Text 2. Systems of measurement

Key terms: measurement, the Common (English) system, themetric (international) system, the MKS system, the CGS system, value, convert, unit of distance, metre, aver­age time, mean solar day, second, mass, gram, pound, kil­ogram, force, energy.

There are two main systems of measurement in use today: the English system of units (or as it is after called the Common system of units) and the metric system of units (the SI). Except for the United. States and Great Britain nearly all the nations of the world use the metric system. Although the English system of units is still the official system in the US, American scientists use the metric system almost exclusively. The value of the met­ric system is that its various units possess simple and logical relationship among themselves, while in the Common system 1 mile is equal to 1760 yards; 1 yard is equal to 3 feet; 1 foot is equal to 12 inches. In the latter system converting one unit into another is a hard and monotonous job.

In the metric system the main unit of distance is the metre. Other units of distance are always obtained by multiplying the metre by 10 or some power of 10. Thanks to our system of writing this means that conversions of one unit to another with­in the metric system can be carried out by shifts of a decimal point.

Time is a physical concept and its definition is related to certain laws of physics. The laws of physics say that the aver­age time it takes for the sun to move from its noon position one day to its noon position the other day is called the mean solar day. The basic unit of time used in both the English and the metric systems is the second. It is equal to 1/60th. of a minute x l/60th of an hour x l/24th of a day = 1/86,400th of a mean solar day.

Being also a physical concept mass must be defined in terms of certain laws of physics. In the metric system the unit of mass was originally defined as the amount of mass contained in 1 cubic centimetre (cc) of water at a specified temperature and pressure. This amount of mass is called the gram. Thus the density of water is conveniently one gram per cubic centimetre. In the English system the unit of mass is the pound, one kilo­gram being equal to 2.204 pounds of mass. We shall use the abbreviations gm for gram, kg for kilogram and lb for pound.

In physics the quantities such as force and energy are usu­ally measured either in meters, kilograms and seconds, or in centimetres, grams and seconds. The former system is called the MKS system and the latter the CGS (the Gaussian) system. Both of these metric systems are used in scientific papers.

Vocabulary notes

expect for крім, не враховуючи

value, n величина, значення

to possess relationship стосуватися, мати стосунок

to be equal to дорівнювати

obtain, v отримувати

multiply, v множити

within, prp в межах, у рамках

carry out, v здійснювати

shift, n зсув, зміщення

to be related бути зв’язаним

decimal point десяткова кома (крапка)

average, adj середній

in terms of мовою, в термінах, з позицій

certain, adj певний

specify, v визначати

TASKS

I. Pronounce these international words and translate them:

'system, of'ficial, mo'notonous, con'vert, 'concept, abbrevi'ation, vary, 'logical, mile, 'distance, metre (Brit.) - meter (Amer.), po'sition, 'basic, 'second, mass, con'tain, 'origin, 'cubic, centi'metre

II. Read and translate these words, analyse to what part of speech they belong;

to exclude — exclusive - exclusively — exclusion

convenient — conveniently — convenience — inconvenience relate - relation — relationship – correlation

value - valuable — invaluable - evaluate — evaluation accurate - accurately - accuracy - inaccurate.

III. Fill in the blanks with accurate (adj), accurately (adv), accuracy (n) in the following sentences and ask questions about the missing parts of the sentences.

1. We usually measure physical quantities ... . 2. They re­ceived ... results. 3. The ... of the measurements surprised us.

4. They will carry out the experiment with ....

IV. Which noun-forming suffix will you use to form nouns from the following verbs. If necessary, consult the Table of the word-forming suffixes.

to discover, to act, to solve, to express, to observe, to measure, to define, to move, to suppose, to explain, to convert.

V. Keep in mind the following suffixes of nouns: -or, -er, -ion, -tion, -sion, -ment, -ance, -ence, -ity. Write the words with these suffixes. Give the verbs corresponding to these nouns and translate both the verb and the noun into Ukrainian.

VI. Translate the following sentences into Ukrainian paying attention to different meanings of the word time:

time раз, період, час

for the first time вперше

at times іноді, часами

times помножене на

1. Check the time of the experiment. 2. The production of the plant has decreased by more than ten times since 1991. 3. The Venus at times comes rather close to the Earth. 4. This value is equal to N times R.

5. They usually check the results many times.

VII. Answer the questions on the text

1. What is the definition of time related to? 2. How many systems of measurement are there in use today? 3. Which sys­tem do nearly all nations of the work I use? 4. Which countries use the English system of measurement? 5. What is the official system in the USA? 6. The MKS and CGS system belong to two different systems of measurement, don't they?

PROBLEMS

1. Express your height in the English system of measurement.

2. A rocket attained a height of, 300 kilometres. What is the distance in miles?

3. Astronomical distances are so large compared to terrestrial ones that much larger units of length are used for easy comprehension of the relative distances of astronomical objects. An astronomical unit (AU) is equal to the average distance from the earth to the sun, about 92,9x10⁶ miles. A parsec is the distance at which one astronomical unit would subtend an angle of 1 sec of arc. A light year is the distance that light, travelling through a vacuum with a speed of 186,000 miles/second (/-per), would cover in one year.

1. Express the distance from the Earth to the Sun in parsecs and in light years.

2. Express a light year and a parsec in miles.

Keys to the crossword:

Across: 5. Salinger, 9. foreign, 10. glad, 11. miss, 13. supper,

15. are, 17. verb, 18. mine, 19. in, 20. neat, 21. stay.

Down: 1. star, 2. English, 3. read, 4. remind, 5. sorry, 6. arriv­al, 7. letter, 9. farewell, 12. mean, 14. party, 15. did.

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