Take a good look at it. Because very soon, this 129-year-old standard for the kilogram will change. On Friday, scientists from around the world met at the General Conference on Weights and ...

That's most of the job of the metrologists, and why it's taken so long to replace the "magic rock" of the standard kilogram. Physicists have known that the standard kilogram was suboptimal for ...

But in one way or another, every single scale on the planet is connected to the international kilogram standard. While measuring flour in your kitchen will remain the same, the new standard makes ...

This now defines the SI unit, mole, used largely in chemistry. What of the Big K—the standard kilogram? Today it becomes an object of great historical significance that can be weighed and its ...

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 ...

Since 1889, the year the Eiffel Tower opened, that cylinder has been the standard against which every other kilogram on the planet has been judged. But that's creating problems. According to ...

If the washing protocol makes it into labs around the world, it could help with the problem of drifting masses – at least until a different standard kilogram is developed, one that relies on a ...

Instead, the kilogram is the last metric standard still bound to a human artifact. That artifact is the Kilogram—a two-inch-wide, 90-percent platinum, 10-percent iridium cylinder in Paris.

Contaminants have made the standard kilogram weigh slightly more than it originally did, but a careful cleaning method may slim it down. Sophie Bushwick reports How do you define one kilogram?

Friday, in a small conference center just steps from the Palace of Versailles, several dozen nations voted to overthrow Le Grand K and to redefine the kilogram and three other standard units of ...