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Assignment 3. Translate the words, their derivatives into Russian and learn them



 

to behave – behaviour; to boil – boiled – boiler – boiling; caloric – calorific – calorification – calorifics; certain – certainly – certainty; to conduct – conduction – conductive – conductivity; to collide – collision; to compress – compressed – compressible – compression – compressor; to develop – development; to expand – expansion – expansive; to explain – explanation; to measure – measure – measured – measureless – measurement – measurer; to move – movement – moveless – mover; to quantify – quantity; science – scientific – scientist; to state – statement; to use – use – useful – useless – user; to weigh – weight – weightless – weightlessness.

 

 

Assignment 4. Read and translate the text:

 

TEXT 11. WHAT IS HEAT?

 

What makes one thing hot and another cold? What do the terms “hot” and “cold” really mean?

Scientists are known to have worked for a long time to find an answer to the last question. They decided at last that the manifestation of heat was caused by a weightless substance or fluid called “caloric.” It seemed to be weightless because the numerous experiments proved that it did not produce any increase in weight. To explain its behaviour was simple and easy. According to the caloric theory, a hot body contains more caloric than a cold one. Hence caloric was considered to pass from the former to the latter. How­ever, experience showed that certain heat effects could not be explained by the above theory, namely: the development of heat owing to friction as well as the changes of temperature during the compression or expansion of a gas. Nevertheless, the theory in question seemed to be the only possible theory until the beginning of the 19th century, or so.

Lomonosov was the first to state that heat phenomena were due to molecular motion. His statement proved to be correct years after his death.

At present, we know heat to be a form of energy. Besides, we are quite familiar with the fact that all substances are made up of little particles called molecules. These are so min­ute that a single drop of water, for example, is assumed to have millions of them. Although a drop of water left on the table may seem to be at rest, everyone of its molecules is really moving about, colliding with other molecules, pushing them, and changing direction. Of course, while one molecule is travelling, all the other millions of molecules in the drop of water are doing the same thing. They are travelling in various directions, colliding, pushing other molecules and jumping away from each other.



What process takes place when we place a kettle full of cold water on the fire, in other words, when we want to heat water? The molecules begin to move much faster then, so that every time there is a collision, they jump away from each other much farther than they did before. As a result, the drop of water becomes larger, that is to say, it expands. In scientific language this property is called expansion.

The much faster molecular movement makes the water first warm and then hot. On taking our kettle from the fire, we expect the molecules to slow down, and indeed the water begins to get cold. When our tea is said to be "hot" it really means that its molecules are travelling very fast. On the contrary, when the tea is cold, they are moving more slowly.

Although heat and temperature are certainly connected, it is necessary to understand the difference between them. To show that similar quantities of heat may produce very different effects in different substances, is not difficult at all. Placing a needle on the fire at the same time as a kettle of cold water, we find that the needle is red-hot before there is any marked difference in the temperature of the water.



We must say here that a red-hot needle receives far less heat than a kettle full of boiling water but its temperature is nevertheless much higher. On the other hand, if we place it in the boiling water, although the latter is certain to possess far more heat than the former, the needle gives up heat to the water and not vice versa. When two bodies at different temperatures are brought into contact, we expect the warmer body to get cold while the colder one will be warmed. In this case, heat is said to flow from one body to the other by conduction.

As for expansion caused by heating, it is useless and even dangerous in some cases while in others we cannot do without it. For example, to measure temperature one employs a ther­mometer. In order to obtain a definite scale of temperature, we make use of the fact that bodies generally expand on being heated.

One must remember that heat may produce a change of state without changing temperature.

 

Notes to the text:

1) at last – наконец

2) according to – согласно

3) owing to – благодаря

4) as well as – а также

5) in question – о котором идет речь

6) the only – единственный

7) or so – приблизительно

8) due to – благодаря

9) at present – в настоящее время

10) to be familiar with – знать ч-л.

11) a single drop – одна капля

12) at rest – в состоянии покоя

13) the same – тот(же) самый

14) to take place – происходить

15) in other words – другими словами

16) every time – каждый раз

17) farther – дальше

18) as a result – в результате

19) to take from – снимать, убирать

20) to slow down – замедлять(ся)

21) on the contrary – наоборот

22) at all – вообще, совсем

23) at the same time – в то же самое время

24) far less – гораздо, значительно меньше

25) on the other hand – с другой стороны

26) to give up – отдавать

27) vise versa – наоборот

28) as for – что касается

29) to do without – обходиться

30) in order to – чтобы

31) to make use of – использовать, употреблять

 

 


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