Metric system

Regions that do not use the metric system are marked in red

Metric system - common name international decimal system of units based on the use of the meter and the gram. For two recent centuries existed various options metric system, differing in the choice of base units. Currently, the SI system is internationally recognized. With some differences in details, the elements of the system are the same all over the world. Metric units are widely used around the world in both scientific purposes as well as in everyday life.

The main difference between the metric system and the previously used traditional systems is to use an ordered set of units of measure. For any physical quantity, there is only one main unit and a set of submultiples and multiples, formed in a standard way using decimal prefixes. This eliminates the inconvenience of using a large number of different units(such as inches, feet, fadens, miles, etc.) with complicated rules transformations between them. In the metric system, the conversion is reduced to multiplying or dividing by a power of a number, that is, to a simple permutation of the comma in a decimal fraction.

Attempts were made to introduce metric units for measuring time (by dividing the day, for example, by millidays) and angles (by dividing the revolution by 1000 milliturns or by 400 degrees), but they were not successful. Currently, the SI system uses seconds (divided by milliseconds, etc.) and radians.

Story

The metric system grew out of the decrees adopted by the National Assembly of France in and by definition of the meter as one ten millionth of the section of the earth's meridian from the North Pole to the equator.

19th century

By defining the meter as a ten-millionth part of a quarter of the earth's meridian, the creators of the metric system sought to achieve the invariance and exact reproducibility of the system. They took the gram as a unit of mass, defining it as the mass of one millionth of a cubic meter of water at its maximum density. To facilitate the use of new units in everyday practice, metal standards were created that reproduce these ideal definitions with the utmost accuracy.

It soon became clear that metal standards of length could be compared with each other, introducing a much smaller error than when comparing any such standard with a quarter of the earth's meridian. In addition, it became clear that the accuracy of comparing metal mass standards with each other is much higher than the accuracy of comparing any such standard with the mass of the corresponding volume of water.

In this regard, the International Commission on the Meter decided to take the “archival” meter stored in Paris “as it is” as the standard of length. Similarly, the members of the Commission took the archival platinum-iridium kilogram as the standard of mass, “considering that the simple ratio established by the creators of the metric system between a unit of weight and a unit of volume represents the existing kilogram with an accuracy sufficient to common applications in industry and commerce, and exact sciences need more than just numerical ratio of this kind, but in the most perfect definition of this ratio.

New international organization immediately took up the development of international standards of length and mass and the transfer of their copies to all participating countries.

20th century

The metric system of measures was allowed for use in Russia (optionally) by the law of June 4, the draft of which was developed by D. I. Mendeleev, and introduced as a mandatory decree of the Provisional Government of April 30, and for the USSR - by a decree of the Council of People's Commissars of the USSR of 21 July .

Based on the metric system, the International System of Units (SI) was developed and adopted in 1960 by the XI General Conference on Weights and Measures. During the second half of the 20th century, most countries in the world switched to the SI system.

End of XX century - XXI century

In the 90s of the twentieth century, the widespread use of computer and household appliances from Asia, in which there were no instructions and inscriptions in Russian and other languages ​​of the former socialist countries, but were available in English, led to the displacement of the metric system in a number of areas of technology. So, the sizes of CDs, floppy disks, hard drives, diagonals of monitors and TVs, matrices of digital cameras in Russia are usually indicated in inches.

To date, the metric system has been officially adopted in all countries of the world, except for the USA, Liberia and Myanmar (Burma). last country Ireland (2005) has already completed the transition to the metric system. In the UK and Saint Lucia, the transition to the SI has not yet been completed. In Antigua and Guyana, in fact, this transition is far from over. China, which has completed this transition, nevertheless uses ancient Chinese names for metric units. In the USA for use in science and manufacturing scientific instruments the SI system is adopted, for all other areas - the American version british system units.

Metric variants of traditional units

There were also attempts to slightly change the traditional units so that the ratio between them and metric units became simpler; this also made it possible to get rid of the ambiguous definition of many traditional units. For example:

• metric ton (exactly 1000 kg)
• metric carat (exactly 0.2 g)
• metric pound (exactly 500 g)
• metric foot (exactly 300 mm)
• metric inch (exactly 25 mm)
• metric horsepower (exactly 75 kgf m/s)

Some of these units have taken root; at present, in Russia, "ton", "carat" and "horsepower" without specification always denote the metric versions of these units.

see also

• Traditional measurement systems

Links

• A Brief History of the SI
• imperial and metric automatic conversions
• NASA completely switches to the metric system (Russian) Compulenta -

Wikimedia Foundation. 2010 .

