Fundamental metrology. Applied metrology

3 MINISTRY OF EDUCATION OF THE RUSSIAN FEDERATION NORTHWEST STATE CORRESPONDENCE TECHNICAL UNIVERSITY I. E. Ushakov, I. F. Shishkin APPLIED METROLOGY St. Petersburg 2002 4 MINISTRY OF EDUCATION OF THE RUSSIAN FEDERATION ACTIONS NORTH-WESTERN STATE CORRESPONDENCE TECHNICAL COURSE UNIVERSITY I.E. USA EDUCATIONAL INSTITUTIONS STUDYING IN THE SPECIALTY "METROLOGY AND METROLOGICAL SUPPORT") St. Petersburg 2002 5 UDC 389.004.12 (075.8) I.E. Ushakov, I.F. Shishkin. Applied metrology: Textbook. for universities. Ed. 4th, revised and additional -SPb.: SZTU, 2002, - 116 p. The textbook contains materials on the main sections and topics of the university program of the course of the same name. The types of metrological activities, their organization and content are considered. It reflects the latest regulatory and advisory documents in the field of metrology. The textbook is intended for university students studying in the direction of “Standardization, certification and metrology” (specialty 190800 – Metrology and metrological support), and can also be useful to employees of metrological services, engineering and technical staff and administrative and managerial personnel of enterprises. Reviewers: Department of Standardization, Metrology and Diagnostics of the Moscow State Academy of Instrument Engineering and Informatics (MGAPI) (head of the department – Firstov V.G., Dr. Tech.. sciences, prof.); D.F. Tartakovsky, Honored Worker of Science and Technology of the RSFSR, full member of the Metrological Academy, Doctor of Engineering. sciences, prof. Department of Technology and Materials, St. Petersburg State University of Telecommunications named after. A.M. Bonch-Bruevich. © Northwestern State Correspondence Technical University June 19, 1988 coincided with the beginning of perestroika in our country, which unfolded after the April (1985) Plenum of the CPSU Central Committee and the decisions of the 17th Congress of the CPSU. The restructuring of the economic mechanism based on the transition to economic management methods, the introduction of the USSR Law on State Enterprises, the widespread introduction of self-financing, self-financing and cooperation has an impact on all aspects of metrological activity. On November 21, 1988, the Council of Ministers of the USSR adopted Resolution No. 489 “On the restructuring of the activities and organizational structure of the USSR State Committee for Standards.” Under these conditions, studying applied metrology in accordance with established canons is inappropriate, and new approaches to metrological activities have not yet been defined. Therefore, until the release of a new textbook on applied metrology, planned for 1992, you can use this textbook, supplementing its content with experience from current metrological practice. Proposed tutorial This is the second edition, revised and expanded. The main content of the book is the types of metrological activities that relate to applied metrology for any economic mechanism. Organizational and legal basis Applied metrology is considered fragmentarily, since it is this area that is subject to the greatest changes. The purpose of teaching applied metrology is to prepare future specialists for practical metrological activities. Main goals academic discipline- in mastering the scientific and theoretical foundations of the specialty, consistent application of knowledge, skills and abilities when solving production tasks, metrological support of the national economy. As a result of studying applied metrology, a specialist must know the main types of metrological activities, be able to analyze the state of measurements at enterprises and organizations in the industry, metrological examination of normative and technical documentation, certification and standardization of measurement techniques, state tests and quality of products. He must have an idea about the future of applied metrology, directions for restructuring professional metrological activities based on the abandonment of comprehensive legal regulation, the development of independence, entrepreneurship and initiative, the use of highly effective economic methods management. 8 PREFACE to the third edition In the preface to the previous edition, it was noted that the dynamic processes of government reorganization have a direct impact on metrological activities. Indeed, over the past period, laws have appeared Russian Federation “On ensuring the uniformity of measurements”, “On standardization”, “On certification”, the Interstate Council for Standardization, Metrology and Certification was created, the “Agreement on the implementation of a coordinated policy in the field of standardization, metrology and certification”, “Agreement on mutual recognition of the results of state tests and type approval, metrological certification, verification and calibration of measuring instruments, as well as the results of accreditation of laboratories carrying out testing, verification and calibration of measuring instruments", the formation of national systems calibration, the number of regulatory and technical documents in the field of ensuring the uniformity of measurements is increasing. However, as noted, all changes affect primarily the organizational and legal aspects of metrological activities, which are studied in the course “Legal Metrology”. Contents of basic metrological works, such as analysis of the state of measurements, examination of normative and technical documentation, standardization and certification of measurement methods, state tests, metrological certification and verification of measuring instruments, metrological support of production products remain virtually unchanged. Innovations such as calibration of measuring instruments, certification, etc. do not change the essence of the matter. We can say that applied metrology as a discipline that studies the types of practical metrological activities that ensure the necessary quality and uniformity of measurements under any socio-political system and socio-economic structure has been finally formed. Compared to the previous edition, significant changes have been made to the material. The section on State acceptance of products has been excluded. This purely administrative measure, aimed at improving the quality of industrial products, did not justify itself and was canceled by the decision of the First Congress of People's Deputies of the RSFSR in 1990. A section on control is included. Control as a check of compliance with the norm is either a measurement on an order scale or uses the results of measurements performed earlier. Attributing it to metrological practice expands the scope of activity of metrologists and improves the structure of production. Finally, the material has been updated in accordance with the updated regulatory and technical documentation. The process of updating the scientific and technical documentation will continue, so when studying applied metrology, in addition to educational literature, it is mandatory to use the scientific and technical documentation funds that are available at each university. 