Metrology

Metrology is the scientific study of <a href="/facts/Measurement/rsLLbn1s">measurement</a>. It establishes a common understanding of <a href="/facts/Unit_of_measurement/pvTpWbmC">units</a>, crucial in linking human activities. Modern metrology has its roots in the <a href="/facts/French_Revolution/PIkDlrC0">French Revolution</a>'s political motivation to standardise units in France when a length standard taken from a natural source was proposed. This led to the creation of the decimal-based <a href="/facts/Metric_system/to24H0YK">metric system</a> in 1795, establishing a set of standards for other types of measurements. Several other countries adopted the metric system between 1795 and 1875; to ensure conformity between the countries, the <a href="/facts/International_Bureau_of_Weights_and_Measures/tPEu4X0s">Bureau International des Poids et Mesures</a> (BIPM) was established by the <a href="/facts/Metre_Convention/CpK3VJVv">Metre Convention</a>. This has evolved into the <a href="/facts/International_System_of_Units/S7YLglNz">International System of Units</a> (SI) as a result of a resolution at the 11th <a href="/facts/General_Conference_on_Weights_and_Measures/a1FPjTtr">General Conference on Weights and Measures</a> (CGPM) in 1960.
Metrology is divided into three basic overlapping activities: 

<ul><li>The definition of units of measurement</li>
<li>The realisation of these units of measurement in practice</li>
<li>Traceability—linking measurements made in practice to the reference standards</li></ul>
These overlapping activities are used in varying degrees by the three basic sub-fields of metrology: 

<ul><li>Scientific or fundamental metrology, concerned with the establishment of units of measurement</li>
<li>Applied, technical or industrial metrology—the application of measurement to manufacturing and other processes in society</li>
<li>Legal metrology, covering the regulation and statutory requirements for measuring instruments and methods of measurement</li></ul>
In each country, a national measurement system (NMS) exists as a network of laboratories, <a href="/facts/Calibration/xkqmdeVl">calibration</a> facilities and accreditation bodies which implement and maintain its metrology infrastructure. The NMS affects how measurements are made in a country and their recognition by the international community, which has a wide-ranging impact in its society (including economics, energy, environment, health, manufacturing, industry and consumer confidence). The effects of metrology on trade and economy are some of the easiest-observed societal impacts. To facilitate fair trade, there must be an agreed-upon system of measurement.

Metrology open-in-new

Metrology