In 1795, the Law on New Measures and Weights was passed in France, which established single unit length - meter, equal to ten millionths of a quarter of the arc of the meridian passing through Paris. Hence the name of the system - metric.

A platinum rod one meter long and of a very strange shape was chosen as the standard of the meter. Now the size of all rulers, one meter long, had to correspond to this standard.

Units installed:

- liter as a measure of the capacity of liquid and granular bodies, equal to 1000 cubic meters. centimeters and containing 1 kg of water (at 4 ° heat Celsius),

- gram as a unit of weight (the weight of pure water at a temperature of 4 degrees Celsius in the volume of a cube with an edge of 0.01 m),

- ar as a unit of area (the area of ​​a square with a side of 10 m),

- second as a unit of time (1/86400 of a mean solar day).

Later, the basic unit of mass became kilogram. The prototype of this unit was a platinum weight, which was placed under glass flasks and the air was pumped out - so that dust would not get in and the weight would not increase!

The prototypes of the meter and kilogram are still kept in the National Archives of France and are called "Meter Archive" and "Kilogram Archive" respectively.

There were different measures before, but an important advantage of the Metric system of measures was its decimality, since submultiple and multiple units, according to the 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-.

Currently, the metric system of measures is adopted in Russia and in most countries of the world. But there are other systems as well. For example, English system measures, in which the foot, pound and second are taken as the basic units.

It is interesting that in all countries there are familiar packaging for different foods and drinks. In Russia, for example, milk and juices are usually packaged in liter bags. And large glass jars - entirely three-liter!

Remember: on professional drawings, the dimensions (dimensions) of products are signed in millimeters. Even if these are very large products, like cars!

Volkswagen Cady.

Citroen Berlingo.

Ferrari 360.

On the facade of the Ministry of Justice in Paris, under one of the windows, a horizontal line and the inscription "meter" are carved in marble. Such a miniature detail is barely noticeable against the backdrop of the majestic building of the Ministry and Place Vendôme, but this line is the only “meter standard” remaining in the city, which were located throughout the city more than 200 years ago in an attempt to introduce to the people a new universal system of measurements - metric.

We often take the system of measures for granted and do not even think about the history behind its creation. Metric system, which was invented in France, is official all over the world, with the exception of three countries: the United States, Liberia and Myanmar, although in these countries it is also used in some areas such as international trade.

Can you imagine what our world would be like if the system of measures was different everywhere, like the situation we are used to with currencies? But everything was like that before the French Revolution, which flared up at the end of the 18th century: then the units of measures and weights were different not only between individual states, but even within the same country. Almost every French province had its own units of measures and weights, incomparable with the units used by their neighbors.

The revolution brought a wind of change in this area: in the period from 1789 to 1799, activists sought to overturn not only the government regime, but also fundamentally change society, changing traditional foundations and habits. For example, in order to limit the influence of the church on public life, the revolutionaries introduced a new Republican calendar in 1793: it consisted of ten-hour days, one hour equaled 100 minutes, one minute equaled 100 seconds. This calendar was fully in line with the desire of the new government to introduce the decimal system in France. This approach to calculating time never caught on, but people came to like the decimal system of measures, which was based on meters and kilograms.

The first scientific minds of the Republic worked on the development of a new system of measures. The scientists intended to invent a system that would obey logic, and not local traditions or the wishes of the authorities. Then they decided to be based on what nature gave us - the reference meter had to be equal to one ten millionth of the distance from North Pole to the equator. This distance was measured along the Paris meridian, which passed through the building of the Paris Observatory and divided it into two equal parts.

In 1792, the scientists Jean-Baptiste Joseph Delambre and Pierre Mechain went along the meridian: the first was the city of Dunkirk in northern France, the second followed south to Barcelona. Using the latest equipment and the mathematical process of triangulation (a method of constructing a geodetic network in the form of triangles in which their angles and some of their sides are measured), they calculated to measure the meridian arc between two cities that were at sea level. Then, using the extrapolation method (method scientific research, consisting in extending the conclusions obtained from observation of one part of the phenomenon to another part of it), they were going to calculate the distance between the pole and the equator. According to the initial idea, the scientists planned to spend a year on all measurements and the creation of a new universal system of measures, but in the end the process dragged on for seven whole years.

