Text 4. Systems of measurement

Metrology is the study of measurement. In general, a metric is a scale of measurement defined in terms of a standard: i.e. in terms of well-defined unit. Measurement is fundamental to most fields of science, including physics, chemistry and biology. Measurement is the estimation or determination of extent, dimension or capacity, usually in relation to some standard or unit of measurement. The process of measuring involves estimating the ratio of the magnitude of a quantity to the magnitude of a unit of the same type (e.g. length, time, mass, etc.). A measurement is the result of such a process, expressed as the product of a real number and a unit, where the real number is the estimated ratio. An example is 9 metres, which is an estimate of an object’s length relative to a unit of length, the meter. Unlike a count, or integer quantity of items that is known exactly, every measurement is an estimate that has some uncertainty. A count is a natural number and may be exact.

A system of measurement is a set of units which can be used to specify anything which can be measured. Some quantities are designated as fundamental units meaning all other needed units can be derived from them. In most systems, length (distance), weight and time are fundamental quantities; or as has been now accepted as better in science and engineering, the substitution of mass for weight, as a better more basic parameter.

Later science developments showed that either electric charge or electric current must be added to complete the minimum set of fundamental quantities by which all other metrological units may be defined. Other quantities such as power, speed are derived from the fundamental set; for example, speed is distance divided by time.

In antiquity, systems of measurement were defined locally, the different units were defined independently according to the length of a king’s thumb or the size of his foot, the length of stride, the length of arm and so on.

In the metric system and other recent systems, a single basic unit is used for each fundamental quantity. Often secondary units (multiples and submultiples) are used which convert to the basic units by multiplying by ten, i.e., by simply moving the decimal point. Thus, the basic metric unit of length is the metre or meter; a distance of 1.234m is 1234.0 millimetres, or 0.001234 kilometres.

The International System of Units (abbreviated SI) is the modern, revised form of the metric system. It is the world’s most widely used system of units, both in everyday commerce and in science. The SI was developed in 1960 from the metre-kilogram-second (MKS) system. There are two types of SI units, Base and Derived Units. Base units are the simple measurements for time, length, mass, temperature, amount of substance, electric current, and light intensity.

Derived units are made up of base units, for example density is kg/m³.

Before SI units were widely adopted around the world, the British systems of English units and later Imperial units were used in Britain, the Commonwealth and the United States. The Imperial units for distance, weigh and time are foot, pound and second. It is interesting to note that many Imperial units remain in use in Britain despite the fact that it has mostly switched to the SI system. Road signs are still in miles, yards, miles per hour, etc.

Examples of measuring instruments include the thermometer, speedometer, weighing scale and voltmeter. In order to measure accurately, measuring instruments must be carefully constructed and calibrated.

Exercise 39. Translate the following words and word combinations.

The metric system of measurement, decimal scale, light intensity, multiplication table, to a great extent, well-defined unit, units of measurement, real number, unit of length, fundamental units, basic parameter, science development, electric charge, amount of substance, electric current, carefully calibrate, derived units.

Exercise 40. Write all the derivatives of the following words and give their translation: revise, multiple, estimate, accept, define.

Example:

to measure – вимірювати

measure – міра

measurement – вимірювання

measurable – те, що можна виміряти

measurability – вимірюваність

measuring (device) – вимірювальний (пристрій)

Exercise 41. Match the English-Ukrainian equivalents.

electrical quantities consume scale multiplication measure capacity metrology unit of weight magnitude quantity electric power substance

речовина електроенергія кількість величина одиниця ваги метрологія ємкість вимірювати множення шкала, масштаб електричні величини споживати

Exercise 42. Identify by suffixes: a) nouns; b) verbs; c) adjectives; d) participles among the following words. Translate them.

Substitute – substitution – substituted;

determine – determination – determinative – determined;

designate – designation – designated;

quantify – quantification – quantity;

derive – derivation – derivative.

Exercise 43. Fill in the gaps with the words given in brackets below and translate the sentences.

(Metre, derived, foot, system, pound, power, speed, weight, set)

1. A system of measurement is a … of units which can be used to specify anything which can be measured. 2. Fundamental quantities in most systems are length, …, and time. 3. Other quantities such as …, … are derived from the fundamental set. 4. SI is the world’s most widely used … of units. 5. There are two types of SI units, Base and … units.

6. The Imperial unit for distance is the … and for weight is the … .

7. The … is the basic metric unit of length.

Exercise 44. Make the following sentences interrogative.

1. A system of measurement is a set of fundamental units. 2. Mass has been accepted as a basic parameter, instead of weight. 3. Imperial units were used in Britain. 4. Derived units are made of base units.

5. Many imperial units remain in use in Britain. 6. The SI was developed in 1960. 7. Scientists developed International System of Units from MKS system. 8. The ampere indicates the amount of electric current. 9. In future scientists will improve the system of measurement.

Exercise 45. Work in pairs. Make a question for each answer below with reference to text 4. Use the question word given in brackets.

