This forthcoming documentary traces the fascinating history of the kilogram, the redefinition, and features interviews with the guardians of the prototypes. Scientists around the world chase the realization of a 200-year-old challenge: to create a mass standard that will never change with time, or space.
Status of the film July 2021: I have started uploading tidier annotations for my references. I'm also tidying the edit.
Background on the kilogram In 1780, more than 40,000 different measures of length were in use in France for trading wool, corn, wood, all household staples. Every city and village had their own carved stone trade measures, stored at the local church.
The varying measures led to serious economic and trade problems, adding to the atmosphere of unrest in France. So, in 1787 King Louis XVI charged the French Academy of Science with the creation of a uniform set of measures.
In June 22, 1799 the meter and the kilogram were realized as physical objects; today these are kept secure at the International Bureau of Weights and Measures (BIPM) in Pavillon de Breteuil near Paris. The kilogram is stored under multiple glass lids; a speck of dust changes the kilogram's weight a tiny bit.
All current science and technology could not exist without the kilogram prototype, and the modern world needs a standard that is the everywhere the same. To realize this, the General Conference on Weights and Measures may redefine the kilogram as the calculated value of the Planck constant, the very same constant that revolutionized 20th-century physics in the form of transistors and computers. Today the speed of light is no longer a measured quantity, but rather a fixed value that implicitly defines the meter. Similarly, the Planck constant would define the kilogram and make the physical kilogram obsolete.