520- WORLD METROLOGY DAY

On May 20, 1875, 17 countries signed "the metre Convention" in Paris, France, this is a in the global scope of the international system of units and ensure the measurement results consistent with the intergovernmental agreement. 1999 October 11 to 15, the 21st session of the general conference of weights and measures in Paris, France international metrology bureau held in order to make the governments and the public understand measurement, encourage and promote the development of the countries in the field of measurement, strengthen the countries in the field of measurement of international exchanges and cooperation, the general assembly to determine the annual May 20 for world metrology day and get the recognition of the international organization of legal metrology.

In real life, work, measurement time exists, measurement is the support of social, economic and scientific and technological development of the important foundation. Modern measurement includes scientific measurement, legal metrology and engineering measurement. Scientific measurement is the development and establishment of measurement standard device, provide value transfer and traceability basis; legal metrology is the people's livelihood of the important measurement instruments and commodities measurement behavior in accordance with the law supervision, to ensure that related to the accuracy of the values of quantities; engineering measurement is for other measurement activities of the whole society value traceability provide calibration and testing services. Everyone needs to measure, always inseparable from the measurement, every year this day, many countries will in various forms to celebrate, such as participating in measurement, and to the public especially the young students open the metrology laboratory, exhibition of measurement, newspapers and magazines, open column, published a special issue, popularize knowledge measurement, strengthening the propaganda of the measurement, to arouse the concern of the whole society on the measurement, the measurement in promoting the development of science and technology and national economy play a greater role. The theme of this year's world metrology day is "measurement and light", organized around the theme activities, and the first time issued a "world metrology day" commemorative stamps.

"World metrology day" makes the human awareness of measurement to be on a new height, and the measuring impact of society into a new stage.