metric system
(redirected from Metric conversions)Also found in: Dictionary, Thesaurus, Medical.
metric system
Metric system
A system of units used in scientific work throughout the world and employed in general commercial transactions and engineering applications in most of the developed nations of the world except for the United Kingdom and the United States. The basic units of the metric system define length (meter), mass (kilogram), and time (second).
The chief advantage of the metric system is that it is based on standards that have been accepted by international agreement, and it therefore provides a common basis for all scientific measurements. A second advantage of the metric system lies in the fact that only decimal multiples and submultiples of the fundamental length and mass units and of other derived units are employed. See Physical measurement, Time, Units of measurement
metric system
[′me·trik ‚sis·təm]Metric System
(decimal system), a set of units for physical quantities based on the meter as the unit of length. Originally, the metric system also included units of area (the square meter), volume (the cubic meter), and weight (the kilogram; the weight of 1 cubic decimeter of water at 4°C), as well as the liter (for capacity), the are (for the area of plots of land), and the ton (1,000 kg). An important distinctive feature of the metric system was the method of forming multiple and fractional units in decimal ratios; the prefixes kilo-, hecto-, deca-, deci-, centi-, and milli- were adopted to form the names of the derived units.
The metric system was developed in France during the era of the French Revolution. According to a proposal by a commission of leading French scientists (J. Borda, M. Condorcet, P. Laplace, and G. Monge), the meter was adopted as the unit of length and made equal to one ten-millionth of one-quarter of the length of the geographical meridian passing through Paris. This decision resulted from the attempt to provide as a basis for the metric system an easily reproducible “natural” unit of length, which was related to some natural object that was for all practical purposes unchanging. The decree on the introduction of the metric system in France was passed on Apr. 7, 1795. In 1799 a platinum prototype meter was made and approved. The sizes, names, and definitions of the other units of the metric system were chosen in such a way that the system would have no national characteristics and could be adopted by all countries. The metric system became truly international in nature in 1875, when 17 countries, including Russia, signed the Metric Treaty for the provision of international standardization and the improvement of the metric system. The system was authorized for use in Russia (on an optional basis) by a law of June 4, 1899, which was drafted by D. I. Mendeleev, and it was made mandatory by a decree of the Council of People’s Commissars of the RSFSR on Sept. 14, 1918. It was made mandatory for the USSR by a resolution of the Council of People’s Commissars of the USSR on July 21, 1925.
An entire series of special systems of units covering only particular fields of physics and engineering, and also individual subsidiary units, has arisen on the basis of the metric system. The development of science, engineering, and international communications has led to the creation of the International System of Units, a unified system of units based on the metric system that covers all fields of measurement; it has now been made mandatory or is preferred by many countries.
REFERENCES
Isakov, L. D. Na vse vremena, dlia vsekh narodov. Petrograd, 1923.Burdun, G. D. Edinitsy fizicheskikh velichin. Moscow, 1967.
Shirokov, K. P. “50-letie metricheskoi sistemy v SSSR.” IzmeriteVnaia tekhnika, 1968, no. 9.
Stille, U. Messen und Rechnen in der Physik. Braunschweig, 1961.