Scientists set to change definition of the kilogram

The master kilogram sealed in a jar and stored in a safe in Paris no longer weighs the same as this

"If we stay where we are, and someone did accidentally drop the kilogram or if there was a contamination that we couldn't control, then the whole system has got no head", said Barry Inglis, a scientist from Australia.

The kilogram will now be defined by the Planck Constant, while the ampere, kelvin and mole will be tied to the elementary electrical charge, the Boltzmann constant and the Avogadro constant, respectively. The conference is hosted by the International Bureau of Weights and Measures.

Accurate measurement is critical in many areas of the world today, such as in drug development, nanotechnology and engineering and is among reasons the Le Grand K rule is being changed. Yet, despite its heavy security, the cylinder has begun to wear away, causing slight inaccuracies in the way we define and measure a kilogram.

The reason for the change to the International System of Measurement (SI) units was that over time the prototype lost atoms and therefore mass because it is "susceptible to damage and environmental factors", according to the National Physical Laboratory (NPL), which houses Kilo 18, Britain's copy of Le Grand K.

The redefined kilo is expected to allow for more accurate measurements of very, very small or very, very large masses and help usher in innovations in science, industry, climate study and other fields.

The Grand K and its six official copies, kept together in the same safe on the outskirts of Paris and collectively known as the "heir and the spares", will be retired but not forgotten.

"The change brings our best scientific understanding of the natural world directly into our daily lives, and gives us access to a definition of the mass unit which is available to everyone with the will and the skill to perform the experiments", Canada's chief metrologist, Alan Steele, told NBC News MACH in an email in advance of the vote. The new definitions will be effective on May 20, 2019, World Metrology Day, which celebrates the establishment of the SI, or metric system, in 1875. It will be replaced by the Planck constant - the fundamental constant of quantum physics. The new definition of a kelvin promises advantages for scientists needing to make very precise measurements.

The Planck constant is, in turn, measured using an instrument known as the Kibble balance, first developed at NPL by the late physicist Bryan Kibble. Along with redefining a kilogram, other base SI units were also redefined.

In 2013, scientists discovered that the kilogram Prototype had gained tens of micrograms of mass from surface contamination.

After about 130 years, the definition of Kilogram unit has finally seen a massive change.

Unlike the old physical measurement, the new "electric kilo" formula can not accumulate particles of dust and pollution, decay over a period of time time, or be dropped and damaged.

Related:

Comments


Other news