The decision has been in the works for several years now (Photo via Associated Press)
I kind of live for news like this. Recently, scientists voted to change the definition of the kilogram along with the ampere, the Kelvin, and the mole. The decision was made at the General Conference on Weights and Measurements in Versailles, France.
So what exactly does this mean? The measurements will now be based on “fundamental constants of nature,” which are more precise than their current definitions. In other words, they’ll be defined in terms of physical constants. The kilogram will now be defined by the Planck Constant, h, while the ampere, Kelvin, and mole will be defined by the elementary electrical charge known as the Boltzmann constant and the Avogadro constant. The value of the Planck constant will be fixed at exactly 6.62607015 x 10 -34.
Originally, the kilogram was designed to equal the mass of a liter of water. Soon, this was represented by a cylinder, which was then adopted by other countries. This is known as Le Grand K, which is housed in Paris. Only a few people have access to this meaning others had to rely on imprecise measurements. Now, anyone with the know-how will be able to use the fixed value of the Planck constant to measure mass.
Though it sounds like an overnight change, it’s actually been in the works for quite some time. It’s a chance scientists are thrilled about, but it doesn’t mean a whole lot to most people. For instance, a kilogram of ground beef will still amount to the same number of hamburgers. Rather, the change benefits scientists helping them to make more accurate measurements. This also means the measurements will be universal.
“The SI redefinition is a landmark moment in scientific measurement,” says Jan-Theodoor Janssen, director of research at the UK’s National Physical Laboratory. “This will pave the way for far more accurate measurements and lays a more stable foundation for science.”
The new definitions will be put in place May 20, 2019.
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