1. A system of measurement is a set of units which can be used to specify anything which can be measured (What?) 2. All measurements have some degree of uncertainty associated with measuring instruments. (Why?) 3. Examples of measuring instruments include the thermometer, speedometer, weighing scale and voltmeter (What kind?) 4. In order to measure accurately, measuring instruments must be carefully constructed and calibrated. (Why?) 5. A measurement is a real number and is never exact. (What kind?) 6. Measurement is fundamental to most fields of science, including physics, chemistry and biology. (What?)

7. In the USA, commercial measurements are regulated by the National Institute of Standards and Technology. (Where?) 8. The metre was standardized as the unit for length after the French revolution. (When?) 9. The USA and the UK are in the process of converting to the SI system. (What?)

Exercise 46. Put the verbs in brackets into correct form of Present Simple, Past Simple, Present Perfect or Past Perfect.

1. Both the Imperial units and US customary units (derive) from earlier English units. 2. Prior to the widespread adoption of the metric system many different systems of official measurement (be) in use, many of these (remain) today, at least in part, in traditional use. 3. When the words (turn) to trade between city-states, better systems were needed to enable that mercantile activity. 4. Historically people (use) a wide range of units for the same quantity. 5. Some systems (change) to recognize the improved fundamental units. 6. Later science developments (show) that either electric charge or electric current must (add) to complete the minimum set of fundamental quantities. 7. Metric systems of units (evolve) since the adaptation of the first well-defined system in France in 1791. 8. Every measurement (be) an estimate that (have) some uncertainty.

Exercise 47. Rewrite the following sentences in Passive.

1. Nowadays people use the International System of Units.

2. Students easily derive all other needed units from fundamental units. 3. Historically people used a wide range of units for the same quantity. 4. In the metric system and other recent systems we use a single basic unit for each fundamental quantity. 5. The British mostly used imperial units. 6. While Americans have made some steps towards metrication, the customary units have a strong hold due to the vast industrial infrastructure and commercial development. 7. American scientists prefer the metric system, especially in technology and medicine. 8. It is necessary to calibrate measuring instruments carefully.

Exercise 48. Translate the following sentences into English.

1. Метрологія – це наука про вимірювання та шляхи досягнення необхідної точності. 2. Одна з головних проблем метрології – створення загальної теорії вимірювань та системи одиниць. 3. В основу старої метричної системи було покладено одиницю довжини – метр і одиницю ваги – грам. 4. Англійці й досі користуються у побуті такими одиницями, як фут, дюйм і фунт.

5. Вимірювальні прилади застосовуються для встановлення співвідношення між величиною і одиницею вимірювання. 6. Ам-

метр служить для вимірювання певних властивостей струму.

7. Міжнародна система одиниць (SI) була прийнята на міжнародній конференції у 1960 році. 8. В основу міжнародної системи одиниць фізичних величин покладено 7 основних одиниць вимірювання: метр, кілограм, cекунда, ампер, кельвін, кандела та моль. 9. Для вимірювання термодинамічної температури застосовується одиниця вимірювання кельвін, сили світла – кандела, а кількості речовини – моль. 10. При розрахунках, якщо всі величини виражені в одиницях SI, не потрібно вводити перехідні коефіцієнти.

Exercise 49. Answer the following questions.

1. What does metrology study? 2. What are the base units of the SI? 3. What units are derived? 4. Why was the SI introduced? 5. What are the Imperial units? Where are they still used?

Exercise 50. Read, practice and learn the following words and word combinations.

Measuring device – вимірювальний пристрій

watt – ват

electrostatic charge – електростатичний заряд

dissipate – розсіювати, розтрачувати

in honour (of) – на честь

invent – винаходити, створювати

voltaic pile – вольтов стовп

familiar – схожий; подібний

forerunner – попередник

steady – постійний; стійкий

dissimilar – несхожий, відмінний

zinc – цинк

silver – срібло

approve – затверджувати

electromotive force (EMF) – електрорушійна сила

nominal voltage – номінальна напруга

single-cell – одноелементний

rechargeable – перезаряджувальний

alkaline battery – лужна акумуляторна батарея

mains – електрична мережа, магістраль

lightning – блискавка

flight of stairs – марш сходів

incandescent light bulb – лампа розжарення

contribution – внесок

advancement – успіх, прогрес

steam engine – паровий двигун

adopt – приймати, затверджувати

instrument – прилад

strength – сила; міцність; опір

comparatively – порівняльно, відносно

multimeter – універсальний вимірювальний прилад

ammeter – амперметр

voltmeter – вольтметр

wattmeter – ваттметр

absorption – абсорбція, поглинання

graduate – градуювати

low resistance coil – котушка низького опору

avoid – уникати

appreciable – значний, помітний

transistor-transistor logic (TTL)–транзистор-транзисторна логіка

consume – витрачати; споживати

Exercise 51. Read, translate text 5 and make a plan of key ideas.