• Metric second
• Metric system of measures and weights

See what the "Metric system" is in other dictionaries:

metric system- a system of weights and measures, widely used in various countries and therefore called international. The metric system was first introduced in France in 1793. In Russia, until 1918, the metric system was allowed to be used ... ... Reference commercial dictionary

METRIC SYSTEM- METRIC, a decimal system of UNITS OF MEASURES and WEIGHTS, based on the unit of length METER (m) and the unit of mass KILOGRAM (kg). Larger and smaller units are calculated by multiplying or dividing by powers of 10. The metric system was... Scientific and technical encyclopedic Dictionary

METRIC SYSTEM- (metric system) A system of measurement based on the decimal system. She first received recognition in France in late XVIII in. and by the 1830s. widely spread in Europe. In the UK, bills for its mandatory introduction are not ... ... Glossary of business terms

metric system- - [A.S. Goldberg. English Russian Energy Dictionary. 2006] Topics energy in general EN metric systemMS ... Technical Translator's Handbook

metric system- metrinė sistema statusas T sritis fizika atitikmenys: angl. metric system; metrical system vok. metrisches System, n rus. metric system, f pranc. système metrique, m … Fizikos terminų žodynas

METRIC SYSTEM- METRIC SYSTEMThe decimal system of weights and measures that originated in France. Basic unit of this system is a meter, approximately equal to one ten-millionth of the distance along the meridian from the equator to the pole, or approx. 39.37 inches Deals on… … Encyclopedia of Banking and Finance

METRIC SYSTEM- applied to the measurement of length sound waves, see Foot tone... Riemann's musical dictionary

METRIC- (decimal system of measures) system of units physical quantities, which is based on the unit of length meter. Multiples and submultiple units metric system of measures are in decimal ratios. Based on the metric system of measures created ... ... Big Encyclopedic Dictionary

Metric, a decimal system of measures, a set of units of physical quantities, which is based on a unit of length - meter. Initially, the Metric system of measures, in addition to the meter, included units: areas - square meter, volume - cubic meter and mass - kilogram (mass of 1 dm 3 of water at 4 ° C), as well as liter(for capacity), ar(for area land plots) and ton(1000 kg). important distinctive feature The metric system of measures was the method of education multiple units and submultiple units, which are in decimal ratios; prefixes were adopted to form the names of derived units: kilo, hecto, soundboard, deci, centi and Milli.

The metric system of measures was developed in France during the French Revolution. At the suggestion of a commission of the largest French scientists (J. Borda, J. Condorcet, P. Laplace, G. Monge, etc.), a unit of length - a meter - was taken as a ten millionth part of 1/4 of the length of the Parisian geographic meridian. This decision was due to the desire to base the metric system of measures on an easily reproducible "natural" unit of length, associated with some practically unchanged object of nature. The decree introducing the metric system of measures in France was adopted on April 7, 1795. In 1799, a platinum prototype of the meter was made and approved. Dimensions, names and definitions of other units of the Metric system of measures have been chosen so that it does not wear national character and could be accepted by all countries. The metric system of measures acquired a truly international character in 1875, when 17 countries, including Russia, signed Metric convention to ensure international unity and improve the metric system. The metric system of measures was approved for use in Russia (optionally) by the law of June 4, 1899, the draft of which was developed by D. I. Mendeleev, and introduced as a mandatory decree of the Council of People's Commissars of the RSFSR of September 14, 1918, and for the USSR - by a decree Council of People's Commissars of the USSR of July 21, 1925.

Based on the metric system of measures arose whole line private, covering only certain sections of physics or branches of technology, systems of units and individual off-system units. The development of science and technology, as well as international relations led to the creation on the basis of the metric system of measures of a single system of units covering all areas of measurement - international system units(SI), which is already accepted as mandatory or preferred by many countries.

