The supreme arbiter of mass for humankind is a polished cylinder of platinum alloy just smaller than a golf ball. It was cast in London in 1879, unveiled a decade later in a ceremony in France, and ...

In a subterranean vault in a suburb of Paris lies a small, rarely seen metal cylinder known as Le Grand K. For 130 years, this golf-ball-sized hunk of 90% platinum and 10% iridium has served as the ...

When we measure the world, we measure it using base units like 'foot,' 'mile,' 'meter,' and 'second.' But who decides how big those units of measurement are? In the United States, those units are ...

The definition of a kilogram, a unit roughly equal to 2.2 pounds, has changed forever. Since 1889, the kilogram has been defined by a platinum-iridium alloy cylinder nicknamed Le Grand K, which is ...

After more than a century, the international prototype kilogram – a cylindrical chunk of metal stored in a French vault – doesn't weigh the same as its 40 replicas, distributed worldwide and used to ...

A kilo is a kilo is a kilo, right? Wrong. Monday marks World Metrology Day, and this year’s edition sees a big change in the way the kilogram unit is defined. In November last year, scientists and ...

Scientists and policy makers from around 60 nations voted unanimously Friday to redefine the kilogram. The decision at the General Conference on Weights and Measures in Versailles, France was greeted ...

The new kilogram has finally arrived. Updates to scientists’ system of measurement went into force May 20, redefining the kilogram and several other units in the metric system. The revamp does away ...

Add Yahoo as a preferred source to see more of our stories on Google. Le kilogramme est mort. Vive le kilogramme! The U.S. National Institute of Standards and Technology called this Friday a "turning ...

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 ...

The 'one kilogram to rule them all' was cast in platinum and iridium in 1879 and is kept in a triple-locked vault THE world says goodbye to the original kilogram on May 20, on World Metrology Day.