The international system of units is a structure based on the use of mass indicators in kilograms and lengths in meters. Since its inception, its various options existed. The difference between them was the selection of key indicators. Today, many countries use units of measure in the SI system. In it, the elements are the same for all states (with the exception of the United States, Liberia, Burma). This system is widely used in various fields - from everyday life to scientific research.
Features
The metric system is an ordered set of parameters. This significantly distinguishes it from the previously used traditional methods for determining certain units. To denote any value, the metric system uses only one basic indicator, the value of which can be changed in multiple fractions (achieved by the use of decimal auxiliary elements). The main advantage with this approach is its simpler use. This eliminates a huge number of different unnecessary units (feet, miles, inches, and others).
Time parameters
Over a long period, a number of scientists have attempted to represent time in metric units. It was proposed to divide the day into smaller elements - milliseconds, and angles - by 400 degrees or take the full cycle of revolution for 1000 millio-revolutions. Over time, due to inconvenience in use, I had to abandon this idea. Today, time in SI is indicated by seconds (consist of milliseconds) and radians.
History of occurrence
It is believed that the modern metric system was born in France. In the period from 1791 to 1795 in this country was adopted a number of important legislative acts. They were aimed at determining the status of the meter - one ten-millionth of a quarter of the meridian from the equator to the North Pole. July 4, 1837 adopted a special document. According to him, the mandatory use of the elements that made up the metric system of measures was officially approved in all economic transactions carried out in France. Subsequently, the adopted structure began to spread to neighboring European countries. Due to its simplicity and convenience, the metric system gradually replaced most of the national ones used earlier. It can also be used in the United States and Great Britain.
Core quantities
The founders of the system, as noted above, took a meter for a unit of length. A gram became the element of mass - the weight of one millionth m 3 of water at its standard density. For a more convenient use of units of the new system, the creators came up with a way to make them more affordable - by making metal standards. These models are made with perfect accuracy in reproducing quantities. Where are the metric standards, will be discussed below. Later, when using these models, people realized that comparing the desired value with them is much easier and more convenient than, for example, with a quarter of the meridian. At the same time, determining the mass of the desired body, it became obvious that evaluating it by the standard is much more convenient than by the corresponding amount of water.
Archival Samples
By a resolution of the International Commission in 1872, a specially made meter was adopted as the standard for measuring length. Then the members of the commission decided to take a special kilogram as the standard for measuring mass . It was made from alloys of platinum and iridium. The “archival” meter and kilogram are permanently stored in Paris. In 1885, on May 20th, representatives of seventeen countries signed a special Convention. As part of it, the procedure for determining and using measurement standards in scientific research and works was regulated. For this, special organizations were needed. These include, in particular, the International Bureau of Weights and Measures. Within the framework of the newly created organization, the development of samples of mass and length began, with the subsequent transfer of their copies to all participating countries.
Metric system in Russia
Accepted samples used by more and more countries. Under the current conditions, Russia could not ignore the emergence of a new system. Therefore, the Law of July 4, 1899 (author and developer - D.I. Mendeleev) allowed it to be used optionally. It became mandatory only after the adoption by the Provisional Government of the relevant decree of 1917. Later its application was enshrined in a decree of the Council of People's Commissars of the USSR of July 21, 1925. In the twentieth century, most countries switched to measurements in the international system of units of SI. Its final version was developed and approved by the XI General Conference in 1960.
Post-Soviet time
The collapse of the USSR coincided with the moment of rapid development of computer and household appliances, the main production of which is concentrated in Asian countries. Huge consignments of goods of these manufacturers began to be imported into the territory of the Russian Federation. At the same time, the Asian states did not think about the possible problems and inconvenience of the operation of their goods by the Russian-speaking population and supplied their products with universal (in their opinion) instruction in English, using American parameters. In everyday life, the designation of values ​​according to the metric system began to be replaced by elements used in the USA. For example, the sizes of computer disks, diagonals of monitors and other components are indicated in inches. Moreover, initially the parameters of these components were designated strictly in terms of the metric system (the width of the CD and DVD, for example, is 120 mm).
International use
Currently, the most common on planet Earth is the metric system of measures. A table of masses, lengths, distances and other parameters makes it easy to translate some indicators into others. Countries, for certain reasons that have not switched to this system, are becoming less and less every year. Such states that continue to use their own parameters include the United States, Burma, and Liberia. America uses the SI system in the fields of scientific production. All others used American parameters. Great Britain and Saint Lucia have not yet switched to the global SI system. But I must say that the process is in an active stage. The last of the countries that finally switched to the metric system in 2005 was Ireland. Antigua and Guyana are only making the transition, but the pace is very slow. An interesting situation is in China, which officially switched to the metric system, but at the same time the use of ancient Chinese units continues on its territory.
Aviation Parameters
The metric system of measures is recognized almost universally. But there are certain industries in which it did not take root. In aviation, a measurement system is still used, based on values ​​such as a foot and a mile. The application of this system in this area has developed historically. The position of the International Civil Aviation Organization is unequivocal - a transition to metric values ​​should be made. However, only a few countries adhere to these recommendations in their pure form. Among them are Russia, China and Sweden. Moreover, the civil aviation structure of the Russian Federation, in order to avoid confusion with international control centers, in 2011 partially adopted a system of measures, the main unit of which is foot.