International Bureau of Weights and Measure

Variations in the Force Due to Gravity. The mass of an object is the quantity of matter ia the object. It is a fundamental quantity that is fixed, and does not change with time, temperature, location, etc. The standard for mass is a platinum—iridium cylinder, called the International Kilogram, maintained at the International Bureau of Weights and Measures, ia Snvres, France. The mass of this cylinder is 1 kg by definition (9). AH national mass standards are traceable to this artifact standard. 

The International Bureau of Weights and Measures, BIPM (Parc de Saint-Cloud, France) is described in Appendix X2 of Ref 4. This bureau operates under the exclusive supervision of the International Committee for Weights and Measures (CIPM). 

Mass. The unit of mass is the kilogram and is the mass of a particular cylinder of Pt—Ir alloy which is preserved in France by the International Bureau of Weights and Measures. 

International Bureau of Weights and Measures PaviUion de Breteuil E-92310 Sevres, Prance... 

International Bureau of Weights and Measures Pavilion de Breteuil P-92310, Sevres, Prance International Electrotechnical Commission (lEC) 1 me de Varembe 1211 Geneve 20 Swit2edand International Organization for Standardization (ISO) 1 me de Varembe CH 1211, Geneve 20 Switzedand... 

This international prototype, adopted by the 1st and 3rd CGPM in 1889 and 1901, is a particular cylinder of platinum—iridium kept at the International Bureau of Weights and Measures near Paris. It is the only base unit still defined by an artifact. 

For scientific work the fundamental standard of mass is the international prototype kilogram, which is a mass of platinum-iridium alloy made in 1887 and deposited in the International Bureau of Weights and Measures near Paris. Authentic copies of the standard are kept by the appropriate responsible authorities in the various countries of the world these copies are employed for the comparison of secondary standards, which are used in the calibration of weights for scientific work. The unit of mass that is almost universally employed in laboratory work, however, is the gram, which may be defined as the one-thousandth part of the mass of the international prototype kilogram. 

The supplementary documents are Supplementary Information for the ITS-90. International Bureau of Weights and Measures Pavilion de Breteuil, F-92312 Sevres. France, 1990 Techniques for Approximating the ITS-90. International Bureau of Weights and Measures Pavilion de Breteuil, F-92312 Sevres, France, 1990. 

CIPM), which meets annually and oversees the work of the International Bureau of Weights and Measures (BIPM). The BIPM, based at Sevres just outside Paris, has the responsibility for international standards and is a center for international research and cooperation in metrology. The CIPM has created a number of advisory specialist committees (consultative committees) that are each chaired by a member of CIPM. The committee of interest to chemists is the Consultative Committee on the Amount of Substance (CCQM). It oversees the Avogadro project and coordinates a series of international interlaboratory trials called Key Comparisons (BIPM 2003), which... 

Welch, M J, Parris, R M, Sniegoski, L T, and May, W E (2001), CCQM-K6 Key Comparison on the determination of cholesterol in serum (Sevres, France International Bureau of Weights and Measures). 

BIPM (2006), The international system of units. Available http //www.bipm. fr/en/si/ (Sevres, International Bureau of Weights and Measures). 

KILOGRAM (kg). A unit of mass and is based upon a cylinder of platinum-iridium alloy kept by the International Bureau of Weights and Measures at Paris. A duplicate in the custody of the National Bureau of Standards at Washington is the mass standard for the United States. The kilogram is the only base unit still defined by an artifact. (A kilogram equals (1) 1,000 grams (2) 2.205 pounds (3) 9,842 x 10-4 long tons or (4) 1 102 x 10-3 short tons. 

Fig. 1 Metrological traceability and hierarchy of procedures and materials (according to ISO/IEC 17511). uc(y) Uncertainty BIPM International Bureau of Weights and Measures NMI National Metrology Institute ACL Accredited Calibration Laboratory MCL Manufacturer s Calibration Laboratory ML Manufacturer s Laboratory Mf Manufacturer...

National Bureau of Standards (NBS) Special Publication 420 (1975) The International Bureau of Weights and Measures 1875 to 1975, US Department of Commerce... 

The second, symbol s, is the SI unit of time, defined as the duration of 9,192,631,770 cycles of radiation associated with a specified transition of the cesium atom. The meter, symbol m, is the fundamental unit of length, defined as the distance light travels in a vacuum during 1/299,792,458 of a second. The kilogram, symbol kg, is the mass of a platinum/ iridium cylinder kept at the International Bureau of Weights and Measures at Sevres, France. The unit of temperature is the kelvin, symbol K, equal to 1/273.16 of the thermodynamic temperature of the triple point of water. A more detailed discussion of tern-perature, the characteristic dimension of thermodynamics, is given in Sec. 1.4. The measure of the amount of substance is the mole, symbol mol, defined as the amount of substance represented by as many elementary entities (e.g., molecules)... 

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