police. The police caught the police Rewrite the sentences in Present Simple (active/passive):

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III Reading: Read the text; Find out the examples of passive forms. Light Three hundred years ago Isaac Newton carried out a fundamental experiment with the prism. Newton’s experiment proved that a ray of a particular spectral colour was refracted by a particular amount by a prism of a particular glass. Newton proved this by making a small hole in the screen and arranging its position so as to allow one colour of the spectrum only. This beam fell on a second prism and measurement showed that this prism refracted it by exactly the same amount as the first prism had done. The true physical difference between the different spectral colours was in this way demonstrated by a difference of the amount by which they were bent by the glass, called a difference of refrangibility Before Newton it was believed that white light, the natural light, was simple and that all colours were complications. Newton showed that white light was the complicated thing, made up of spectral colours blending into one another, and that each spectral colour and grade of colour had a definite refrangibility. Thus an ordinary coloured body, say a red rug, is not red because it adds something to the white light falling on it, but because it absorbs all the spectral colours of the white light except the red, which it lets go back. If we mix yellow and blue paint we get a green paint, because the yellow, which in the case of paints is not a pure spectral colour, absorbs all the spectral colours, except the yellow and some of the neighbouring green. While the blue, which is likewise not a pure spectral colour, absorbs all the spectral colours, except the blue and some of the neighbouring green. Only the green, then, is left unabsorbed by the mixture. It follows that a red flower will look black if illuminated by bright blue light, since it absorbs all the blue end of the spectrum. Ordinary colours are called subtraction colours. If we throw a yellow beam and a blue beam of light so as to overlap on a piece of white paper we get a true addition colour, which is whitish, and not at all green. It is a strange fact that a white colour can be produced by the addition of two spectral colours, for instance orange and blue. Such colours are called complementary colours. Most colours that occur in nature are not pure spectral colours: thus natural yellow - say the yellow of the flower – contains some green and often some red and orange; different browns are mixture of red, orange, and yellow spectral light in different proportions. The colours of the rainbow are due to the different refraction of the different colours that make up sunlight by a widespread cloud of tiny water- drops hanging in the skies. On a clear sunny day, if you stand with your back to the sun and get a cloud of drops made well up in the air in front of you by squirting water, you can see an artificial rainbow.

a) b) c) d)

Comprehension check: These are the answers. What are the questions? When … … … … … … … … … … … ? (3 hundred years ago) What … … … … … … … … … … … ? (He proved that a ray of particular spectral colour was refracted by … … … ) What … … … … … … … … … … ? (The true physical difference between the different spectral colours was … … ..) … … … … … … … … … … … … ? (No, white light was the complicated thing)

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IV Writing: 1. Write the sentences in right order: 1. Before Newton it was believed that white light was simple. 2. On a clear sunny day you can see an artificial rainbow. 3. Newton showed that white light was the complicated thing. 4. The colours of the rainbow are due to the different refraction of the different colours. 5. Most colours that occur in nature are not pure spectral colours. 6. If we mix yellow and blue paint, we get a green paint, because the yellow is not a pure spectral colour. 7. Complementary colours can be produced by the addition of two spectral colours. 8. Ordinary colours are called subtraction colours. 9. If we throw a yellow beam and a blue beam of light so as to overlap on a piece of white paper we get a true addition colour. 2. Give a short summery of the text. Unit7 I Pre-reading task: 1. Check up the meaning of the following words: Verbs: detect, convey, pump out, hang up, vibrate backwards and forwards, pass through, note, reflect, detect, judge, register. Nouns: wave, bell, ticking, vessel, particle, sight, lightning, thunder, reflection, cliff-face, wavelength, echo [ ], source, depth, shoal of fish, submarines [ ], apparatus, frequency. Adj: huge, glass, longitudinal, blank, flat, sharp, dry, satisfactory. Adv: completely, precisely. II Grammar: Present Perfect (Active/Passive) Active;( have/has + V.3) Use: a) expresses an action in the past – the experience as a part of someone’s life. e) ~ an action or state which began in the past and continues to the present. Passive:(has/have + been + V.3) Use: The rules for tense usage in the passive are the same as in the active. The Americans have made Diet Coke since 1982. (Active) Diet Coke has been made since 1982 (Passive) III Reading: 1. Read the text and find out the examples of Pr. Perfect (passive forms). Sound Sound, as detected by the ear, is the result of a wave passing through the air. Light travels in completely empty space, which can carry electromagnetic forces, but sound

