The World's Roundest Objects: Perfect Silicon Spheres.

Australian scientists are trying to create the world's roundest objects: perfect silicon spheres to define a kilogram:

Scientists will use the spheres to determine how many silicon atoms make up a kilogram, and this will be used as the new definition — bringing the kilogram into line with other base units such as the metre and the second, which are all defined by physical constants.

"It's really an atom-counting exercise … and we'll come up with a new definition of the kilogram based on atoms, rather than based on the thing in Paris," explained Walter Giardini, of Australia's National Measurement Institute.

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That thing in Paris is a solid platinum-iridium cylinder kept at the Bureau International des Poids et Mesures (BIPM), which mass is, by definition, exactly 1 kilogram.


International Prototype (Image Credit: BIPM)


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"mmmark" has gggood cccomments. American engineers have no troubles (except for NASA and its subcontractors maybe) working in all kinds of mixed units. I'm used to seeing pressures expressed in psi, Pascals, bar, inches of mercury, inches of water, atmosphere, etc. You deal with them all and it's no biggee.

As for the kilogram standard... I am in favor of anything that removes this from the custody of the French. There is no telling when they might get invaded again and lose control of the kg prototype, Think what could happen if that were to fall into the hands of the wrong people! Now who is going to invade Australia? The New Zealanders? not likely...
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Vandoo- Yes, Chris is either a fool, or he's simply joking, or he's trying to goad folks into posting the typical anti-USA comments. Most Americans use both metric and US standard measurements, and all scientists use metrics daily. There is no "contest" between them here in America.
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figures some American would be the first to rip this.
I am pretty sure your military uses the metric system and they are as "good American" as you can get!
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@ Gitai, I think thats an approximation, it's not considered good enough for high accuracy experiments where they work in sub micro-gram ranges.
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