9 PREFACE to the fourth edition The previous edition was prepared immediately after the adoption of the law of the Russian Federation “On ensuring the uniformity of measurements” (1993). Over the past period, in pursuance of this law, a number of regulatory and advisory documents have been developed and approved, regulating various types of metrological activities. Row regulatory documents in the area of training “Standardization, certification and metrology”. Within the framework of this direction, specialists are trained in the following specialties: 072000 - Standardization and certification, 190800 - Metrology and metrological support. The discipline "Applied Metrology" is included in the block of special disciplines for the specialty "Metrology and Metrological Support". The nomenclature and content of disciplines for this specialty differs in many respects from those available in curriculum specialty 19.06 - "Metrology, standardization and quality management", which was the focus of the previous edition. Compared to the previous edition, significant changes have been made to the content. Sections whose materials are devoted to control and certification are excluded. The study of these materials is carried out within the framework of the relevant disciplines: “Metrology, standardization and certification”, “Statistical methods of quality control and management”, “Qualimetry and quality management”. Sections devoted to metrological control and supervision have been introduced; licensing the activities of legal entities and individuals in the production, repair, sale and rental of measuring instruments; analysis of the state of measurements, control and testing. In addition, the materials are presented in accordance with the requirements of updated regulatory and advisory documentation. When studying this discipline, as before, in addition to educational literature, it is mandatory to use scientific and technical documentation funds. 10 BASIC ABBREVIATIONS AND NOTATIONS VNIIMS – All-Russian Scientific- Research institute metrological service. GM is the chief metrologist. MMC - state metrological control. GMKN - state metrological control and supervision. GMN - state metrological supervision. GMS – State Metrological Service. SSMC is a state scientific metrological center. GOU is a state governing body. GSVCH – Civil service tests. MVI is a measurement technique. MGS – Interstate Council for Standardization, Metrology and Certification. MD is an international document. MO – metrological support. OIML – International Organization of Legal Metrology. MR – international recommendation. Minimum wage is the minimum wage. MS – metrological service. MX – metrological characteristic. ND - regulatory documents. R&D – research and development work. NTD - normative and technical documentation. NTK – Scientific and Technical Commission for Metrology and Measuring Equipment of the State Standard of Russia. RSK – Russian system calibration. RF - Russian Federation. SI – measuring instrument(s). RM - standard sample (standard samples) of the composition and properties of substances and materials. CIS - Commonwealth of Independent States. TK - technical specifications. TO – technical description. 11 INTRODUCTION In accordance with the practice of metrological activities and accepted terminology: Applied metrology is a section of metrology, the subject of which is questions practical application developments of theoretical metrology and provisions of legal metrology. Current state applied metrology and the prospects for its development are associated with the rejection of comprehensive regulatory regulation, the development of independence, entrepreneurship and initiative, and the use of highly effective economic management methods in the context of the transition to market relations. It is necessary to note the importance for future metrological engineers of acquiring knowledge and acquiring practical skills in the main types of metrological activities. The purpose of studying the discipline is to prepare the future metrology engineer for the practical organization and implementation of the main types of metrological work, including analysis of the state of measurements, control, testing, and the development on its basis of proposals for improving metrological support. Main tasks - obtaining for the manufacture, repair, sale and rental of measuring instruments; development of measurement techniques; analysis of the state of measurements, control, testing at the enterprise. As a result of studying the discipline, the student must know the organization and procedure for carrying out the main types of metrological work, be able to organize the implementation of such work, including the registration of their results, taking into account the established requirements. metrological activities. The first section discusses the organization and conduct of State metrological control and supervision, as well as metrological control and control carried out by metrological services of legal entities. The second section is devoted to testing and type approval of measuring instruments, including the development of testing programs for measuring instruments and accreditation of State testing centers for measuring instruments. Work on verification of measuring instruments, including the development of verification methods, certification of verifiers and accreditation of metrological services of legal entities for the right to verify measuring instruments, is discussed in the third section. The fourth section is devoted to the study of work related to licensing the activities of legal entities and individuals in the manufacture, repair, sale and rental of measuring instruments. The development, certification and standardization of measurement methods, as well as the accreditation of metrological services of legal entities for the right to certify measurement methods are discussed in the fifth section. The sixth section is devoted to the study of issues of organizing and conducting calibration of measuring instruments. The seventh section discusses issues of analyzing the state of measurements, control and testing at an enterprise (organization), including the development of proposals for improving metrological support.

