The concept of a kilogram, it would seem, does not carry anything new. After all, we are faced with this unit of measurement every day. 1000 grams is known to all. But do you really know everything about the kilogram?
What is a kilogram?
Obviously, the kilogram is a unit of mass. But not just a unit. The kilogram is registered in the International System of Units (SI) as one of the seven basic units corresponding to the seven basic concepts of measuring space along with the meter (length), second (time), ampere (electric current), kelvin (thermodynamic temperature), mole (amount of substance) and candela (light intensity).
The scientific definition of what a kilogram is was adopted in 1901 by the III General Conference on Weights and Measures. It happened in Paris.
Kilogram is a unit of mass equal to the mass of the international prototype of the kilogram.
This is the international scientific definition, adopted at the beginning of the 20th century and valid at the present time.
Where can I find the international standard of the kilogram?
InternationalThe standard is kept at the International Bureau of Weights and Measures in Sevres, near Paris. It looks like a platinum-iridium cylinder with the same diameter and height, which are 39.17 millimeters. There is more platinum in the alloy from which the kilogram standard is made - as much as 90%, while the addition of iridium is only 10%.
So the ideal kilogram exists and can be touched?
It would seem that there is a kilogram standard, that is, an ideal kilogram, once and for all fixed and unchanged. Unfortunately, that's just how it seems. Over time, the standard gives differences in mass compared to its original weight in 1889, when it was decided to release it on the basis of the Meter Convention of 1875. This is due to the fact that the metals from which it is made are exposed to the environment over time. The weight of the reference changes, albeit very slowly.
So in 2005 it was decided to redefine the kilogram. Now it should be based not on a tangible concrete quantity, but on a fundamental physical property. However, it was not until 2011 that the scientific community came to a decision on which quantity should be used to define the kilogram, and began work on redefining the kilogram and measures and quantities based on it, which should be completed in 2018.
To touch the kilogram standard is also impossible. It is stored under special conditions to minimize external influences that affect its change.mass, and is withdrawn only for verification of its copies. The last verification took place in 2014.
