Exercise 2. Read the following words. Translate them.

kinetic, molecule, i.e., pound, iron, mechanical, inability, contemporary, finally, phenomenon, century, raise, experiment, require, define, theory, weight, amount, case, suppose, fluid, friction, average, increase, iron, scientist, numerous, content.

 

Exercise 3. Translate the words into English:

період, вага, речовина, рух, доводити, проте, озеро, внутрішній, рідина, пояснювати, руйнувати, середній, визначати, перетворювати.

Exercise 4. Answer the questions:

1. What is heat?

2. What does heat usually cause?

3. What is a substance made up of?

4. Does heat always produce a change of temperature?

5. Was heat considered to be a form of energy a century ago?

6. What did Lomonosov state?

7. Who was among the first to state that heat phenomena were due to the motion of molecules?

8. How long did the caloric theory exist?

9. What is the unit of heat?

10. How is the caloric defined?

Exercise 5. Give the synonyms to the words:

increase, suppose, know, call, heat, great.

 

Exercise 6. Give the antonyms to the words:

The first, motion, carefully, fluid, heat, present-day, raise

 

Exercise 7. State if the following sentences are true to the fact or false. Correct false statements.

1. Today heat is known to be a form of energy.

2. Heat usually causes a decrease in the average kinetic energy of the random motion of molecules.

3. The substance called „caloric” was believed to pass from a colder body to a hotter one.

4. A hot body contains more of the heat fluid than a cold one.

5. The caloric theory of heat accounted for almost everything that was known about heat.

6. Great scientist Lobachevskiy was among the first to find and state that heat phenomena were due to the motion of molecules.

7. Lobachevsiy’s theory laid the foundation for the present-day molecular-kinetic theory at heat.

8. The true calorie is defined as that quantity of heat which will raise the temperature of 1gram of water from 19.5 to 20.5 C.

 

Exercise 8. Write out the keywords and phrases and make up a plan.

Exercise 9. Retell the text.

 

Part B.

Exercise 1. Read and translate the text.

Heat and Temperature.

As we have just noted, there was a time when heat was supposed to be a sort of substance or fluid which flowed from a body of high temperature to one of lower temperature. That substance was given the name "caloric". At present, we know heat to be a form of energy and to be capable of performing work. Heat may be converted into mechanical energy and heat, in its turn, is generated when mechanical motion is destroyed by friction.

An object is said to be hot if its temperature is higher than that of our body, or cold if its temperature is much lower. If a hot body is brought into contact with a cold one, the hot body will cool and the cold body will become warmer. We explain it by the fact that the hot body has transferred some amount of heat to the cold one. If two bodies A and B are brought into contact and heat is transferred from A to B, we say that A is at a higher temperature than B, or that A is hotter than B.

Hot and cold are not very definite terms, nor are our temperature sensations very accurate. A room may seem to be warm when one enters it after being out in the cold. On the other hand it may seem to be cold after one has been near a hot furnace.

Our temperature sensations are found to be neither accurate nor reliable and the differences of temperature are generally defined by other means.

To measure temperature it is necessary to choose some kind of temperature scale. This may be done by means of some substance which changes with temperature changes. For example, a liquid such as mercury is known to expand when it is heated. Therefore, its change of volume due to heating is often used to measure the change of temperature (this is the principle the mercury thermometer is based upon).

 

Exercise 2. Read and translate the following words. Make up sentences using these words.

Amount, accurate, furnace, unreliable, liquid, mercury, thermometer, notice, different, measure, therefore, finger, definite, show, sensations, substance, know.

Exercise 3. Answer the following questions.

1. What does this article deal with?

2. What is heat?

3. Is heat capable of performing work?

4. When can you say that a body is hot?

5. Is heat a form of motion?

6. What happens when a hot body is brought into contact with a cold one?

7. Are out temperature sensations accurate?

8. Does mercury expand when heated?

9. What instrument is used for measuring temperature?

10. What principle is the mercury thermometer based upon?

 

Exercise 4. Translate the following sentence.

1. Відомо, що речовина складається з молекул.

2. Вважали, що теплород переходить від більш гарячого тіла до більш холодного.

3. Ми знаємо, що тепло це форма енергії.

4. Здається, температура води піднімається до 80⁰ С.

5. Відомо, що Ломоносов установив молекулярно-кінетичну теорію газів.

 

Exercise 5. Give equivalents of the words.

тепло, час, потік, тіло, речовина, форма, рух, руйнувати, тертя, пояснити, вищий, чашка, ртуть, читати.

Exercise 6. Form as many words as possible from the given below.

differ, accurate, worm, measure, high, object, transfer, place, rely.

 

Exercise 7. Annotate the text using the phrases.

The subject of this text is …; The author described …; The purpose of this article is …; It is pointed out that …; The author tells us about …; The text also discusses …; The next part of the text is devoted to …; Further the author describes … etc.

Part C.

Exercise 1. Read and translate the text.

Internal Energy.

A thermometer tells you the temperature of a substance but not the amount of internal energy in it. We know a cup of water at boiling point to be hotter than the water in a lake, however, the lake contains much more energy than the cup does. A large piece of ice will melt if thrown into the lake but only a small piece of ice could be melted by the hot water in the cup. The lake can give up more energy than the cup of water, even though the lake is at a much lower temperature. Thus, to measure the amount of energy given to an object, one must do more than simply determine its temperature change.

Here is another example to be considered. Let us take a small cup of boiling water and a large container also full of boiling water.

Both of them, certainly, have the same temperature. Thermometers would show the same reading for both the water in the cup and that in the container. They do not, however, contain the same amount of energy. It takes much more heat to make the water boil in the large container than it is required to boil the small cup of water. Again we see that the temperature of an object does not indicate the amount of energy to be contained in that object.

The amount of energy in a given body appears to depend on the nature of the body as well as on its size and temperature. Two bodies of equal weight but of dissimilar materials may have the same temperature but contain quite different amounts of energy. A 100-gram ball of iron at a given temperature is known to contain a smaller quantity of energy than does a 100-gram aluminium ball at the same temperature. „But what does the expression the same temperature really mean?” – one might ask. Two bodies are assumed to have the same temperature if when one of these bodies is placed in contact with the other one neither will transfer heat to the other.

A heated metal ball to be placed in contact with a piece of ice will transmit its heat to the piece of ice, that heat melting the ice. The fact that the metal ball loses heat shows that the two materials are not at the same temperature. If this metal ball is placed in the crucible of an electric furnace, the ball will gain sufficient heat from the crucible to make it melt. It shows that the crucible is much hotter than the ball. In any process where heat is transferred the body which is at a lower temperature is the one that gains heat.

To know the quantity of energy present in a body is very important, therefore, we shall shortly see what units are to be used for measuring the quantity of heat and how one can find the amount of energy which a given body contains.