We measure stuff all the time—how long, how heavy, how hot, and so on—because we need to for things such as trade, health and knowledge. But making sure our measurements compare apples with apples has ...

The NIST-4 Kibble balance, an electromagnetic weighing machine that is used to measure Planck's constant, and in turn, redefine the kilogram. Jennifer Lauren Lee / NIST Locked in a vault that requires ...

Since 1889, human civilization has depended upon a magic rock. Known as Le Grand K, it sits under protective glass in St. Cloud, France. Humanity's magic rock is actually a chunk of metallic alloy ...

How much is a kilogram? 1,000 grams. 2.20462 pounds. Or 0.0685 slugs based on the old Imperial gravitational system. But where does this amount actually come from and how can everyone be sure they are ...

The official US kilogram — the physical prototype against which all weights in the United States are calibrated — cannot be touched by human hands except in rare circumstances. Sealed beneath a bell ...

When news breaks, you need to understand what actually matters. At Vox, our mission is to help you make sense of the world — and that work has never been more vital. But we can’t do it on our own. We ...

The U.S. National Institute of Standards and Technology called this Friday a “turning point for humanity,” even though the difference between this day and the day before weighs, theoretically, nothing ...

Physics is a funny thing. Despite dictating the behaviors and states of everything from atoms to stars, our interpretation of its effects are rooted in very human constructs. Meters, amperes and ...