The Temperature Scales

Read and translate the text

Answer the questions

EXERCISES

1. How do molecules behave in the gaseous state?

2. When was the progress in experimental techniques achieved?

3. What did Otto von Guericke invent and what did he demonstrate with his

device?

2. Give synonyms:

constant, to observe, technique, advance, instrument, continual, to watch, method,

progress, device.

3. Give antonyms:

constant, simple, dilute, early, involve, unite, dependent, individual, complex,

concentrated, independent, common, late, alternative, evolve, separate

4. Read and translate the sentences:

1. Experimental techniques dealing with gases were developed in the sixteenth and the seventeenth centuries. 2. Investigating the properties of gases E. Torricelli invented the mercurial barometer. 3. Having prepared everything for the laboratory work, the students began experimenting with chemicals. 4. Having considered the problem, we arrived at a definite conclusion. 5. The problem involved deals with inert gases. 6. The discovery of the instrument concerned belonged to Torricelli.7. The existence of rarefied atmosphere may be proved by the device concerned. 8. The question involved will be discussed later. 9. In order to determine whether a compound concerned is organic it is frequently sufficient merely to heat it.

The scientist finds two temperature scales the most convenient. They are the centigrade (or Celsius) scale and the absolute (or Kelvin) scale. Many engineers use the Fahrenheit scale (currently in the United States). The oldest thermometric scale was devised by Gabriel Fahrenheit, a German instrument-maker. In 1714 Fahrenheit invented the mercury-in-glass thermometer. Zero degree on the Fahrenheit scale was selected as the lowest temperature obtainable with a mixture of common salt and water. For a higher reference point he selected the body temperature of a healthy man. The interval between reference points was divided into 96 equal parts. The centigrade scale was devised in 1742 by the Swedish astronomer Anders Celsius, who reasoned that water would make an excellent primary thermal standard. For convenience, he established the zero point on his scale at the freezing point of water and the 100-degree mark at its boiling point. Both temperatures are measured at one atmosphere pressure on air-saturated water. The relationship is (°F) = 1.80 x (°C) + 32.0.

Lord Kelvin in 1848 used his knowledge of the behaviour of gases to predict a temperature that would represent the lowest energetic state in which matter could exist. Theoretical predictions based on thermodynamics indicate that absolute zero can never be attained. Temperatures (T) on the absolute scale are measured in degrees Kelvin (K) in his honour. The size of the degree is identical with that on the centigrade scale. The relationship is (°K) = (°C) + 273.16.

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