Metrology Symposium 2020 StevenMetrology Symposium 2020

The Metrology Symposium 2020 wasjointly organised by the Government Laboratory, the Hong Kong Council for Testing and Certification, School of Science and Technology of the Open University of Hong Kong, and the Standards and Calibration Laboratory of the Innovation and Technology Commission.


On 20 May 2019, the World Metrology Day (WMD) 2019, the International System of Units (SI) was revised so that all the seven base units, namely, the second, the metre, the kilogram, the ampere, the kelvin, the mole and the candela, were defined based on seven defining constants related to the fundamental laws of nature. The re-definition removes the instability imposed by the use of artefact standards and makes these SI base units “fundamentally better”. Hence, the official theme for WMD 2019 was chosen as “The International System of Units – Fundamentally better”. A poster designed by SCL was used globally to promote this event.

The revision of the SI enables the base units to be realized with accuracies limited only by the physical nature and our technical capability but not by their definitions. In recent year many innovative primary methods have been developed or refined for the practical realization of the base units using the law of physics. Some examples are the X-ray-crystal-density (XRCD) method for realization of the kilogram, the single electron transport (SET) method for realization of the ampere, the cryogenic radiometer for realization of the candela and the use of optical methods to realize the second. There were also numerous advances in the field of reference material and the metrology of chemistry and biology. The Symposium attempts to unfold to the local testing and certification industry as well as the parties interested in metrology how the revised SI can enable us to enhance the accuracy in measurement science and technology. Advance topics in the latest research and development related to the primary standards in various fields were discussed.