Your Weight Is About to Be Redefined
A physicist at the National Institute of Standards and Technology once said, “If somebody sneezed on [the] kilogram standard, all the weights in the world would be instantly wrong.”
He was referring to a cylinder, sometimes called Le Gran K, which is housed in a vault in Paris and handled like a priceless gem. The mass of anything measured in the world—you, your groceries, exoplanets, galaxies—traces to the mass of this 126-year-old platinum-iridium cylinder,* the so-called international prototype. Researchers in every field of science and engineering need to trust that they’re using the same reference point as every other scientist and engineer. No cylinder, no reference.
Le Gran K is the kilogram against which all kilograms are measured, and scientists do anything to avoid exposing it to dirty hands and dirty air—and especially to sneezes.
Every few decades, since the prototype’s been around, scientists have removed the cylinder, cleaned it with a solvent, washed it with steam, and scrutinized its mass. They verify that its six official copies, housed in the same vault, still match up exactly.
Three verifications, roughly 40 years apart, have occurred since 1889. In 1992, disaster struck: A comparison of the second and third measurements suggested either that the original had lost about 50 micrograms—around the mass of a grain of sand—or that the copies had gained that amount. Though miniscule, those measurements showed that “the kilogram is not stable,” says Peter Mohr, a physicist involved in an effort to redefine the basic units of measurement.
This is why many scientists decry the primacy of the cylinder as an outright embarrassment with the potential to wreak havoc on the practice of science. As the 2014 Norwegian film 1001 grams put it, “Man determines the definition of weight, but it’s equally important to understand what the definition of weight does to man.”
Fortunately, all this is about to change.
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I keep it in a box under my work bench, but if they need a new standard, I'd be happy to donate it.
....so I adjust my scale to the weight I want to be....hence no exercise or diets needed.........