The appendices contain: forms for presenting source materials for analyzing the state of measurements, control, and testing at an enterprise (organization) - Appendix 1; classifiers of types of measurements and types of reference materials for the composition and properties of substances and materials - Appendix 2; form of certificate on the state of metrological support at the enterprise (organization) - Appendix 3; list of regulatory documentation - Appendix 4. Metrology is the science of measurements, methods of achieving their unity and the required accuracy. The word "metrology" is formed from two Greek words : “metron” – measure and “logos” – teaching. The literal translation of the word “metrology” is the study of measures. For a long time, metrology remained mainly a descriptive science about various measures and the relationships between them. Measurement

– a cognitive process consisting of comparing a given value with a known value taken as a unit.

Measures in Rus': length - arshin, fathom (3 arshins), verst; weight – pood (16.4 kg); liquid bodies - barrels, buckets, mugs, bottles.

In the XV–XVIII centuries. In connection with the rapid growth of science, the need arose for measurements (barometers, hydrometers, pressure gauges (water pressure), steam engines (power is measured in horsepower)).

In the 19th–20th centuries. new physical discoveries occur, the need arises for measurements in atomic and molecular physics. In 1827, a commission of exemplary weights and measures was formed in Russia. DI. Mendeleev played a large role in the development of the metrological service, heading it from 1892 to 1907. In 1970, the USSR State Standard was formed, in 1993, the State Standard was transformed into the Russian State Standard.

In the modern understanding, metrology is the science of measurements, methods and means of ensuring their unity and methods of achieving the required accuracy. The main areas of metrology include:

general measurement theory;
units physical quantities and their systems;
methods and means of measurement; methods for determining measurement accuracy;
fundamentals for ensuring the uniformity of measurements and uniformity of measuring instruments;
standards and exemplary measuring instruments; methods for transferring unit sizes from standards and reference measuring instruments to working measuring instruments.

The main legislative document in metrology is the Law “On Ensuring the Uniformity of Measurements”, adopted in 1992, which is aimed at protecting the rights and interests of citizens and the country’s economy from the negative consequences of unreliable measurement results.

