Прочтите текст про себя (контрольное время чтения—4,5 минуты). Temperature Scales
If two objects are placed in contact with one another, thermal energy may flow from one objcct to the other one. Temperature is the quality that determines the direction in which thermal energy flows — it flows from the objcct at higher temperature to the objcct at lower temperature.
Temperatures are ordinarily measured by means of a thermometer, such as the ordinary mcrcuiy thermometer, consisting of a quantity of mercuiy in a glass tube. The temperature scalc used by scientists is the centigrade or Celsius scale; it was introduced by Anders Celsius (1701- 1744), a Swedish professor of astronomy, in 1742. On this scale the
temperature of freezing water saturated with air is 0°C and the temperature of filing water is 100°C at 1-atm pressure.
On the Fahrenheit scale, used in everyday life in English-speaking countries, the freezing point of water is 32°F and the boiling point of water is 212°F. On this scale the freezing point and the boiling point differ by 180°, rather than 100° of the ccntigrade scalc. The Fahrenheit scalc was devised by Gabriel Fahrenheit (1686-1736), a natural philosopher who was born in Danzig and settled in Holland. He invented the mercury thermometer in 1714; before then, alcohol had been used as the liquid in thermometers. As the zero point on his scale he took the lowest temperature he could obtain, produced by mixing equal quantities of snow and ammonium chloride. His choice of 212° for the boiling point of water was made in order that the temperature of his body should be 100°F. The normal temperature of the human body is 98.6°F; perhaps Fahrenheit had a slight fever while he was calibrating his thermometer.
To convert temperatures from one scale to another, you need only remember that the Fahrenheit degree is l(K>/|$o or % of the centigrade degree, and that 0°C is the same temperature as 32°F.
Another absolute scale, the Rankine scale, is sometimes used in engineering work in the English-speaking countries. It uses the Fahrenheit degree, and has 0°R as the absolute zero.
Упр. 3. Передайте основное содержание текста в нескольких предложениях.
Упр. 4. Составьте план текста.
Упр. 5. Прочтите предложения и скажите, соответствуют ли они содержанию текста. Если нет, исправьте их.
1. Temperature determines the direction in which thermal energy flows when the two objects are in contact. 2. Thermal energy flows from die hotter object to the eolder one. 3. Temperature is measured by means of thermometers using different temperature scales. 4. The inventor of the Fahrenheit scalc was German. 5. Fahrenheit devised alcohol thermometer.
6. Only the Fahrenheit scalc is used in the English-speaking countries.
7. The temperature of the boiling water is 100 degrees centigrade. 8. The inventor of the centigrade scalc was an outstanding physicist.
Упр. 6. Найдите в тексте и переведите на русский язык предложения в которых дано описание того, как перевести значение температуры с одной шкалы на другую.
Section III
Ex. 1. Respond to the following using the verbs to listen and to hear.
1.1 didn't hear what he said, did you? 2. What kind of music do you like to listen to? 3. It seems to me that somebody is calling me, do you hear? 4.1 don't like to listen to the radio and what about you? 5. The teacher
is speaking so quietly, 1 can hardly hear him. 6. Usually, small children like to listen to fairylalcs before going to bed and what about your sister? 7. The bell is ringing, the lesson is over, but the tcachcr seems not to hear.
Ex. 2. Translate the sentences into English.
1. Кажется, телефон звонит, вы слышите? 2. По-моему, что-то упало, вы слышали? 3. Мой брат может целый вечер слушать классическую музыку, а я люблю слушать джаз. 4. Здссь очень шумно, я почти ничего не слышу. 5. Лекция довольно интересная, а ее почти никто не слушает, б. Он слушаст новые записи. Кажется, они ему нравятся. 7. Не слушайте его, он сам не знает, что говорит. 8. Я слышал, наш руководитель уже приехал из Москвы.
Ex. 3. Make up short dialogues according to the model.
Model: — A statement.
— A statement.
— A question.
| Example: |
— An answer.
— I hear some students are engaged in scicntific work.
— And as far as I know, almost every undergraduate does a more or less serious research.
— Who helps them?
— Their supervisor.
Ex. 4. Give detailed answers to the following questions: 1. What is temperature? 2. In what way can the boiling point of a liquid be determined? 3. What arc the factors that affcct the boiling point? 4. What units of pressure arc used in chcmistiy? S. What temperature scales do you know?
Ex. 5. Discuss the following topics:
1. The Boiling Point as a Physical Factor.
2. Means of Measuring Pressure.
3. Temperature Scales.
WHAT IS IT?
An instrument for measuring the pressure of the atmosphere.