got its name from the underlying linear unit called the meter, which was allowed to be introduced in France from December 22, 1795 (1 nivoz of the 4th year of the republic) [The decree on the adoption of the meter as the main measure was issued on 13 Thermidor of the 1st year of the republic July 1793)]. The meter was legalized to be one ten-millionth of a quarter of a meridian; degree measurements were made by the old French measure, toise, in 6 pairs. feet (pied de rois) of 12 inches, in 12 lines or in 864 pairs. lines. The meter, by calculation, turned out to be equal to 443.295936 pairs. lines. The normal standard of the meter at 0 ° is accepted = 443.296 pairs. lines. The subdivisions of the meter are decimal: decimeter (1/10 meter), centimeter (1/100 meter), millimeter (1/1000 meter). In a similar way accepted decameter (10 m), hectometer (100 m), kilometer (1000 m) and myriameter (10000 m); the names decameter and hectometer are almost uncommon. Surface measures, ground: ar = 100 sq. m, hectare = 100 aram = 10,000 sq. m; the names kiloar (1000 ar), myriar (10000 ar) are of little use. Measures of volume for liquids and grains: the main one is a liter (cubic decimeter) \u003d 1 / 1000 cubic meters. m; decalitre (10 liters), hectoliter (100 liters), kiloliter (1000 liters), myrialiter (10000 liters); the last two names are rarely used, and numbers are spoken and written instead. The subdivisions of a liter do not have special names, and the count is kept by the number of cubes. stm. A measure of volume for firewood, sand, etc. is a cube. meter is called ster; decaster (10 stm), hectoster (1000 stm) and large measures are almost never used, and the account is kept simply in numbers. Measures of weight: grams - weight cube. stm of water at its highest density (at 4 ° centigrade thermometer); decigram (1/10 gram), centigram (1/100 gram), milligram (1/1000 gram). Weight values ​​greater than one gram are always indicated by numbers, although the names of decagrams for 10 grams and hectograms for 100 grams could be used according to the system. A weight of 1000 grams is called a kilogram or a kilo. Big weight 100 kilos is called a quintal (metric centner), 1000 kilos - a ton. The latter, to distinguish it from other tons, is called metric (millier metric, tonneau de mer).

M. system, in its harmony and simplicity of relations between measures corresponding to the generally accepted decimal number system, came into use, in addition to France, in many more states, namely in Belgium, Holland, Italy, Austria (since January 1, 1876), Germany (law August 17, 1868 and January 1, 1872), Denmark, Sweden, Switzerland, Spain, Portugal, Turkey, Egypt (since 1875), Mexico (since 1884) - at customs. However, in many of these states, some local measures have not fallen into disuse. In Russia, only Finland introduced the M. system since 1895. England and the United States North America refuse to introduce the M. system, although in England some industrial and commercial people consider it useful to introduce it. Opinions are even expressed that the M. system is not the best possible and that the introduction of the M. system should be treated with great caution. For an assessment of these objections and, in general, the M. system in practical and scientific terms, see Measures and Weight.

F. Petrushevsky.

• - international convention signed in 1875 in Paris by 17 States for the provision of international...
• - system of physical units. quantities, which is based on the unit of length meter. Multiple and submultiple units of M. s. m. are in decimal ratios. Based on M. s. m. created by the International ...

  Natural science. encyclopedic Dictionary

• - the decimal system of UNITS OF MEASURES and WEIGHTS, based on the unit of length METER and the unit of mass KILOGRAM...
• is a system of units based on units such as the centimeter, gram, and second. In this system, the dyne is the unit of force, the erg is the unit of energy...

  Scientific and technical encyclopedic dictionary

• - the English system of measures of weight and all goods, except noble metals, precious stones and drugs...

  Large economic dictionary

• - the main system of weights that is used to determine the weight of precious metals and stones: 1 troy pound = 12 troy ounces = 240 pennyweights = 5760 grains ...

  Big Economic Dictionary

• - a system of measures and weights, which has become widespread in various countries and is therefore called international ...

  Reference commercial dictionary

• Political science. Vocabulary.

• - system of measures, osn. in two units: the meter, a unit of length, and the kilogram, a unit of mass. M. s. m. arose in France in con. 19th century, during the period of the Great French. revolution...

  Big encyclopedic polytechnic dictionary

• - the system of measures currently adopted in most countries, which is based on the meter, kilogram and second ...

  Marine vocabulary

• - A measurement system based on the decimal system. It first gained recognition in France at the end of the 18th century. and by the 1830s. widespread in Europe...

  Glossary of business terms

• - an international convention signed in 1875 in Paris by 17 states, including Russia, to ensure international uniformity of measurements and improve the metric system of measures ...
• - decimal system of measures, a set of units of physical quantities, which is based on a unit of length - Meter. Initially in M. page. m., except for the meter, included units: area - square meter, volume ...