Metrology is divided into theoretical, applied and legislative.

Theoretical metrology deals with issues basic research, creation of a system of units of measurement, physical constants, development of new measurement methods.

Applied (practical) metrology deals with issues of practical application in various fields activities of the results of theoretical research within the framework of metrology.

Legal metrology includes a set of interdependent rules and norms aimed at ensuring the uniformity of measurements, which are elevated to the rank legal provisions(by authorized government bodies), are binding and are under the control of the state. Its main task is to create and improve the system state standards, which establish rules, requirements and standards that determine the organization and methodology of work to ensure the uniformity and accuracy of measurements, as well as the organization and functioning of the corresponding

The appendices contain: forms for presenting source materials for analyzing the state of measurements, control, and testing at an enterprise (organization) - Appendix 1; classifiers of types of measurements and types of reference materials for the composition and properties of substances and materials - Appendix 2; form of certificate on the state of metrological support at the enterprise (organization) - Appendix 3; list of regulatory documentation - Appendix 4. is the science of measurements, methods of achieving their unity and the required accuracy. The word “metrology” is formed from two Greek words: “metron” - measure and “logos” - doctrine. The literal translation of the word “metrology” is the study of measures. For a long time, metrology remained mainly a descriptive science about various measures and the relationships between them. : “metron” – measure and “logos” – teaching. The literal translation of the word “metrology” is the study of measures. For a long time, metrology remained mainly a descriptive science about various measures and the relationships between them. – cognitive process, which consists in comparing a given value with a known value taken as a unit.

The subject of metrology is the processing of quantitative information about the properties of objects and processes with a given reliability.

Measures in Rus': length - arshin, fathom (3 arshins), verst; weight – pood (16.4 kg); liquid bodies- barrels, buckets, mugs, bottles.

In the XIX–XX centuries. New physical discoveries are taking place, and there is a need for measurements in atomic and molecular physics. In 1827, a commission of exemplary weights and measures was formed in Russia. DI. Mendeleev played a large role in the development of the metrological service, heading it from 1892 to 1907. In 1970, the USSR State Standard was formed, in 1993, the State Standard was transformed into the Russian State Standard.

In the modern understanding, metrology is the science of measurements, methods and means of ensuring their unity and methods of achieving the required accuracy. The main areas of metrology include:

– general theory of measurements;

– units of physical quantities and their systems;

– methods and means of measurement; methods for determining measurement accuracy;

– fundamentals for ensuring the uniformity of measurements and uniformity of measuring instruments;

– standards and exemplary measuring instruments; methods for transferring unit sizes from standards and reference measuring instruments to working measuring instruments.

Metrology is divided into theoretical, applied and legislative.

Theoretical metrology deals with issues of fundamental research, the creation of a system of units of measurement, physical constants, and the development of new measurement methods.

Applied (practical) metrology deals with issues of practical application in various fields of activity of the results of theoretical research within the framework of metrology.

Legal metrology includes a set of interdependent rules and norms aimed at ensuring the uniformity of measurements, which are elevated to the rank of legal provisions (by authorized bodies state power), are binding and under the control of the state. Its main task is to create and improve a system of state standards that establish rules, requirements and norms that determine the organization and methodology of work to ensure the uniformity and accuracy of measurements, as well as the organization and functioning of the relevant public service.

Since ancient times, people have had a need to measure time, distance, size and weight of objects. As humanity developed, it created and improved measuring instruments and measurement methods. Today, not a single area of human activity can do without a variety of measurements. The most important role they play a role in improving product quality, controlling technological processes, production management, scientific research. Basically anyone scientific experiment This is a measurement of certain quantities. No wonder D.I. Mendeleev wrote:

“Science begins as soon as they begin to measure.”

Therefore, such a vast area of knowledge could not help but be systematized and formed as a full-fledged scientific direction. It is to define this direction that the concept of “metrology” is used.

The word “metrology” itself comes from the Greek words “ metron" - measure and " logo"- teaching. At first, the doctrine developed as a science about measures and relationships between various quantities of measures (used in different countries), and was descriptive (empirical).

