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Imperial units- Имперские единицы

Emergence- появление

customary units- обычные единицы

to adopt- принять

remain- остаться

gallon- галлон

despite – несмотря на

imperial fluid ounce- имперская жидкая унция

inch-дюйм, дюймовый, медленно двигаться

Text 2

Systems of measurement

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 system came to be known as U.S. customary units in the United States and is still in use there and in a few Caribbean countries. These various systems of measurement have at times been called foot-pound-second systems after the Imperial units for distance, weight and time. Many Imperial units remain in use in Britain despite the fact that it has officially switched to the SI system. Road signs are still in miles, yards, miles per hour, and so on, people tend to measure their own height in feet and inches and milk is sold in pints, to give just a few examples. Imperial units are used in many other places, for example, in many Commonwealth countries that are considered metricated, land area is measured in acres and floor space in square feet, particularly for commercial transactions (rather than government statistics). Similarly, the imperial gallon is used in many countries that are considered metricated at gas/petrol stations, an example being the United Arab Emirates.

The metric system is a system of measurement used in most of the world. It is also called the International System of Units, or SI.

British imperial Units

Imperial units were defined in the United Kingdom in 1825. Imperial units were used in countries that were part of the British Empire. While many of these countries, including the United Kingdom, have officially adopted SI, the older system of units is still used

US customary units are the official units used in the US. These are similar to the British imperial units and are also based on the units used in the United Kingdom from before American Independence. But some of the units are different to the British ones. For example, there are 20 imperial fluid ounces in an imperial pint, but 16 US fluid ounces in a US pint. Additionally, the US fluid ounce is slightly bigger than the imperial fluid ounce. The result is that US pints and gallons are smaller than imperial pints and gallons. In the United States, the metric system has been legal for trade since 1866 but other measurements such as the gallon, inch, and the pound are still widely used.

SI Units are the most widely used system of units. They are the most common system for everyday commerce in the world, and are almost universally used in the realm of science. The name derives from the French phrase, Système International d'Unités, or in English International System of Units. The system consists of a set of seven base units together with a set of prefixes from which all other units are derived.

The emergence of an internationally recognized system of units at a time of increasing international cooperation and trade is highly significant. It has provided a necessary common base for the scientific, technical, and industrial exchange that has fostered a growing consciousness of the need to approach issues from a global perspective.

The metric system was officially adopted in France after the French Revolution. During the history of the metric system, a number of variations have evolved and their use spread around the world replacing many traditional measurement systems.

By the end of World War II a number of different systems of measurement were still in use throughout the world. Some of these systems were metric system variations while others were based on the Imperial and American systems. It was recognized that additional steps were needed to promote a worldwide measurement system. As a result, the 9th General Conference on Weights and Measures (CGPM) in 1948, asked the International Committee for Weights and Measures (CIPM) to conduct an international study of the measurement needs of the scientific, technical, and educational communities.

Based on the findings of this study, the 10th CGPM in 1954 decided that an international system should be derived from six base units to provide for the measurement of temperature and optical radiation in addition to mechanical and electromagnetic quantities. The six base units recommended were the meter, kilogram, second, ampere, Kelvin (later renamed kelvin), and the candela. In 1960, the 11th CGPM named the system the International System of Units. The seventh base unit, the mole, was added in 1970 by the 14th CGPM.

SI units are still sometimes referred to as the metric system, especially in the United States, whose population has not widely adopted it, and in the United Kingdom, where conversion is only partial. SI units are a specific canon of measurements derived and extended from the Metric system; however, not all metric units of measurement are accepted as SI units. This international system of units is now either obligatory or permissible throughout the world. It is administered by the standards organization: the Bureau International des Poids et Mesures (International Bureau of Weights and Measures, BIPM).

Length

The most important unit is length: one meter was originally defined to be equal to 1/10,000,000^th of the distance from the pole to the equator along the meridian through Paris. (Prior discussions had often suggested the length of a seconds pendulum in some standard gravity, which would have been only slightly shorter, and perhaps easier to determine.) This is approximately 10 percent longer than one yard. Later on, a platinum rod with a rigid, X-shaped cross section was produced to serve as the easy-to-check standard for one meter's length. Due to the difficulty of actually measuring the length of a meridian quadrant in the eighteenth century, the first platinum prototype was short by 0.2 millimeters. More recently, the meter was redefined as a certain multiple of a specific radiation wavelength, and currently it is defined as the distance traveled by light in a vacuum in a specific period of time. Attempts to relate an integer multiple of the meter to any meridian have been abandoned.

Mass

The original base unit of mass in the metric system was the gram, chosen to match the mass of one cubic centimeter of water. For practical reasons, the reference standard that was deposited at the Archives de la république on June 22, 1799, was a kilogram (a cylinder of platinum). One kilogram is about 2.2 pounds. In 1889, the first General Conference on Weights and Measures (CGPM) sanctioned a replacement prototype, a cylinder of a 90 percent platinum, 10 percent iridium alloy; this has served as the standard ever since and is stored in a Paris vault. The kilogram became the base unit in 1901.

Also in 1901, a kilogram of distilled pure water at its densest (+3.98° C) under a standard atmosphere of pressure was used to define the liter, a more convenient unit than the very large cubic meter. Because this liter turned out to be different from the cubic decimeter by about 28 millionths, this definition was abandoned in 1964 in favor of the cubic decimeter.

