The Definition of a Kilogram Has Changed! Here is What it Means

Share

By definition, whatever the lump weighed was a kilogram, so if a chunk fell off, then the mass of all the matter in the universe, if measured by kilograms, would change.

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. Image: EPA Why Has The Grand K Been A Problem?

A mass etalon, a copy of the original "Grand K" rests under its double glass dome during the International General Conference of Weights and Measures.

Scientists now have the "Planck Constant" which looks like this - 6.62607004 × 10-34 m2 kg / s.

Taken in 1901, the official definition of exactly what was "the Kilogram is a unit of mass equal to the mass of the global prototype of the kilogram".

For instance, the International Prototype of the Kilogram (IPK), a cylinder of a platinum alloy stored at the BIPM in France whose stability required often inaccurate comparisons with identical copies, will be retired and replaced by the Planck constant, quantum physics' fundamental constant that is ubiquitously available.

It has been locked away in a vault at the Bureau's headquarters in France, and has just six official replicas. The objective behind this change is to create a constant way of measuring a kilogram.

The flawless kilogram, as also the copies, however showed slight changes over time.

More news: There was a hidden message in Deepika Padukone’s wedding dupatta
More news: Facebook's Top Brass Say They Knew Nothing About Definers. Don't Believe Them
More news: Drunk 'Irish' woman abuses airline crew after being refused wine

"We know from comparing the kilogram in Paris with all the copies of the kilogram that are all around the world that there are discrepancies between them and Le Grand K itself", Dr Stuart Davidson, head of mass spectrometry at the National Physical Laboratory in the United Kingdom told the BBC.

The overhaul will see new definitions applied to four of the seven base units of the SI, as well as all units derived from them.

"This is not acceptable from a scientific point of view".

Friday's vote has permanently redefined the kilogram and sent Le Grand K into retirement.

The bureau says these new methods of determining measurement standards will be a million times more stable than those based on the old methods. Conceptualised in 1975, the metrological instrument was named after its inventor, Bryan Kibble at the NPL.

The current kilogram mass exerts a specific amount of force in Earth's gravity. The new definition means that the weight of a kilogram no longer has to be compared to a block of platinum.

In a similar way, the SI unit for the ampere will now be based on the constant for the charge of the electron. This was because the machine measures both current and voltage, which generates power that is denoted in watts.

"Those units, those constants chosen now, include everything we know, everything we have always known and provide that springboard for us to go pursue those things that we don't know", said Jon Pratt of the US National Institute of Standards and Technology.

Share