To date metrology is the science of measurements, methods and means of ensuring their unity and ways of achieving the required accuracy. This definition give all Russian regulatory legal acts from and to recently adopted recommendations.

Goals and objectives of metrology

Objectives of metrology , as a science - ensuring the uniformity of measurements (UME); extraction of quantitative information about the properties of an object, the surrounding world, and processes with a given accuracy and reliability.

Objectives of practical metrology – , i.e. establishment and application of scientific and organizational foundations, technical means, rules and regulations necessary for OI and the required accuracy of measurements.

Metrology tasks:

implementation public policy in OEI;
development of a new and improvement of the current regulatory framework for OI and metrological activities;
formation of units of quantities (MU), systems of units, their unification and recognition of legality;
development, improvement, maintenance, comparison and application of state primary standards of units of quantities;
improvement of methods (measurement principles) of transferring units of measurement from the standard to the measured object;
development of methods for transferring the sizes of units of quantities from primary and working measurement standards to working SI;
maintaining the Federal Information Fund for OEI and providing the documents and information contained therein;
rendering public services according to OEI in accordance with the scope of accreditation;
establishment of rules and regulations for testing measuring instruments;
development, improvement, standardization of methods and measuring instruments, methods of determining and increasing their accuracy;
development of methods for assessing errors, the state of measuring instruments and control;
improvement general theory measurements.

In accordance with the objectives, metrology is divided into theoretical, applied, legislative and historical metrology.

Theoretical or fundamental metrology is engaged in the development of theory, problems of measuring quantities, their units, and measurement methods. Theoretical metrology is working on common problems arising when performing measurements in a particular field of technology, humanities, and even at the junction of many, sometimes very diverse areas of knowledge. Metrologists - theorists can deal, for example, with issues of measuring linear dimensions, volume and gravity in n - dimensional space, develop methods for instrumental assessment of radiation intensity cosmic bodies in relation to the conditions of interplanetary flights, or create completely new technologies that make it possible to increase the intensity of the process, the level of accuracy and its other parameters, to improve technical means, involved in it, etc. One way or another, almost any undertaking in any activity begins with theory and only after such elaboration moves into the sphere of specific application.
Applied or practical metrology deals with issues of metrological support, practical use of developments theoretical metrology, implementation of legal metrology provisions. Its task is to adapt general provisions and theoretical calculations of the previous section to a clearly defined, highly specialized production or scientific problem. So, if you need to assess the strength of the motor shaft, calibrate large quantities bearing rollers, or to provide, for example, comprehensive metrological control in the process of laboratory research, practitioners will select the appropriate technology from a large number of already known ones, process it, and possibly supplement it in relation to these conditions, determine the necessary equipment and tools, quantity and qualifications personnel, and will also analyze many other technical aspects of a particular process.
Legal metrology establishes mandatory legal and technical requirements for the use of standards, units of quantities, methods and measuring instruments aimed at ensuring the uniformity of measurements (UMU) and their required accuracy. This science was born at the intersection of technical and public knowledge and is designed to provide unified approach to measurements performed in all areas without exception. Legal metrology also directly borders on standardization, ensuring the compatibility of technologies, measuring instruments and other attributes of metrological support both domestically and internationally. international level. The area of interest of legal metrology includes work with standards of measurement quantities, issues of verification of measuring instruments and equipment, and training of specialists, as well as many other issues. Main legal document regulating activities in this area is. The regulatory legal framework also includes a number of by-laws, provisions and technical regulations that specify the legislative requirements for certain areas and types of activities of lawyers - metrologists.
Historical metrology designed to study and systematize units and measurement systems used in the past, technological and instrumental support for parameter control physical objects and processes, historical organizational - legal aspects, statistics and much more. This section also examines the history and evolution of monetary units, tracking the relationship between their systems, formed in the conditions various societies and cultures. Historical metrology, in parallel with numismatics, studies monetary units already because during the period of the birth of measurements as such, the elementary fundamentals of methods for assessing value and other parameters completely unrelated to monetary calculations largely repeated each other.
On the other hand, historical metrology is not a purely social branch of science, because often with its help, lost, but nevertheless relevant today measuring technologies are restored, development paths are tracked based on past experience and promising changes in this area are predicted, new ones are developed engineering solutions. Often, progressive methods for assessing any parameters are the development of already known ones, reworked taking into account new capabilities modern science and technology. Studying history is necessary to work with measurement standards in relation to their development and improvement, ensuring the compatibility of traditional and promising methods, as well as systematizing practical developments for the purpose of their use in the future.

