The kilogram has the dubious distinction of being the only SI unit still based on a physical object; specifically, a metal cylinder kept in a vault in France. Plans are well underway to redefine the ...

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 ...

Deep underneath the Parisian suburb of Saint-Cloud, in a vault that can only be opened by three people wielding three different keys, there lies a hunk of metal that is so crucial to the world of ...

On the morning of Friday, November 16, scientists and diplomats crammed into an auditorium in Versailles, a stone’s throw from the Sun King’s gilded chateau. Patrick Abbott, an American physicist, had ...

Researchers at the National Institute of Standards and Technology (NIST) have made their most precise determination yet of Planck’s constant. This will let NIST redefine the kilogram, the official ...

The remarkable thing about our universe is that it’s possible to explore at least some of its inner workings with very simple tools. Gravity is one example, to which [Galileo]’s inclined planes and ...

A high-tech version of an old-fashioned balance scale at the National Institute of Standards and Technology (NIST) has just brought scientists a critical step closer toward a new and improved ...

There are many well-known physical constants, but it always interests us when someone can approximately measure them using equipment you probably have. We could pretend it is because we want to help ...

A high-tech version of a balance scale has just brought scientists a critical step closer toward a new and improved definition of the kilogram. The scale, called the NIST-4 watt balance, has conducted ...