21–29 of 29 posts
Would it be possible to define the KG as the amount of copper wire, when arranged in a configuration (a coil?), that causes a magnetic field of a certain size when a specified current is applied?
A fabulously overwrought drama of no value. Similar to Tibetan rituals. Other standards are related to fundamental physical constants. Time for weight to do the same.
Dr. Emmett Brown: There's that word again; "heavy". Why are things so heavy in the future? Is there a problem with the earth's gravitational pull?
From, of course, Back To The Future (1985)
Editorialised title - actual title is "The Search for a More Perfect Kilogram". Wired should use your title though ("Everything is Getting Heavier") - it's a catchy title for an interesting article. Also the picture half-way down is totally a TARDIS.
It would be interesting to know what is the source of that error (I didn't find the speculation of out gassing to be particularly compelling, but I didn't recall them mentioning how the companion standards were built).
Interesting article. I was under the impression that the kilogram was defined as the mass of one liter of water, but that appears to just be an approximation now.
Editorialised title - actual title is "The Search for a More Perfect Kilogram". Wired should use your title though ("Everything is Getting Heavier") - it's a catchy title for an interesting article. Also the picture half-way down is totally a TARDIS.
The article did state that the 'secondary' versions of the kilogram were getting lighter with respect to the Grand K and it was up to 500 mG which is quite significant. It would be interesting to know what is the source of that error (I didn't find the speculation of out gassing to be particularly compelling, but I didn't recall them mentioning how the companion standards were built).
A fabulously overwrought drama of no value. Similar to Tibetan rituals. Other standards are related to fundamental physical constants. Time for weight to do the same.
The article makes it quite clear why it isn't possible to relate weight to fundamental physical constants yet: the constants that can be used for this haven't been measured precisely enough yet. Until they are, using a block of metal in a vault that has lost about half a speck of dust worth of matter in two hundred years is more exact. [edit: typo]
"Aside from a yearly ceremonial peek inside its vault, which can be unlocked only with three keys held by three different officials, the prototype goes unmolested for decades. Yet every 40 years or so, protocol requires that it be washed with alcohol, dried with a chamois cloth, given a steam bath, allowed to air dry, and then weighed against the freshly scrubbed national standards, all transported to France."
Sounds sensible and reliable. No issue with corrosion, infiltration of gasses or lint I guess. And what about the other standards? Who knows which is changing?
"Steiner argues, the watt balance, with its Planck constant, is “a better realization,” because his system is self-contained and replicable, whereas the Avogadro project spans several continents and relies on a single artifact. "
A non-reproducible result is not science. It doesn't matter how many zeroes are involved; its not actually a verifiable fact if there's only one experiment, right?
A fabulously overwrought drama of no value. Similar to Tibetan rituals. Other standards are related to fundamental physical constants. Time for weight to do the same.
Next time read the article before posting.