A little about the history of the development of metrology

The history of metrology is part of the history of the development of reason, productive forces, statehood and trade; it matured and improved along with them. Thus, already under the Grand Duke Svyatoslav Yaroslavovich, an “exemplary measure” began to be used in Rus' - the prince’s “golden belt”. Samples were kept in churches and monasteries. At Novgorod prince Vsevolod was ordered to review the measures annually, and punishment was applied for non-compliance - up to and including the death penalty.

The “Dvina Charter” of 1560 by Ivan the Terrible regulated the rules for storing and transferring the size of bulk substances - octopus. The first copies were in orders of the Moscow state, temples and churches. Work on the supervision of measures and their verification was carried out at that time under the supervision of the Pomernaya Hut and the Great Customs House.

Peter I allowed English measures (feet and inches) to be used in Russia. Tables of measures and relationships between Russian and foreign measures were developed. The use of measures in trade, in mining mines and factories, and at mints was controlled. Admiralty - the board took care of correct use measures of goniometer instruments, compasses.

In 1736, the Commission of Weights and Measures was formed. The original measure of length was the copper arshin and the wooden fathom. The pound bronze gilded weight is the first legalized state standard. Iron arshins were made by order of Tsarina Elizabeth Petrovna in 1858.

On May 8, 1790, France adopted the meter as a unit of length - one forty-millionth of the earth's meridian. (It was officially introduced in France by decree of December 10, 1799)

In Russia in 1835, standards of mass and length were approved - the platinum pound and the platinum fathom (7 English feet). 1841 is the year the Depot of Exemplary Weights and Measures was opened in Russia.

On May 20, 1875, the Meter Convention was signed by 17 states, including Russia. International and national prototypes of the kilogram and meter have been created. (Metrologist Day is celebrated on May 20).

Since 1892, the Depot of Exemplary Weights and Measures was headed by the famous Russian scientist D.I. Mendeleev. In metrology, the Mendeleev era is usually called the period from 1892 to 1918.

In 1893, on the basis of the Depot, it was established Main Chamber weights and measures - metrological institute, where tests and verification of various measuring instruments were carried out. (Mendeleev headed the Chamber until 1907). Currently it is the All-Russian Scientific Research Institute of Metrology named after D.I. Mendeleev.

Based on the Regulations on Weights and Measures of 1899 in different cities Another 10 testing tents were opened in Russia.

The 20th century, with its discoveries in mathematics and physics, turned M into a science of measurements. Nowadays, the state and formation of metrological support largely determines the level of industry, trade, science, medicine, defense and development of the state as a whole.

The metric system of weights and measures was introduced by the decree of the Council of People's Commissars of the RSFSR dated September 14, 1918 (it began the “normative stage” in Russian metrology). Accession to the International Metric Convention occurred in 1924, as well as the creation of a standardization committee in Russia.

1960 - The International System of Units was created. In the USSR, it began to be used in 1981 (GOST 8.417 - 81). 1973 – The State System for Ensuring the Uniformity of Measurements (GSI) was approved in the USSR.

1993 adopted: the first law of the Russian Federation “On ensuring the uniformity of measurements”, the laws of the Russian Federation “On standardization” and “On certification of products and services”. Responsibility for violation established legal norms and mandatory requirements of standards in the field of uniformity of measurements and metrological support.

Legal metrology.

The main goals and objectives of ensuring the uniformity of measurements in production and science.