The kilogram is the only base unit not to have been redefined in terms of an unchanging natural phenomenon. Such a definition, said to be in terms of an artefact (the cylinder in Paris), is particularly inconvenient, because, in principle, it can be used only by traveling to Paris and, with permission, comparing one's own candidate standard to the reference one. For this reason, as well as the effort required to protect the standard from absorption or dispersion of gases and vapors, at a meeting of the Royal Society in London on February 15, 2005, scientists called for the mass of the standard kilogramme in Paris to be replaced by a standard based on "an invariable property of nature"; but no decision on redefinition can be taken before 2007.

Temperature

The metric unit of temperature originally was the centigrade or Celsius scale. This was determined by divided into 100 equal-length parts the difference between a water-ice mixture at 0 °C and the boiling point of pure distilled water at 100 °C (under a standard atmosphere). This is still the metric unit of temperature in everyday use. With the discovery of absolute zero, a new temperature scale, the Kelvin Scale was developed, which relocates the zero point to absolute zero. The freezing point of water, 0 °C, becomes 273.15 K. It is the Kelvin scale that is used as the base SI unit.

Time

The metric unit of time is the second. It was originally defined as 1/86,400^th of a mean solar day. The formal definition of the second has been changed several times as more accurate definitions became possible, based first on astronomic observations, then the tuning fork clock, quartz clock, and today the cesium atomic clock

SI prefixes

The SI system of units is a metric system. That is, the units are expressed in powers of 10 (i.e. 1×10 ³ ). In order to simplify writing the powers of ten, they are expressed as prefixes and the symbol for the prefix put before the unit. Thus, 7.4×10 ³ m is written as 7.4 km.

The following SI prefixes can be used to prefix any of the units to produce a multiple or submultiple of the original unit. This includes the degree Celsius (e.g. "1.2 m°C"); however, to avoid confusion, prefixes are not used with the time-related unit symbols min (minute), h (hour), d (day). They are not recommended for use with the angle-related symbols ° (degree), ' (minute of arc), and " (second of arc), but for astronomical usage, they are sometimes used with seconds of arc.

Task №1

Answer the questions.

1. What units were used in Britain?

2. What is a system of measurement used in most of the world?

3. When were Imperial units defined in the United Kingdom?

4. Is the most important unit length or mass?

5. The metric unit of time is the first, isn’t it?

Task № 2

Put the verb into active or passive form.

1. Before SI units _____widely around the world, the British systems of English units and later Imperial units were used in Britain, the Commonwealth and the United States. (adopt) 2. These various systems of measurement ___at times ____ foot-pound-second systems after the Imperial units for distance, weight and time. (call) 3. Imperial units ___in many other places, for example, in many Commonwealth countries that ____ metricated, land area is measured in acres and floor space in square feet. (use)/ (consider) 4. Imperial units ____ in countries that were part of the British Empire (use).5. The metric system ___ officially in France after the French Revolution. (adopt)

Task №3

Put in a/an or the where necessary.

1. There are 20 imperial fluid ounces in ___imperial pint, but 16 US fluid ounces in ___US pint. 2. Additionally, ___US fluid ounce is slightly bigger than ___ imperial fluid ounce. 3. ___emergence of __internationally recognized system of units at __ time of increasing international cooperation and trade is highly significant. 4. During __history of __metric system, __number of variations have evolved and their use spread around __ world replacing many traditional measurement systems.5. ___International Committee for Weights and Measures (CIPM) to conduct ___international study of the measurement needs of ___ scientific, technical, and educational communities.

Task №4

Put in the missing preposition.

1. The metric system is a system ___ measurement used in most ____ the world.

2. These are similar ___the British imperial units and are also based ___ the units used ___ the United Kingdom __before American Independence. But some ___ the units are different___the British ones. 3. The most important unit is that___ length: one meter was originally defined to be equal ___1/10,000,000^th ___ the distance ___the pole ___ the equator ___ the meridian ___ Paris.4. The name derives __ the French phrase, Système International d'Unités, or __ English International System __ Units. 5. The system consists of a set __seven base units together ___ a set ___ prefixes ___ which all other units are derived.

Task №5

Put the verb into the correct form.

1. The original base unit of mass in the metric system ___ the gram. (to be) 2. In 1889, the first General Conference on Weights and Measures (CGPM) ____a replacement prototype, a cylinder of a 90 percent platinum, 10 percent iridium alloy. (sanction)3. This ___as the standard ever since and is stored in a Paris vault. (serve) 4. The kilogram ____the base unit in 1901.( become) 5. The formal definition of the second ____several times as more accurate definitions ___possible, based first on astronomic observations, then the tuning fork clock, quartz clock, and today the cesium atomic clock. (change/ become)

Task № 6

Complete the sentence. Use the comparative or superlative form.

1. The result is that US pints and gallons are (small) imperial pints and gallons. 2. They are (common) system for everyday commerce in the world.3. The US fluid ounce is slightly (big) the imperial fluid ounce. 4. The result is that US pints and gallons are (small) imperial pints and gallons. 5. Prior discussions had often suggested the length of a seconds pendulum in some standard gravity, which would have been only slightly (short), and perhaps (easy) to determine.) This is approximately 10 percent (long) one yard.

Task № 7

Make questions to the underlined words

1. Imperial units were used in countries that were part of the British Empire.

2. In the United States, the metric system has been legal for trade since 1866 but other measurements such as the gallon, inch, and the pound are still widely used.

3. The original base unit of mass in the metric system was the gram, chosen to match the mass of one cubic centimeter of water.

4. The kilogram is the only base unit not to have been redefined in terms of an unchanging natural phenomenon.

5. The metric unit of time is the second. It was originally defined as 1/86,400^th of a mean solar day.