Did you know that a kilo now weighs less than it used to?

A small cylinder of titanium alloy known as Le Grand K has set the standard since 1889.

Every set of scales in the world has been calibrated against it, even those weighing in pounds and ounces.

It's so important to the global economy that three key-holders are needed to unlock the vault where the benchmark unit is stored.

However, it seems Le Grand K has a weight-loss problem.

Even thought he unit has only been removed from its case fgour times in its lifetime, it has lost atoms and therefore mass. So Le Grand K is now a little less than a 'K'.

Now, the weight it has lost would weigh about the same as an eyelash – just 20 billionths of a gram. But it's enough to make scientists wonder whether it can be rightfully used as the benchmark for the kilo.

Scientists from more than 60 countries will vote on Friday on whether a lump of metal held in a Parisian vault should continue to be the definition of a kilogram. 

Hence a global effort to devise a more accurate, immutable definition of a kilogram that is no longer dependent on a physical object.

According to Sky News, they are playing around with something called a Kibble Balance, named after the British physicist who first conceptualised it, to express the mass of a kilogram in terms of the amount of upward electromagnetic force is needed to balance the downward drag of gravity. Then with some heavy-duty maths, they relate that to a fundamental physical law of nature.

By taking the answer – a number called Planck's Constant - they can reverse the process and calibrate scales with unprecedented accuracy. Ian Robinson, a fellow at NPL, has been leading the work. He says labs around the world will be able to have a kibble balance, liberating the definition of a kilogram from its physical and geographical ties. "You are not reliant on any one object anymore," he said. "Effectively our mass scale is spread out and everyone can contribute. I see it as egalitarian - a form of democracy for mass."

Other important standard units have already been updated.

The metre is no longer defined by a rod of metal, but by the distance light travels in a set, and very small, fraction of a second. And a second is no longer defined by a fraction of the time it takes for the Earth to complete one rotation, which scientists now know varies, but by vibrations in a caesium atom.Michael de Podesta, a principle research scientist at NPL, said the public will not notice any difference when grocery shopping. "But it means people like me won't worry about the kilogram losing weight," he said."It will make it future-proof.

9 comments

Ahah, I knew it! The quantites in those packets I buy is getting less. They are losing atoms, we need bigger atoms!

The weight of an eyelash may not seem like much, but 20 billionths of a gram is important if one is trying to lose wight! :-)

oh good, i'm lighter than I think ;) 

The Kibble won't do, because gravity ain't constant as it varies according to how far we are from our sun (and other planets) and from our moon, as they all have counter gravitational forces on us.

No wonder people are getting heavier.

Funny.....

The Greeks measured weight by using grains. They measured length by using  body parts, now that was tricky since every member, haha could be a different size. Anyway it worked well.

i am having a laughing fit at these responses ..  hope i can lose a few eyelashes!

!! !!!

this doesnt surprise me at all,   lol, nothing is what it seems,   

9 comments



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