How We're Redefining the kg
In 2018 the kg will be defined by Planck's constant, not a hunk of metal. Try a free book from Audible for 30 days http://ve42.co/audible Special thanks to the staff at NIST who made this possible:...
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What do I have to push, sub-basement? >>Woman: Sub-basement.[Buzzing safety alarm]I'm at the National Institute of Standards & Technology in Washington D.C.and I'm going to the sub-basement.It's getting dark down here.We're going to find out how they're going to redefine a kilogram.The kilogram is in trouble.Since 1799, it's been defined as the mass of a metal cylinder,in a locked vault in a basement in Paris.But over the last century, careful measurements of this international prototype kilogramand in-theory-identical national standards from around the world,have shown that their masses are diverging.The spread has grown to around 50 micrograms, or 50 parts per billion.And having a standard o...
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What do I have to push, sub-basement? >>Woman: Sub-basement.[Buzzing safety alarm]I'm at the National Institute of Standards & Technology in Washington D.C.and I'm going to the sub-basement.It's getting dark down here.We're going to find out how they're going to redefine a kilogram.The kilogram is in trouble.Since 1799, it's been defined as the mass of a metal cylinder,in a locked vault in a basement in Paris.But over the last century, careful measurements of this international prototype kilogramand in-theory-identical national standards from around the world,have shown that their masses are diverging.The spread has grown to around 50 micrograms, or 50 parts per billion.And having a standard o...
