India joins the global initiative on World Metrology Day, which registers new SI units of 'kilogram' and other base units

NEW DELHI: With countries around the world saying goodbye to the original kilogram (kg) by introducing redefined (SI units) in the National Physics Laboratory of India (NPL), the country's national measurement body, also on Monday they adopted the new system and launched a campaign to raise awareness among users about how the new kilogram and three other base units will work in the country without affecting their daily work.

The new kilogram (unit of weight) and three new base units (ampere (electric current), Kelvin (temperature) and mol (quantity of substance like atoms)) will not be based on physical artifacts but on constants of nature '( quantum standards).

It means that your values ​​will never change and countries will not have to copy their internationally accepted prototypes. In any case, the change is not cause for concern, since scientists use the same mass of previous kg and, at the same time, scientifically redefine the new kg.

There are seven SI base units. While second (time), meter (longitude) and candela (unit of luminous intensity) have long been based on constants of nature (quantum standards), the redefined units of the remaining four were introduced globally on Monday. Metrologists from more than 60 countries, including India, agreed to the change in the General Conference on Weights and Measures in Versailles, France, in November last year.

When asked if existing instruments need immediate calibration in light of the change, DK Aswal, director of the NPL, said: No, we do not need that. The proposed changes in the definition of the unit have been designed to have no immediate consequences.

He told TOI, The length is already being measured in terms of speed of light. Time is also currently being measured using redefined units. For the mass, we will use the equilibrium of Kibble (electromechanical measuring instrument) of others (INM) until we build ours. .

On his involvement, Aswal said that he may not change anything drastically, but that it will matter when it comes to measurements of less than one kg. For example, measuring smaller diamonds or precious metals.

The change can be better understood from an example of kg. Currently, kg is defined as the weight of a small cylinder of polished platinum-iridium made by man, cast in 1879. It has been kept in the International Office of Weights and Measures in Sevres near Paris in France since 1889. It is called 'international prototype kg' (IPK). It is copied by countries around the world for use through instrument calibration.

However, this IPK has lost about 50 micrograms (approximately the mass of a tab) since it was created due to contamination or cleanliness. But, it is still used as a kg according to the above definition despite losing weight. Under the new scientific system, the kg of weight will always remain a kg, since it is not based on the physical artifact. The same principle applies to other units, ensuring constant value and universality.

In simple terms, a standard flour bag will contain as much flour as it always did in new definition kg, which means it will not change a bit forever.

The NPL, as its national responsibility, has prepared documents, recommending the incorporation of the changes in the textbooks and in the study plans of the metrology courses at IIT, NIT and other academic institutes.

Officials here said that redefined SI units would not change values ​​in real terms for everyday jobs. However, it will guarantee its long-term stability and universality and will help to obtain accurate data in all sectors, including the environment for measuring pollutants. All future measurement instruments will come with factoring in redefined units, they added.