Astronomers were faced with the fact that in those turbulent times, people often perceived them with great caution and even hostility. In addition, without the support of the local population, scientists were often not allowed to work; there were times when they were injured while climbing highest points in the district like the domes of churches.

From the top of the dome of the Pantheon, Delambre took measurements in Paris. Initially, King Louis XV erected the building of the Pantheon for the church, but the Republicans equipped it as the central geodetic station of the city. Today, the Pantheon serves as a mausoleum for the heroes of the Revolution: Voltaire, Rene Descartes, Victor Hugo, and others. In those days, the building also served as a museum - all the old standards of measures and weights that were sent by the inhabitants of France in anticipation of a new perfect system were stored there.

Unfortunately, despite all the efforts of scientists to develop a worthy replacement for the old units of measurement, no one wanted to use the new system. People refused to forget the usual ways of measuring, which were often closely connected with local traditions, rituals and way of life. For example, ale - a unit of measure for cloth - was usually equal to the size of looms, and the size of arable land was calculated solely in days that needed to be spent on it.

The Parisian authorities were so outraged by the refusal of the inhabitants to use the new system of measures that they often sent police to local markets to force them into circulation. As a result, in 1812 Napoleon abandoned the policy of introducing the metric system - it was still taught in schools, but people were allowed to use the usual units of measure until 1840, when the policy was resumed.

It took almost a hundred years for France to completely switch to the metric system. This finally succeeded, but not thanks to the persistence of the government: France was moving rapidly in the direction of the industrial revolution. In addition, it was necessary to improve maps of the area for military purposes - this process required accuracy, which was not possible without a universal system of measures. France confidently entered the international market: in 1851, the first International Fair took place in Paris, where the participants of the event shared their achievements in the field of science and industry. The metric system was simply necessary to avoid confusion. erection eiffel tower 324 meters high was dedicated to the International Fair in Paris in 1889 - then it became the tallest man-made structure in the world.

In 1875, the International Bureau of Weights and Measures was established, headquartered in a quiet suburb of Paris - in the city of Sèvres. The Bureau maintains international standards and the unity of seven measures: meter, kilogram, second, ampere, Kelvin, Mole and Candela. A platinum standard meter is stored there, from which standard copies were carefully made and sent to other countries as a sample. In 1960, the General Conference of Weights and Measures adopted a definition of the meter based on the wavelength of light - thus making the standard even closer to nature.

At the headquarters of the Bureau there is also a kilogram standard: it is located in an underground storage under three glass caps. The standard is made in the form of a cylinder of an alloy of platinum and iridium, in November 2018 the standard will be revised and redefined using Planck's quantum constant. The resolution on the revision of the International System of Units was adopted back in 2011, however, due to some technical features of the procedure, its implementation was not possible until recently.

Determining the units of measures and weights is a very time-consuming process, which is accompanied by various difficulties: from the nuances of conducting experiments to financing. The metric system underlies progress in many fields: science, economics, medicine, etc., it is vital for further research, globalization and improvement of our understanding of the universe.

Universal measure

The original proposal was expressed at the time by Professor of the University of Krakow S. Pudlovsky. His idea was that as a single measure one should take the length of the pendulum, which makes a full swing in one second. This proposal was published in the book "Universal Measure", published in Vilna in 1675 by his student T. Buratini. He also proposed to name meter unit of length.

Somewhat earlier, in 1673, the Dutch scientist H. Huygens published the brilliant work "Pendulum Clock", where he developed the theory of oscillations and described the construction of pendulum clocks. Based on this work, Huygens proposed his own universal measure of length, which he called hourly foot, and in size the hourly foot was equal to 1/3 of the length of the second pendulum. “This measure can not only be determined everywhere in the world, but can always be restored for all future ages,” Huygens wrote proudly.

However, there was one circumstance that confused scientists. The period of oscillation of a pendulum with the same length was different depending on the geographical latitude, that is, the measure, strictly speaking, was not universal.

