Hy Tran examines a kilogram sample in a mass comparator at Sandia’s Primary Standards Laboratory. Photo by Randy Montoya

(Sandia Corp.: Albuquerque, New Mexico) -- The kilogram is losing weight and many international scientists, including some at Sandia National Laboratories, agree that it’s time to redefine it.

Scientists are hoping to redefine the kilogram by basing it on standards of universal constants rather than on an artifact standard.

The International Prototype Kilogram or “Le Grand K,” made in the 1880s, is a bar of platinum-iridium alloy kept in a vault near Paris.

“The idea is to replace the single master kilogram with something based on physical constants, rather than an artifact that could be damaged accidentally,” says mechanical engineer Hy Tran, a project leader at the Primary Standards Laboratory at Sandia.

Sandia is a National Nuclear Security Administration laboratory.

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