Look inside a lab! Today, we’re stepping into a special space for national metrology institutes around the world. The NIST-4 Kibble balance provides the definition of mass for the United States. It’s basing its measurements on the Planck constant that was given a fixed value as part of the redefinition of the kilogram in 2019. But not every country around the world can afford to house that kind of massive instrument. That’s why we have a shrunken version, which our researchers are working to mak