Huygens' idea was propagated by the French geodesist Ch. Condamine, who proposed to base the measurement system on a unit of length corresponding to the length of a pendulum making one swing per second at the equator.

The French astronomer and mathematician G. Mouton also supported the idea of ​​a second pendulum, but only as a control apparatus, and G. Mouton proposed to put the principle of connection of a unit of measurement with the dimensions of the Earth as a basis for the universal system of measures, i.e., take a part as a unit of length meridian arc length. This scientist also proposed to divide the measured part into tenths, hundredths and thousandths, that is, to use the decimal principle.

Metric

Measures reform projects appeared in different countries, but this issue was especially acute in France for the reasons listed above. Gradually, the idea of ​​creating a system of measures that meets certain requirements emerged:

- the system of measures should be unified and common;

- units of measurement must have strictly defined dimensions;

- there must be standards of units of measurement, unchanged in time;

- for each quantity there should be only one unit;

– units of different quantities should be related to each other in a convenient way;

– units must have submultiple and multiple values.

On May 8, 1790, the National Assembly of France adopted a decree on the reform of the system of measures and instructed the Paris Academy of Sciences to carry out the necessary work, guided by the above requirements.

Several commissions have been formed. One of them, led by academician Lagrange, recommended the decimal subdivision of multiples and submultiples of units.

Another commission, which included scientists Laplace, Monge, Borda and Condors, proposed to accept one forty-millionth part of the earth's meridian as a unit of length, although the overwhelming majority of experts who knew the essence of the matter thought that the choice would be in favor of a second pendulum.

The decisive factor here was that a stable basis was chosen - the size of the Earth, the correctness and invariance of its shape in the form of a ball.

Commission member Ch. Borda, a geodesist and hydraulician, proposed calling the unit of length a meter; in 1792, he determined the length of a second pendulum in Paris.

On March 26, 1791, the National Assembly of France approved the proposal of the Paris Academy, and a temporary commission was formed for the practical implementation of the decree on the reform of measures.

On April 7, 1795, the National Convention of France passed a law on new weights and measures. It was accepted that meter- one ten-millionth part of a quarter of the earth's meridian passing through Paris. but at the same time, it was especially emphasized that the introduced unit of length in name and size did not coincide with any of the French units of length that existed at that time. Therefore, the possible further argument that France is “pushing through” its system of measures as an international one is ruled out.

Instead of temporary commissions, commissioners were appointed, who were instructed to carry out work on the experimental determination of units of length and mass. The famous scientists Berthollet, Borda, Brisson, Coulomb, Delambre, Gaui, Lagrange, Laplace, Méchain, Monge and others were among the commissioners.

Delambre and Méchain resumed work on measuring the length of the meridian arc between Dunkirk and Barcelona, ​​corresponding to the 9° 40′ sphere (later this arc was extended from the Shetland Islands to Algeria).

These works were completed by the autumn of 1798. Standards of the meter and kilogram were made of platinum. The standard meter was a platinum bar 1 meter long and 25 × 4 mm in section, i.e. it was end measure, and on June 22, 1799, the prototypes of the meter and kilogram were solemnly transferred to the Archives of France, and since then they have been called archival. But it must be said that even in France the metric system was not established immediately, traditions and inertia of thinking had a great effect. Napoleon, who became emperor of France, did not like the metric system, to put it mildly. He believed: “There is nothing more contrary to the mindset, memory and reason than what these scientists offer. The welfare of present generations has been sacrificed to abstractions and empty hopes, for in order to force the old nation to adopt new units of measures and weights, all administrative rules, all the calculations of industry, must be altered. Such work frightens the mind. In 1812, by decree of Napoleon, the metric system in France was abolished, and only in 1840 was it restored again.

Gradually, the metric system was adopted and introduced by Belgium, Holland, Spain, Portugal, Italy, a number of republics South America. The initiators of the introduction of the metric system in Russia were, of course, scientists, engineers, researchers, but tailors, seamstresses and milliners played a significant role - by that time, Parisian fashion had conquered high society, and there, mainly masters who came from abroad worked with their meters . It was from them that the still existing narrow strips of oilcloth matter - "centimeters", which are still in use, came from.

