In November, scientists and diplomats voted unanimously to redefine the kilogram. They decided the kilogram will no longer be based on a physical piece of metal, but on a math problem instead.

Metrology, the branch of science dedicated to measurement, has created better and better systems of measurement for the kilogram based on fundamental principles rather than arbitrary chunks of metal ...

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 ...

What does a kilogram weigh? Middle school science classes often teach that the unit is based on the weight of water—specifically a cube of water, a tenth of a meter on each side, at just above ...

The official object that defines the mass of a kilogram is a tiny, 139-year-old cylinder of platinum and iridium that resides in a triple-locked vault near Paris. Because it is so important, ...

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 ...

After 130 years, the kilogram has been redefined. The new standard is based on the fundamental laws of physics and is much more accurate. The dad joke answer to that question is, it weighs about one ...

Grams (g) and kilograms (kg) are used to describe measurements of mass. Grams are used for smaller or lighter items. 1,000 grams are equal to 1 kilogram. You can write it like this: 1,000 grams = 1 ...

More than a century ago, a small metal cylinder was forged in London and sent to a leafy suburb of Paris. The cylinder was about the size of a salt shaker and made of an alloy of platinum and iridium, ...

When you measure the mass of an object that is more than 1,000 grams, you should describe it in kilograms. Kilograms can be shortened to 'kg'. Here is a paper clip. It has a mass of 1 gram, which can ...