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US Objects To the Kilogram
Velcroman1 writes "For 130 years, the kilogram has weighed precisely one kilogram. Hasn't it? The US government isn't so sure. The precise weight of the kilogram is based on a platinum-iridium cylinder manufactured 130 years ago; it's kept in a vault in France at the International Bureau of Weights and Measures. Forty of the units were manufactured at the time, to standardize the measure of weight. But due to material degradation and the effects of quantum physics, the weight of those blocks has changed over time. That's right, the kilogram no longer weighs 1 kilogram, according to the National Institute of Standards and Technology. And it's time to move to a different standard anyway. A proposed revision would remove the final connection to that physical bit of matter, said Ambler Thompson, a NIST scientist involved in the international effort. 'We get rid of the last artifact.'"
Last I heard, nobody had come up with a way to define mass without referring to an artifact. It seems easy but they all turn out to be circular.
Because this prototypical kilogram is what the definition of the pound is currently based on.
seriously, this is pretty old. physicists working in metrology have been working to redefine the kilogram for at least the last few decades
"For I am a Bear of Very Little Brain, and Long Words Bother Me"
The US cares that much why? Its only a trade matter, as we still use primitave imperial measurements. Maybe if we had switched to metric like they had told us we were going to every year in grade school this would be a big deal, but right now, who cares?
Because prices, taxes, tariffs, etc. care about pounds and kilograms. We still have a department of weights and measures, and they still do extremely important work. The fact that you don't ever notice any problems means they're doing their jobs.
Funnily enough I never ever think of a kilogram as the weight of some standard weight in a vault somewhere. The only way I ever think about the kilogram is the weight of one liter of water. Also comes in handy when I'm calculating how much liquids I can afford to buy when shopping groceries, given that I often go to the store on foot for the exercise and have to make sure I can manage the haul back.
So, um, does this all really matter? In practice, that is.
.: Max Romantschuk
The US was one of the original signatories to the treaty that defined the meter and started the BIPM which lead to the SI.
All US weights and measures, no matter what standard they are on, come from the National Bureau of Standards which standardized on the metric system, as has the USGS (since the early 19th century).
THe NBS has standard meter and kilograms that are copies of the originals kept in Paris, so the US has a valid reason to wonder about the new kilogram definition.
Very clever, Mr. Wittgenstein. Unfortunately shortly after you died we defined the meter in terms of the speed light travels in a certain amount of time, and abandoned the Paris standard meter. So one thing can be said for sure: the Paris standard meter is definitely *NOT* one meter long."
> ...we still insist on using the pound over the kilogram.
But we don't. The metric system has been legal for trade in the USA since 1866 and the official customary units have been based on it for almost as long. In 1975 it was official adopted by the Federal government for its use and in 1985 it was identified as the "preferred" system for trade. Most goods are labeled in both metric and customary units. It's just that, unlike other countries, the USA has not outlawed the use of customary units as we tend to prefer freedom of choice.
Warning: this article may contain humor, sarcasm, parody, and perhaps even irony. Read at your own risk.
Oddly enough, back in about 1780, the US was desperate to switch to the new metric standard that was being developed by France.
The reason why the US didn't go for it was the definition of the metre. Benjamin Franklin, who was a pretty good scientist when he wasn't being distracted by all this political nonsense, was unhappy with the French definition, which was a certain ratio of the Earth's circumference. The trouble with this is that not only is it practically unmeasurable, but it's not even a knowable value, as it changes depending on what you consider to be the Earth's surface. Franklin was aware that industry can always use as much precision as it can get. Events bore him out as the first metre artifact made turned out to be out by 0.2mm.
Instead he advocated an alternate definition based on the swing of a pendulum of a fixed period. This was a knowable value; it could be theoretically calculated to as much precision as your definition of the second. As the second was at the time was based on the length of the average solar day it could be determined as precisely as you could build your telescopes, it was a much more useful definition.
Unfortunately for complicated political reasons France was unwilling to go with this (possibly because their arch enemies, the British, were also considering a pendulum-based definition), so Franklin decided to stay with home-grown units rather than adopting the new metric system.
So if Franklin had been just a little bit more convincing when addressing the committees in Paris, the US might have been one of the driving forces of metricisation, and maybe my web browser would have the word 'metre' in its spellchecker dictionary.
Are you saying a NIST article is more accurate than a Fox article? Who would have thunk it