At the Paris Exhibition of 1867, the International Committee for Measures, Weights and Coins was created, which compiled a report on the benefits of the metric system. However, the report compiled in 1869 by academicians O. V. Struve, G. I. Wild and B. S. Jacobi, sent on behalf of the St. Petersburg Academy of Sciences to the Paris Academy, had a decisive influence on the entire subsequent course of events. The report argued for the need to introduce an international system of weights and measures based on the metric system.

The proposal was supported by the Paris Academy, and the French government turned to all interested states with a request to send scientists to the International Metric Commission to solve practical problems. By that time, it turned out that the shape of the Earth is not a ball, but a three-dimensional spheroid (the average radius of the equator is 6,378,245 meters, the difference between the largest and smallest radii is 213 meters, and the difference between the average radius of the equator and the polar semi-axis is 21,382 meters). In addition, repeated measurements of the arc of the Parisian meridian gave the value of the meter somewhat lower than the value obtained by Delambre and Méchain. In addition, there is always the possibility that with the creation of more advanced measuring instruments and the emergence of new measurement methods, the measurement results will change. Therefore, the commission made an important decision: “The new prototype of the measure of length should be equal in size to the Archival meter,” that is, it should be an artificial standard.

The International Commission also adopted the following decisions.

1) The new prototype of the meter must be a line measure, it must be made of an alloy of platinum (90%) and iridium (10%) and have an X-shaped section.

2) In order to give the metric system an international character and ensure uniformity of measures, standards should be prepared and distributed among the countries concerned.

3) One standard, the closest in value to the Archival one, is accepted as international.

4) Instruct practical work on the creation of standards of the French section of the commission, since the archival prototypes are in Paris.

5) Appoint a permanent international committee of 12 members to direct the work.

6) Establish the International Bureau of Weights and Measures as a neutral scientific institution based in France.

In accordance with the decision of the commission, practical measures were taken and in 1875 a international Conference in Paris, at the last meeting of which, on May 20, 1875, the Meter Convention was signed. It was signed by 17 countries: Austria-Hungary, Argentina, Belgium, Brazil, Venezuela, Germany, Denmark, Spain, Italy, France, Peru, Portugal, Russia, USA, Turkey, Switzerland, Sweden and Norway (as one country). Three more countries (Great Britain, Holland, Greece), although they participated in the conference, did not sign the Convention because of disagreement on the functions of the International Bureau.

For the International Bureau of Weights and Measures, the Bretel Pavilion was assigned, located in the Saint-Cloud Park in the suburbs of Paris - Sevres, and soon a laboratory building with equipment was built near this pavilion. The activities of the Bureau are carried out at the expense of funds transferred by the countries - members of the Convention in proportion to the size of their population. At the expense of these funds, standards of the meter and kilogram (36 and 43, respectively) were ordered in England, which were made in 1889.

Meter standards

The meter standard was a platinum-iridium X-shaped rod 1020 mm long. On the neutral plane at 0 °C, three strokes were applied on each side, the distance between the middle strokes was 1 meter (Fig. 1.1). The standards were numbered and compared with the Archival meter. Prototype No. 6 turned out to be closest to the Archival one, and it was approved as an international prototype. Thus, the standard of the meter became artificial and represented dashed measure.

Four more witness standards were added to Standard No. 6 and they were retained by the International Bureau. The remaining standards were distributed by lot among the countries that signed the Convention. Russia got standards No. 11 and No. 28, and No. 28 was closer to the international prototype, so it became the national standard of Russia.

By decree of the Council of People's Commissars of the RSFSR of September 11, 1918, prototype No. 28 was approved as the state primary standard of the meter. In 1925, the Council of People's Commissars of the USSR adopted a resolution recognizing the Metric Convention of 1875 as valid for the USSR.

In 1957 - 1958 a scale with decimeter divisions was applied to the standard No. 6, the first decimeter was divided into 10 centimeters, and the first centimeter into 10 millimeters. After applying strokes, this standard was re-certified by the International Bureau of Weights and Measures.

The error in the transmission of a unit of length from the standard to the measuring instruments was 0.1 - 0.2 microns, which becomes clearly insufficient with the development of technology, therefore, in order to reduce the transmission error and obtain a natural indestructible standard, a new standard of the meter was created.

