Thus, all mother kilograms will be more stable – Pages

A historic event – on the brink of a metrological revolution.

Then the vote at Versailles Friday can be described. Representatives from some 60 countries, including Sweden, are expected to adopt a new system for defining physical quantities. This includes the international unit of weight (kilogram).

It's huge and the result of a job that has been going on for decades, says Sten Bergstrand.

He is a researcher at Sveriges Riksmätplats, responsible for coordinating Swedish variants of the physical quantities of the International Dimensional System with the International Bureau for Measurement and Measurement of Weights (BIPM) in Paris.

We are terrified to be seen, but we think we are laying the foundations for global trade, "he said.

Important to accept

It may sound like a lot, but the facts and the trade are largely based on the fact that one meter is one meter, one kilogram is equivalent to one kilogram, and so on.

This may not be noticeable for gemstones, but for companies such as precious metals or the manufacturing industry, it is crucial.

Imagine that you are going to make a motor, but let someone else make the pistons that must exactly match the cylinders. Then you have to agree perfectly on the length of a millimeter, says Bergstrand.

At the end of the 19th century, a number of standardized measures were taken. In platinum and iridium alloy, a stick with two zippers was created and the other was determined exactly to one meter. Similarly, a cylinder was determined to be exactly one kilogram.

traceability

At the same time, several copies have been created for different countries. The Swedish national divorce is kept in a safe in the basement of the Rise in Borås research institute. So important is considered to be, because it's the basis for weighing everything in Sweden. And to know that everything is correct, there is also a traceability, a calibration chain that leads to majorities in Paris.

If you weigh a kilo of fruit at the grocery store, it's often a sticker on the scale. He says that it's calibrated in a wave lab, which in turn calibrated its scales in a measuring institute that calibrated its weights against ours, as we checked the kilot road in Paris .

But the system is vulnerable. What will happen if "urkilot" in Paris would be destroyed?

Over the past 130 years, the Swedish kilot has been compared three times in Paris. Differences have occurred over the years. The Swedish kilot weighs not exactly one kilo more, but 0.999999965 kilogram +/- 2.5 micrograms.

To cope with the problem, we have been working for years to get rid of old methods of weighing and measuring. Therefore, in the 1960s, he began measuring the SI unit for a second (second) using the fluctuations of the cesium atom. In 1983, "ureter" was replaced by the length of light moving under vacuum for 1/299 792 458 seconds.

logically

Now it's time again. On Friday, the historic decision should redefine SI units by weight (kilogram), current (amperes), temperature (kelvin) and amount of substance (in moles).

The starting point is that these devices will in the future be based on physical constants which, by definition, are always the same. In this way, the kilot will be defined on the basis of the Planck constant, which is a measure of momentum at the quantum level. Kilot as such will be realized with the help of a so-called Kibblevåg, an electromechanical instrument that measures the weight of an electrical article instead of the current balance weights.

In Sweden, we do not have this wave, but we will build one with the help of British colleagues.

For the uninitiated, everything is complicated and circumstantial. But he has his points, according to Bergstrand.

All measurements, including these, contain uncertainties. But the imagination of the new system is that everything is logically connected, "he said.

Because the system is achievable everywhere, it becomes less vulnerable. And since each constant is based on a frequency measurement, it will result in more precise measurements, because we can now measure frequencies up to the sixteenth decimal place.

The idea is that the new system will be used on May 20th of next year.