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Why the Metric System Doesn’t Scratch My Inch
At the Federal Standards Laboratory in France, 1,500 scientists toil away to make the world a more precise place. But once a year, they put on their party hats and weigh the platinum-iridium cylinder that defines the kilogram (kg). It’s a century-old artifact normally hidden away behind a heavily guarded safe outside Paris. The disturbing result is that it has actually lost weight, 50 micrograms (about a grain of salt if you’re counting, and those folks are counting for sure). When the surviving 80 cylinders from around the world are compared, it adds up to 10-7 uncertainty.
Having been properly indoctrinated to believe that the world of meters and liters was by far superior, or at least scientific, I was more than a little shocked to realize the International System of Units (abbreviated by the letters SI ) is still being tinkered with. So I had another look at the good old Imperial system, just for old time’s sake.
We could always resort to the tried and tested pound, or lb for short (from the Latin word libra, meaning scales). According to the Metric Treaty of 1893, 2.20462 pounds equals 1 kg. But that was amended, a year later, to 2.20462234 pounds equals 1 kg. Alas, it wasn’t until the 1950s that they finally got it right and set the pound to its modern measure: 1 lb = 0.45359237 kg. Pounds actually get pretty interesting depending on where you’re counting from. Historically, there have been Roman pounds, French pounds, Jersey pounds, London pounds, wool pounds, Scottish pounds and more. I think I’ll stick to my metric pounds, please.
OK, so the units for weight are a little weird. But what do you expect when you put 1,500 scientists in a room together with nothing to do but measure stuff? Maybe the unit for distance can go the mile (or if you prefer, 170.1078 x 10-15 light years).
The meter was originally defined as 1/40,000,000 of the Earth’s circumference (make sure to follow the meridian that cuts through France and Spain and forget that equatorial bulge). For a while, the meter was defined by the height of a similar lump of platinum like the one giving the kilogram so much trouble. So finally, Unit-arians struck paydirt when they defined the meter as the distance traveled by light in an absolute vacuum during 1/299,792,458 of a second. That’s nothing to shake a stick at – unless you’re using a yardstick. It’s a good thing we have a National Bureau of Standards. Effective July 1, 1959, 1 yard = 0.9144 meters. Argh!
I think we all just need to hold on a second. Except time is actually the single holdout when it comes to metrification. In everyday use, a second is 1/60th of a minute, a minute is 1/60th of an hour, an hour is 1/24th of a day, a day is 1/7th of a week, etc. It just goes on and on.
OK. Fine. I give up. Or at least I give up trying to go back and forth without a calculator. I suppose I don’t feel so bad knowing that even rocket scientists can’t get their units squared. In 1998, a Mars orbiter crashed because the navigation data was sent in English units and NASA expected metric ones.
Maybe this confusion could be avoided if we all just followed the same set of arbitrary measures. And the metrics have a keen advantage in terms of area (I know it’s hard to fathom2 = 3.34450944 square meters). Even the moon is metric. That leaves the United States, Liberia and Burma as the only nonmetric countries in the solar system.