Back in 1829, the French physicist J. Babinet proposed to take the length of a certain line in the spectrum as a unit of length. However, the practical implementation of this idea occurred only when the American physicist A. Michelson invented the interferometer. Together with the chemist Morley E. Babinet J. published the work “On the method of using the wavelength of sodium light as a natural and practical standard of length”, then he moved on to the study of isotopes: mercury - green and cadmium - red lines.

In 1927 it was accepted that 1 m equals 1553164.13 wavelengths of the red line of cadmium-114, this value was accepted as a standard along with the old prototype meter.

In the future, work was continued: in the USA, the spectrum of mercury was studied, in the USSR - cadmium, in the Federal Republic of Germany and France - krypton.

In 1960, the XI General Conference on Weights and Measures adopted the meter as a standard unit of length, expressed in wavelengths of light, and specifically, the inert gas Kr-86. Thus, the standard of the meter again became natural.

Meter is a length equal to 1650763.73 wavelengths in vacuum of radiation corresponding to the transition between the levels 2p 10 and 5d 5 of the krypton-86 atom. The old definition of the meter is canceled, but the prototypes of the meter remain and are stored in the same conditions.

In accordance with this decision, the State Primary Standard (GOST 8.020-75) was established in the USSR, which included the following components (Fig. 1.2):

1) source of primary reference radiation of krypton-86;

2) a reference interferometer used to study sources of primary reference radiation;

The accuracy of reproduction and transmission of a meter in light units is 1∙10 -8 m.

In 1983, the XVII General Conference on Weights and Measures adopted a new definition of the meter: 1 meter is a unit of length equal to the path traveled by light in vacuum in 1/299792458 of a second, i.e. the standard of the meter remains natural.

The composition of the standard meter:

1) source of primary reference radiation - a highly frequency-stabilized helium-neon laser;

2) a reference interferometer used to study sources of primary and secondary reference measurements;

3) a reference interferometer used to measure the length of line and end measures (secondary standards).

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Metric system (International SI system)

Metric system of measures (International SI system)

Residents of the United States or another country where the metric system is not used sometimes find it difficult to understand how the rest of the world lives in and navigates it. But in fact, the SI system is much simpler than all traditional national measurement systems.

The principles of constructing the metric system are very simple.

The device of the international system of units SI

The metric system was developed in France in the 18th century. The new system was intended to replace the chaotic set of different units of measurement then in use with a single common standard with simple decimal coefficients.

The standard unit of length was defined as one ten-millionth of the distance from the Earth's north pole to the equator. The resulting value is called meter. The definition of the meter was later refined several times. The modern and most accurate definition of a meter is: "the distance that light travels in a vacuum in 1/299792458 of a second." The standards for the rest of the measurements were set in a similar way.

The metric system or International System of Units (SI) is based on seven basic units for seven basic dimensions independent of each other. These measurements and units are: length (meter), mass (kilogram), time (second), electric current (ampere), thermodynamic temperature (kelvin), amount of substance (mol) and radiation intensity (candela). All other units are derived from base units.

All units of a particular measurement are built on the basis of the base unit by adding universal metric prefixes. The metric prefix table is shown below.

Metric prefixes

Metric prefixes simple and very comfortable. It is not necessary to understand the nature of the unit in order to convert a value from, for example, kilo-units to mega-units. All metric prefixes are powers of 10. The most commonly used prefixes are highlighted in the table.

By the way, on the page Fractions and percentages you can easily convert the value from one metric prefix to another.

