The State of the Unit: a documentary film about the redefinition of the kilogram

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.

Since the retirement of the meter, the kilogram prototype is the only human-made measurement standard. Forever it will be for science what Cervantes did for literature and Goya did for painting: the foundation of modern instances.

And one hundred years from today, the kilogram prototype might well become mankind's most treasured artifact.

Director’s statement

My current film is about the kilogram. When I tell people that, some ask "What is there to say about the kilogram?" And others wonder, "How can you fit everything in only one film?"

Well, I had in mind a shorter film about how The Kilogram (a specific platinum-iridium cylinder in a vault in Paris) is losing weight, and what that really means.

But I found there's much more to the story.

In my film, I aim to bridge measurements from daily life to these efforts to re-define the kilogram at some of the major scientific players including NIST in Gaithersburg, CNAM and LNE in Paris, and PTB in Braunschweig, Germany. With this new definition, they hope to fulfill a 100-year-old dream of some of the greatest physicists of all times. And I aim to show the social and cultural relevance behind our measures.

I hope that you find the history and redefinition of the kilogram as fascinating as I do.

About the Director

Amy Young graduated from CalArts with an MFA in Film Directing. She began work on the The State of the Unit as part of an documentary film exchange program at La Fémis in Paris, France.