  Great Soviet Encyclopedia

• - an international convention signed in 1875 in Paris by 17 states to ensure international uniformity of measurements and improve the metric system of measures. In 1918 it was recognized as valid for the RSFSR, in 1925 - for ...
• - METRIC MEASURE system - a system of units of physical quantities, which is based on the unit of length meter. Multiple and submultiple units of the metric system of measures are in decimal ratios ...

  Big encyclopedic dictionary

• - 1) a record of birth, marriage and death, which is constantly maintained, moreover, at each parish church; 2) the collection of acts on noble families existing under the Senate ...

  Vocabulary foreign words Russian language

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Metric system French commission of weights and measures in times French Revolution spoke about new system: "The determination of these measures and weights, taken from nature and thereby freed from all arbitrariness, will now be stable, unshakable and

Measuring the mass of goods, their length, volume is a very laborious process that is repeated many times and is calculated daily by many millions of operations. This is especially the case in the food trade, where most pre-sale and post-sale operations involve mandatory weighing. Some household goods are also weighed, Construction Materials. Measure goods in natural indicators when dosing and packing them, when performing most of the operations for receiving and dispensing in warehouses.

History of development

The intensive development of industry and science, as well as the expansion trade relations between different states in the 19th century. were the main reasons that stimulated the emergence and progress of metrology as a science and the formulation as its main problem of creating a unified international system of units that would cover all areas of measurement.

The initial steps in solving this problem were the establishment and international distribution Metric system of measures and weights, development scientific foundations building systems of interconnected units of physical quantities characterizing wide circle phenomena of nature, the creation and practical implementation of the systems of the SGS, MKGSS, MTS, ISS, etc. Many of these systems of units had a limited scope and were not interconnected with each other. Simultaneously with the creation of systems of units, as a result of the desire to provide maximum convenience for measuring and recording the values ​​of certain physical quantities, a number of branches of science and technology appeared in a number of branches of science and technology. a large number of various off-system units. Because of this, there was such a situation that a large number of different units were used for the same quantity (for example, more than 10 units were used for force, more than 30 units for energy and work, 18 units for pressure, etc.).

Development and implementation

The development and implementation of the Metric System of Measures is the first step to eliminate the plurality of units of physical quantities and measures that reproduce them, which hindered the development of industry and trade.

During the French period bourgeois revolution at the insistence of commercial and industrial circles, the National Assembly of France on March 31, 1791 adopted the prepared Special Commission, which included famous French the scholars of that time (Laplace, Lagrange, Borda, Condorcet, Monge, etc.), a proposal to introduce a meter equal to one ten-millionth of a quarter of the earth's meridian as a unit of length. This unit of length was finally approved on December 10, 1799, becoming the basis of the metric system. A platinum rod was chosen as its prototype (initial standard). The second unit of the Metric system was the unit of mass - the kilogram, which was originally equal to the mass in vacuum of a cubic decimeter of water at its highest density(4 °C) in a place at sea level and at a latitude of 45°. The prototype of this unit was the platinum weight. The prototypes of the meter and kilogram are stored in National Archives France and are called "Archive meter" and "Archive kilogram" respectively.

An important advantage of the Metric system of measures was its decimality, since submultiple and multiple units, according to accepted rules, were formed in accordance with the decimal count using decimal factors, which correspond to the prefixes deci, centi, milli, deca, hecto and kilo.

International Diplomatic Conference of Seventeen States (Russia, France, England, USA, Germany, Italy, etc.) on May 20, 1875 adopted the Metric Convention, in which the Metric system of measures was recognized as international, the prototypes of the meter and kilogram were approved. The conference established the International Bureau of Weights and Measures, whose main task was to ensure the uniformity of measurements on an international scale, and formed the International Committee of Weights and Measures, which carried out the scientific management of this work, prepared and held the General Conferences on Weights and Measures (CGPM). The first of these took place in 1889.

Metric law

As a result of great efforts made by the Chief Custodian of the Chamber of Measures and Weights, the great Russian scientist D. I. Mendeleev, an ardent supporter Metric, in Russia on July 4, 1899, a law was adopted, according to which, from January 1900, the Metric system was allowed to be applied "along with the main Russian measures." But only in September 1918, the metric system of measures was officially introduced in Russia. The full transition to the metric system was completed by January 1, 1927.

