The standard weight has increased

The standard kilogram weight needs to be "folded" after experts have identified it as a few dozen micrograms because of surface contamination.

The standard weight, abbreviated as the IPK , was heavier than it was when it was introduced by the International Metrology and Quality Organization in 1875.

Standard weighing pan is near Paris (France)

That's the conclusion of a study by a team of experts from the University of Newcastle, according to the Telegraph.

To determine the change in just a few of these micrograms, they used a visualization technique called X-ray spectroscopy and looked at the surface of the weight versions stored in the water.

In the 1880s, a total of about 40 scales were copied and given to countries that signed the World Metrology Agreement.

The results show that surfaces have been exposed to carbon-based and mercury-contaminated substances for more than a century.

Although the deviation is not high, it would be a real disaster when measuring materials such as radiation, according to Peter Cumpson of Newcastle University.

Cumpson's team also found that ultraviolet light and ozone could be used to break the link between carbon atoms on the surface of the scale, but no way to deal with mercury.