When dealing with sometimes dusty metal from a cylinder in a vault outside Paris, as a global reference for modern mass, scientists update the definition of kilograms.
London: After years of treatment, a dusty metal cylinder in the vault outside Paris as a global reference for modern mass, scientists update the definition of kilograms.
Just as the redefinition of the second 1967 helped to facilitate global communications via GPS and the Internet, experts say that the change in kilograms is better for technology, retail and health – although it is unlikely to change far more fish.
The crown has been defined since 1889 with a glossy platinum-iridium piece in Paris. All modern mass measurements trace it – micrograms from pharmaceuticals to pounds apples and pears, as well as tons of steel or cement.
The problem is that the "international prototype pounds" does not always press the same. Even within its three glass candles, it gets dirty and dirty, and it affects the atmosphere. Sometimes it needs to be washed.
"We live in today's world," says Ian Robinson, a department of technology, materials and electrical science specializing in the UK's National Physical Laboratory, which contains impurities that can withstand the mass.
"So when you just get out of the vault, it's a bit dirty, but the whole cleaning or processing or massing method can change your mass so it may not be the best way to set the mass."
We need something established.
So, at the end of a week-long meeting at the Versailles Palace in Paris, the world's leading meta-interviewers at the International Press Office will vote on Friday to form an electronic congregation to measure the baseline of the new mass.
Just like a meter – when the length of the platinum-iridium beam, which is also held in Paris, is now defined at constant speed under light in vacuum, so the kilogram is defined by a small but unchanging basic value called Planck's standard.
The new definition uses a Kibble Balance called a device that uses a constant to measure the target mass using accurately measured electromagnetic force.
"In the current system, you have to relate small masses to large masses by subdivision. It is very difficult – and uncertainties are growing well, very quickly – Robinson said.
"One of the things that this (new) technology allows us to do is really measure the masses on any scale we want, and that's a big step forward."
He said it had lasted several years to fine-tune a new definition to ensure smooth transition.
But when the extra accuracy is good for researchers, Robinson said that the average consumer buys flour or bananas "there is no change".
(Reporting by Kate Kelland; drawing Kevin Liffey)