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requires something material, a gas, a liquid, or a solid, to convey it. If there were a huge explosion on the moon, we should, of course, see it, but we should hear nothing. Long ago Robert Boyle proved that sound would not travel through empty space. He hung up a watch by a fine thread in a glass vessel, and showed that, when the air was pumped out, no sound of ticking could be heard, although it was plain before. He also arranged a bell so that it could be struck in a vessel, from which the air had been removed, with the same result That sound travels well through a liquid can be easily proved by putting the head under water in the sea, or in a river or lake. Men can hear distant horsemen by putting their ear to the ground, an example of sound travelling through a solid. Sound that we normally hear is, then, a longitudinal wave in air, which means that the particles are vibrating backwards and forwards in the direction in which the wave is travelling. Sound travels very slowly compared to light the rate at which it passes through air depends somewhat on the temperature, being greater for higher temperatures. Thus at 80 o F. (26.7o C.) the velocity in dry air is 1141 feet per second; at freezing point, 32o F (0o C.), it is 1087 feet per second. One can judge the distance, in feet, of a thunderstorm, by noting the seconds between the sight of the lightning and the first sound of the thunder, and multiplying the number by 1100. Thus an interval of five seconds corresponds to a distance of 5500 feet, about a mile. Sound travels through liquids much more rapidly than through air. It travels more rapidly still through metals. The velocity through the earth naturally depends upon the nature of the materials. Sound, like light and all wave motions, can be reflected, but for good reflection of ordinary sound we need a flat surface several feet across, a blank wall or a flat cliff-face, for instance. This is because the reflecting surface must be several wavelengths across if the reflection is to be satisfactory. Any sharp sound, such as that of clapping the hands, made in front of such a surface will be heard again after a short interval – the so called echo. The interval is the distance there and back from the clapping listener to the reflecting surface, divided by the velocity of sound, so that for an interval of 1 second, the listener, who is also the source of sound, must be about 550 feet from the surface. Important practical use has been made of the reflection of sound in recent years. At sea the so-called ‘sounding’is used to find the depth of the sea at any point. A like method has even been used for detecting and measuring the depth of a shoal of fish, the sound being reflected from the immense numbers of fish. Sound reflection has also been used for the detection of submarines. In all cases, sound of very high frequency, so high that it cannot be heard – that is, of very short wavelength – is used, in order to get sharp reflection. Needless to say, the modern apparatus used can detect and register the arrival of such waves very precisely. Comprehension check: 1) 2) 3) 4) 5) 6) 7)

What is sound? Can sound travel in completely empty space? What experiment did Robert Boyler carry out to prove his idea? Sound travels very slowly compared to the light, doesn’t it? How can we judge the distance of a thunderstorm? What do we need for good reflection of ordinary sound? What is echo? How is the sound reflection used for more practical purposes?

IV Writing: 1. Give a short summery of the text.

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Unit 8 I Pre-reading task: 1. Check up the meaning of the following words: Verbs: commemorate, wind (wound, wound), connect, flow, find, found. Nouns: significance, current, coil, wire, galvanometer, circuit, magnet, transformer, dynamos, armature, voltage, essence. Adj: rotating, alternating. II Reading: Electromagnetic induction In 1831 Faraday made a discovery that is of fundamental significance for electronic theory and is also the basis of practically all electrical engineering. It’s, in fact, so important that in 1931 a great celebration was held in London to commemorate the discovery. The essence of this discovery was that a magnetic force could produce a current. Faraday’s experiment was carried out in the following way: on the iron ring were wound two separate coils of insulated wire, one being connected to a galvanometer and the other to a battery. There was a key in the battery circuit that could make and break the electrical contact, so as to cause a current to flow or to make it cease flowing. What Faraday found was that when a steady current was flowing in one coil, no current flowed in the other coil, but that the breaking or making of the current in one coil gave rise to a momentary current in the other coil. In this ring experiment the current makes an iron ring a magnet. The experiment shows that any change of the magnetic force passing through a coil produces a current in that coil, as can also be demonstrated very simply with a coil connected to a galvanometer. Increase of the magnetic force through a coil leads to a current in one direction, decrease of force to a current in the other direction. This fundamental phenomenon is called electromagnetic induction. Faraday’s iron ring is the simplest form of the modern transformer, which transforms one alternating current into another alternating current of a different voltage. Modern dynamos, which are machines for producing large currents, are all founded on this electromagnetic induction. The rotating construction of iron surrounded by coils of wire is called the armature of the dynamo. The more current that is being taken from the dynamo, the more mechanical power is required to keep the armature turning. Nothing for nothing is the rule in physics.

Comprehension check: 1) When did Faraday make the discovery of the phenomenon of electromagnetic induction? 2) What was the essence of that discovery? 3) How was Faraday’s experiment carried out?

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4) 5) 6) 7) 8)

What did Faraday find out? What is electromagnetic induction? What is dynamo? What is armature? What is the fundamental rule in physics?

III Writing: 1. Give a short summery of the text.

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С о с тави тель: Греко ва Ольга Ана то льевна Реда кто р: Буни на Т.Д .