Metrological rules and norms of legal metrology are harmonized with the recommendations and documents of relevant international organizations. Thus, legal metrology contributes to the development of international economic and trade relations and promotes mutual understanding in international metrological cooperation.

6 Metrology – scientific basis GSI.

Metrology - scientific basis State system ensuring the uniformity of measurements (GSI)

Metrology is the scientific basis of GSI. Metrology is the science of measurements, methods and means of ensuring their unity and the required accuracy. “Metro” - measure (Greek), “logos” - doctrine (Greek).

Modern metrology includes three types:

a)legal metrology;

b) fundamental (scientific) metrology;

c) practical (applied) metrology.

Legal metrology is a section of metrology that includes complexes of interrelated and interdependent general rules, as well as other issues that require regulation and control by the state, aimed at ensuring the uniformity of measurements and the uniformity of measuring instruments.

Legal metrology serves as a means government regulation metrological activities through laws and legislative provisions that are put into practice through the State Metrological Service (SMS) and metrological services government agencies management and legal entities.

The field of legal metrology includes testing and type approval of measuring instruments (MI), state metrological control and supervision of MI, as well as measures to actually ensure the uniformity of measurements. One of the main tasks of metrology is to ensure the uniformity of measurements. This problem can be solved if two fundamental conditions are met

Expression of measurement results in common legal units;

Establishment of permissible errors of measurement results and limits beyond which they should not exceed at a given probability.

Fundamental and practical metrology appeared in ancient times. IN Ancient Rus' the basis of the system of measures were ancient Egyptian units of measurement, borrowed from Ancient Greece and Rome. The names of the units and their sizes corresponded to the possibility of making measurements using “improvised” methods, without resorting to special devices. So, in Rus' the units of length were in different time:

Elbow (from the bend of the elbow to the end of the middle finger);

Span (distance between the ends of the thumb and index finger

adult);

arshin (its appearance led to the disappearance of the span - V4 arshin);

oblique fathom = 248 cm.

By decree of Peter 1, Russian measures of length were agreed upon with English ones:
- inch (“finger” = 2.54 cm);

English foot = 12 inches = 30.48 cm. First metric system measures were introduced in France in 1840. Its importance was emphasized by D.I. Mendeleev as a means of promoting the “future desired rapprochement of peoples.” With the development of science and technology, new measurements and new units of measurement were required, which stimulated the development of fundamental and applied metrology. Initially, the prototype of units of measurement was sought in nature, studying macro-objects and their movement. So, a second is part of a period

rotation of the Earth around its axis. Gradually, the search moved to the atomic and intra-atomic level. Now a second is the duration of 9192631770 periods of radiation corresponding to the transition between two levels ultrafine structure the ground state of the Cesium-133 atom in the absence of disturbance from external fields. Thus, metrology, as a science, is dynamically developing. Further development of fundamental metrology is confirmed by the definitions of units of physical quantities (PV) adopted in the International System of Units of Physical Quantities (SI system), giving an idea of nature, natural origin accepted PV units. The system of units of physical quantities - * is a set of basic and derived units of physical quantities. The General Conference on Weights and Measures (GCPM) in 1954 defined six basic units of physical quantities for their use in international relations: meter, kilogram, second, ampere, degree Kelvin, candle. In 1960, the XI CGPM approved International system units of physical quantities (SI system), which was adopted by all major international organizations in metrology. In the USSR, this SI system was adopted in 1993. Basic units of the SI system: .

a) unit of length - meter - the length of the path that light travels in a vacuum in 1/299792458 of a second;

b) unit of mass - kilogram - c) unit of time - second -

d) unit of force electric current- ampere - the power of an unchanging
current, which when passing through two parallel conductors
infinite length and negligibly small circular cross-section, located on
at a distance of 1 m from each other in a vacuum, would create between these conductors
a force equal to 2-10" N per meter of length;

e) unit of thermodynamic temperature - degree Kelvin -
1/273.16 part of the thermodynamic temperature of the triple point of water
(use of the Celsius scale is allowed);

f) unit of amount of substance - mole - amount of substance g) unit of luminous intensity - candela - luminous intensity in given direction
source