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 ...

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 from around the world are gathering in France today to decide the fate of the kilogram. For nearly 130 years, the kilogram has been based on a lump of metal called the Big K, locked in a ...

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.

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 ...

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 ...

The kilogram may need to go on a diet. The international standard, a cylinder-shaped hunk of metal that defines the fundamental unit of mass, has gained tens of micrograms of mass from surface ...

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 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 ...

Scientists have changed the way the kilogram is defined. Currently, it is defined by the weight of a platinum-based ingot called "Le Grand K" which is locked away in a safe in Paris. On Friday, ...