Prefix	Symbol	Degree	Factor
yotta	Y	10 24	1,000,000,000,000,000,000,000,000
zetta	Z	10 21	1,000,000,000,000,000,000,000
exa	E	10 18	1,000,000,000,000,000,000
peta	P	10 15	1,000,000,000,000,000
tera	T	10 12	1,000,000,000,000
giga	G	10 9	1,000,000,000
mega	M	10 6	1,000,000
kilo	k	10 3	1,000
hecto	h	10 2	100
soundboard	da	10 1	10
deci	d	10 -1	0.1
centi	c	10 -2	0.01
Milli	m	10 -3	0.001
micro	µ	10 -6	0.000,001
nano	n	10 -9	0.000,000,001
pico	p	10 -12	0,000,000,000,001
femto	f	10 -15	0.000,000,000,000,001
atto	a	10 -18	0.000,000,000,000,000,001
zepto	z	10 -21	0.000,000,000,000,000,000,001
yokto	y	10 -24	0.000,000,000,000,000,000,000,001

Even in countries where the metric system is used, most people only know the most common prefixes, such as "kilo", "milli", "mega". These prefixes are highlighted in the table. The remaining prefixes are used mainly in science.

international decimal system measurement, which is based on the use of units such as kilogram and meter, is called metric. Varied Options metric system developed and used over the past two hundred years, and the differences between them consisted mainly in the choice of basic, basic units. At present, the so-called International system of units (SI). Those elements that are used in it are identical all over the world, although there are differences in some details. International system of units very widely and actively used all over the world, and both in Everyday life as well as in scientific research.

Presently Metric used in most countries of the world. There are, however, several large states in which to this day the English system of measures based on such units as the pound, foot and second is used. These include the UK, US and Canada. However, these countries have also already adopted several legislative measures aimed at moving towards Metric.

She herself originated in the middle of the XVIII century in France. It was then that scientists decided that they should create system of measures, which will be based on units taken from nature. The essence of this approach was that they always remain unchanged, and therefore the whole system as a whole will be stable.

Measures of length

• 1 kilometer (km) = 1000 meters (m)
• 1 meter (m) = 10 decimeters (dm) = 100 centimeters (cm)
• 1 decimeter (dm) = 10 centimeters (cm)
• 1 centimeter (cm) = 10 millimeters (mm)

Measures of area

• 1 sq. kilometer (km 2) \u003d 1,000,000 sq. meters (m 2)
• 1 sq. meter (m 2) \u003d 100 square meters. decimeters (dm 2) = 10,000 sq. centimeters (cm 2)
• 1 hectare (ha) = 100 aram (a) = 10,000 sq. meters (m 2)
• 1 ar (a) \u003d 100 square meters. meters (m 2)

Measures of volume

• 1 cu. meter (m 3) \u003d 1000 cubic meters. decimeters (dm 3) \u003d 1,000,000 cubic meters. centimeters (cm 3)
• 1 cu. decimeter (dm 3) = 1000 cu. centimeters (cm 3)
• 1 liter (l) = 1 cu. decimeter (dm 3)
• 1 hectoliter (hl) = 100 liters (l)

Measures of weight

• 1 ton (t) = 1000 kilograms (kg)
• 1 centner (c) = 100 kilograms (kg)
• 1 kilogram (kg) = 1000 grams (g)
• 1 gram (g) = 1000 milligrams (mg)

Metric

It should be noted that the metric system of measure was not immediately recognized. As for Russia, in our country it was allowed to be used after it signed Metric convention. At the same time, this system of measures for a long time it was used in parallel with the national one, which was based on such units as the pound, sazhen and bucket.

Some old Russian measures

Measures of length

• 1 verst = 500 fathoms = 1500 arshins = 3500 feet = 1066.8 m
• 1 fathom = 3 arshins = 48 vershoks = 7 feet = 84 inches = 2.1336 m
• 1 arshin = 16 inches = 71.12 cm
• 1 inch = 4.450 cm
• 1 foot = 12 inches = 0.3048 m
• 1 inch = 2.540 cm
• 1 nautical mile = 1852.2 m

Measures of weight

• 1 pood = 40 pounds = 16.380 kg
• 1 lb = 0.40951 kg

Main difference Metric from those that were used earlier is that it uses an ordered set of units of measure. This means that any physical quantity characterized by a certain main unit, and all submultiple and multiple units are formed according to common standard, namely, with the use of decimal prefixes.

The introduction of this systems of measures eliminates the inconvenience that was previously caused by the abundance of various units of measurement that have enough complicated rules transformations among themselves. Those in metric system are very simple and boil down to the fact that the original value is multiplied or divided by a power of 10.