Big news and the metric system

Kilogram replica

This replica of a kilogram is on  display at the National Institute of Standards and Technology, which is part of Department of Commerce. The domes are to protect it from environments that might alter it.

First, the kilogram vote passed on Friday! We now have a scientifically defined kilogram. Second, I was interviewed by Vox News for their daily podcast on Friday, November 16, 2018. I’m in the second half of the interview.

The metric system (or SI as it is known around the world) was first implemented in France back in 1795. Since then, almost every country in the world has adopted this set of measures with the United States being one of the few holdouts from full adoption. (The others are Liberia and Burma/Myanmar.)

Back In 1799 the meter was defined by a prototype meter bar. Later, a scientific standard for the meter was defined in 1960, and was redefined in 1983. It is currently the length of the path that light travels in a vacuum in 1/299,792,458 of a second.

If you have the precision equipment to make that measurement, all those “meters” around the world are exactly the same.

In contrast

To this day, the definition of the kilogram is a carefully protected platinum-iridium prototype that is the kilogram. It is held by the International Bureau of Weights and Measures (or the Bureau International Poids et Mesures) outside of Paris. Should anything happen to that physical standard it could theoretically change what the kilogram is around the world.

Having a physical standard/prototype has inherent problems. There are additional physical standards or “artifacts” that are stored around the world which are periodically compared to the one in France to make sure they all have the same mass. However, over time, the duplicate kilograms have “drifted” away from that the one in France. (Several of these prototypes are held by our own National Institute of Standards and Technology in Maryland.) That’s a problem when things like oils from people’s skin or even dust could impact its mass if it is not perfectly protected. And perfect, in this sense, is impossible.

As a result, a scientifically defined standard has been sought—until recently—without success. Much of this quandary was captured in Robert P. Crease’s book, World in the Balance: The Historic Quest for an Absolute System of Measurement, which was published in 2012.

Crease relates that two different technologies were being applied to solve the problem of creating the kilogram in the laboratory. One was the “Avogadro method” that “…realizes the mass unit using a certain number of atoms…”

(I’m not going to go into a lot of detail here because I’ve yet to understand it myself.)

Crease also relates…

The “watt balance” approach, on the other hand, ties the mass unit to the Planck constant, via a special device that exploits the equality of SI units of mechanical and electrical power. p. 255

(Again, very complicated.)

You can read a Vox News story that explores more of the science here.

Today, on November 16, the International Bureau (of which the U.S. is a member) will vote to determine if the scientific standard for the kilogram will be based on the “watt balance” method.

Should that occur (and it is expected to pass) the new standard, will go into effect on May 20, 2019.

Why May 20 next year? Because May 20 is the 144th anniversary of the signing of the 1875 Treaty of the Meter. That document gave the General Conference on Weights and Measures “…the international authority that ensures wide dissemination of the SI and modifies the SI as necessary to reflect the latest advances in science and technology.”

This is a developing story so stay tuned to this page for further developments.

Linda

American Metric System Hypocrisy?

Start planning your World Metrology Day celebration now!

Start planning your World Metrology Day celebration now!

May 20 will be the 139th anniversary of the United States as one of the original signatory nations of the Convention of the Meter also known as the Treaty of the Meter. On that day the world took a leap forward and officially recognized the need to protect and improve the metric system (or SI as it is known on the rest of the planet), through the creation of the International Bureau of Weights and Measures (BIPM). It is an intergovernmental organization that comes under the authority of the General Conference on Weights and Measures (CGPM) and the supervision of the International Committee for Weights and Measures (CIPM). On that day in Paris there was agreement on how the organization would be financed and managed, with member governments acting in common accord on all matters.

Ahem, then there’s the United States saying one thing and doing another

Despite:

yet, I’m still buying my hamburger by the pound, gasoline by the gallon and fabric by the yard. What’s wrong with this picture?

Plenty and that’s why I’ve been researching his topic for almost two years. I trust the documentary I plan to make will raise awareness of how far behind the rest of the world we’ve gotten and we’ll want to do something about it.

To commemorate this 139th anniversary, also known as World Metrology Day, I’ll give a talk at Mesa Public Library in Los Alamos, New Mexico on May 21 (Wednesday) at 6 p.m. The talk is free and open to the public. If you’re in the neighborhood, I hope you’ll drop by. I’ll try to be both informative and entertaining.

Just so you know, the theme for this year’s World Metrology Day is “Measurements and the global energy challenge” and is sponsored by the BIPM and the International Organization of Legal Metrology (BIML).

According to Stephen Patoray, the current director of the BIML:

While measurements are central to most basic decisions on energy usage, there are many other aspects of the global energy challenge which are much more complex:

  • global population growth;
  • emerging economies;
  • complex technologies;
  • increasing consumer demands;
  • higher quality of life;
  • etc.

According to the site’s press release:

World Metrology Day is an annual event during which more than 80 countries celebrate the impact of measurement on our daily lives.

Feel free to join in to spread the word about all the advantages the metric system has versus our cumbersome U.S. customary units.

While not new, I found an interview where Rachel Maddow celebrated World Metrology Day back in 2010. You can view the seven minute clip here.

I hadn’t come across this before and was surprised to learn that several scientists with the National Institute of Standards were awarded Nobel Prizes for their work with time and temperatures during the past few years including: David J. Wineland (2012), John (Jan) L. Hall (2005) and William D. Phillips (1997) (More on them here.)

It’s not too early to start planning for next year

I don’t know that we’ll be in a better position to participate in World Metrology Day by the 140th anniversary (2015) but hopefully we will by the 150th anniversary, or sooner, if enough people in this country decide to do something about it.

Thanks,

Linda