This forthcoming documentary series 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 September 2021: I've decide to turn the "Kilofilm" into a series! I think there are too many interesting people, ideas, and aspects of the kilogram to arbitrarily toss them out to only show the "important parts". The current edit is 244 minutes of running time, from 260 hours of raw footage. That makes about one minute per hour (60:1) which is a common ratio in documentary films. (I wasn't aiming for that ratio, but that how it turned out.)
Turning the material into episodes doesn't mean that there's a "physics" episode, or a "history" episode. The past story of the kilogram informs the present state of the unit. So I've arranged the episodes instead to express one definition (or conception) of the kilogram over time. For example, the first episode looks at how the IPK was developed and why; that is, the Kilogram of 1875-2018. The second episode looks at the kilogram as the bottom of the traceability chain of weights in commerce. The third episode looks at the kilogram as one of the French Revolutionary reforms to an inefficient commerce infrastructure. You get the idea.
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.