After completion in 1934, a large and important work to develop and approve standards for units of physical quantities for all areas of science and technology, the task was to improve them and eliminate the significant shortcomings that were inherent in these standards. Main disadvantage was that the standards for various areas applications were based on different systems units.

AT post-war period the main efforts were directed to the development of standards built on the basis of unified system units. From 1955 to 1958 Standards, Measures and measuring instruments approved new GOSTs for units for all areas of measurement. The establishment of new standards took place during the development of the International System of Units, which is modern form The metric system, which is based on the ISS system. Therefore, the new standards basically proceeded from this system. As in the SI, the standards make a clear distinction between the unit of mass (kilogram) and the unit of force (newton), the absence of which had previously often caused confusion between the unit of force in the MKGSS system and the unit of mass in the ISS system.

Measures English-speaking and other countries

In addition to such measures as a yard, a foot, a stock, an inch, the British also use peculiar monetary systems: pounds sterling, shillings and pence. From similar monetary systems abandoned by all the states of the world, but units of physical quantities are still used in English speaking countries. English measures of length are presented as: 1 yard = 3 feet; 1 foot = 12 inches; 1 mile = 5280 feet = 1760 yards.

The units of volume are 1 gallon = 4 quarts = 231 cubic inches, and the units of weight are 1 pound = 16 ounces; 1 firebox = 200 pounds. The British and Americans, using these measures, long ago came to the conclusion that their system was inconvenient and began to introduce the decimal system.

Peter I was the first who tried to link the Russian and English system measures. By his decree, arshin was balanced with 28 English inches, so that a sazhen corresponds to seven English feet. The Russian sazhen to its English feet was equal to 216 cm, and then equaled to 213.36 cm, this is evidenced by the true ruler of Tsar Peter I. leave forever fathoms in seven real English feet, divided into three arshins, each 28 inches or 16 inches.

The pound and inch, which were used in Russia, exactly coincide with the English measures, and in fact the original Russian measures were used in parallel. Thus, systems of measures not expressed in whole numbers were used. So, for example: 1 foot = 66/7 inches, and one inches = 13/4 inches. It was certainly inconvenient. The inconveniences persisted during the transition of our country to the metric system of measures. In English-speaking countries, the metric system of measures was officially recognized in 1879, but the full transition has not been completed even now, national measures do not give up, such is the force of habit in people and the passivity of the governments of these countries.

Old Russian measures

Having recognized the expediency of the transition to the decimal metric system, we still use the measures of our ancestors. Even in state reports, our crops are estimated in billions of poods.

A group of scientists from the United States of America and Europe, by counting atoms in two spheres of silicon weighing one kilogram each, received a new estimate of the Avogadro constant.

Recall that the Avogadro constant N A - determines the number of particles contained in one mole of a given substance. And is link between micro and macrophysics.

The calculation of the Avogadro constant allows us to estimate the value of Planck's constant h, since molar "version" of the latter, equal to N A · h and is calculated based on measurements of the Rydberg constant.

This will make it possible to obtain a new kilogram standard, replacing the obsolete platinum-iridium one made in 1889 and stored in Sèvres near Paris. Calculated what years, since its inception, it has become 50 micrograms lighter.

For the calculations, the formula was used:

Where n = 8 is the number of atoms in elementary cell gratings, M - molar mass, ρ - density, a 3 - unit cell volume.

The central task was to determine the isotopic composition of silicon, and a crystal preliminarily enriched with 28Si was used in the experiments. At the beginning of the experiment, in 2004, SiF4 was enriched in the Central Design Bureau of Mechanical Engineering, then it was converted into SiH4. Next, a polycrystal was grown from the vapor phase by chemical deposition. In 2007, the process of growing a single crystal weighing 5 kg was completed in Germany.

From the obtained sample, two silicon spheres were made, which made it possible to replace the calculation of the volume with the determination of the diameter. After calculating all the quantities, the Avogadro constant was calculated 6.02114893(21) · 1023 and 6.02114775(22) · 1123 mol -1 .

Final averaging gave N A=6.01214184(18) · 1023 mol -1 at relative error 3,0· 10 -8 .

According to the representative of the International Bureau of Weights and Measures, the redefinition of the kilogram will be possible only after the error becomes less than 2.0 · 10 -8 .

http://ucheba-legko.ru/lections/viewlection/fizika/noviu_etalon_kilogramma