The kilogram is changing - not in a way you might think

In 1889, a platinum-iridium cylinder was made - a cylinder which would become precious to modern times and serve as the global standard for weighing. Its name: the kilogram.

The kilogram is currently stored in a strong room in Sevres, near Paris, France.



Every forty years it is withdrawn - but only so it can be compared to replica kilos, situated in every country which has adopted the metric system.

However, shockingly, the kilogram has been losing weight over time without any known reason. This has prompted scientists to think of a new measure, reports the Guardian. Here is what we know.

What is changing?

The kilogram is currently the only standard measurement unit, known as a SI, to be based on a physical artefact.

Air pollution is set to be the major threat to the current kilogram - despite it being stored in filtered laboratory air at constant temperature.

Dr Giovanni Mana, a researcher from the National Institute for Metrology Research, said in 2015, “'The absence of technologies to redefine the kilogram is the biggest impediment to a redefinition of the whole system of measurement units, which is expected to deliver even more solid foundations and reliability to precision measurements and to set the stage for further innovations in technology and science.”

As a result, a new system is being devised that involves using Planck’s constant.

It has taken scientists time to come up with a solution - as no one has been able to measure measure Planck’s constant precisely enough to improve on the sacred platinum-indium.

This month all is changing as multiple teams submit their results for computer analysis.

What this will mean

Our historical kilogram will be replaced by a more reliable definition. This will be based on our current kilogram which means scales and weights can be calibrated and verified as normal.

These weights will be internationally standardised - in effect making no different to Marsden.

For a full history of the kilogram as a unit of measure, click here to read the story from the National Institute of Standards and Technology.

You can find out more about the changes needed for the kilogram to stay current, here. Read more about the history of weighing in this blog post (translation required).

For more information on these changes - and any weighing scales in our range - you can contact Marsden on 01709 364296 or contact us here.

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