Monday, 14 January 2013

Kilogram must on a diet

Changes in the international prototype of the basic unit of mass can ruin science experiments that are very accurate measurements needed.

Kilogram may need to diet, since the cylindrical piece of metal that defines the basic unit of weight "stout" for a few tens of milligrams due to external contamination, according to a study just published in the American magazine "Metrology", reports Fox News.

Because of this situation, any state that has a copy of this standard weight, or international prototype kilograms (MPC), has a slightly different definition of weight, which can spoil the scientific experiments that require very precise measurements.

The consequences, as studies indicate U.S. magazine, I felt in international trade cases and in the case of goods which are very strict traffic restrictions based on weight - such as radioactive materials.

However, the "surplus" could be removed without damage to the ICC using ozone and ultraviolet radiation, according to the January issue of "Metrology".

This cleaning technology could be widely adopted as a standard way to measure the basic unit maintains consistent.

According to Richard Davis, metrologists-consultant to the International Bureau of Weights and Measures in Paris, it is a practical technique that does not require too much money and investing, what is the potential for wide acceptance. But Davis was not involved in
the study, according to Fox News.

Kilo has become an international standard 1875th , and then made ​​cylindrical piece of ground or MPC. It consists of an alloy of platinum and iridium, height and diameter of 39 millimeters, which is kept at the International Bureau of Weights and Measures.

Official copies are available prototype of the kilogram as a national prototype, with Parisian kilogram, known as a kilogram, compared to about every 10 years.

In the eighties of the 19th century made ​​the 40 pounds of prototypes that were handed Metre Convention signatory countries. Even then, however, scientists found that the pound could be "put on weight" due to the deposition of dust and various other substances on its surface.

To reduce the risk of surface deposition, made ​​the MPC in the form of cylinders and put them in the laboratory with filtered air, constant temperature and pressure, but there was no way to completely avoid contamination, said British metrologist Peter Kampson the University of Newcastle. Cleaning is currently carried out by well-trained technicians erased cylinders antilops piece of leather soaked in alcohol.

However, as each country clean your MPK in a different way in a different time, prototypes do not significantly differ in weight.

Scientists want to get rid of defining long-term weight over the piece of metal, and Kampson believes that "the definition be changed in the next five to 10 years." According to him, one way would be to use an electromagnetic device that consistently produces the same amount of power that could then be calculated by weight.

The prototype kilogram "won" 50 micrograms in 100 years

By scientific definition, the error in the actual weight of the basic unit of mass is zero. However, in practice, it is said that two micrograms error.

The international prototype of the kilogram appears to have "won" about 50 micrograms in 100 years. The observed variation is the prototype has stimulated the search for a new definition of kilogram.

It is true that for any object in the universe (except as provided for in France), which had a mass of one kilogram of 100 years ago and that has not changed since then, now be considered to have a mass of more than 50 micrograms per kilogram.

This perspective eliminates the purposes of standard units of mass, because the standard does not need to change over time.

No comments:

Post a Comment