SCIENCE

Scientists Finally Agreed On How Much A Kilogram Weighs

Scientists finally agree on the weight of a kilogram, and that's good news for modern technology, electronics and, yes, your smartphone

Oct 22, 2015 at 2:30 PM ET

Kilograms are extremely important. There are only seven units of measure that are truly essential to modern science and technology: meters (to measure length), kilograms (mass), seconds (time), amperes (current), kelvin (temperature), candela (luminosity) and mole (particles). From these units, scientists can derive any other unit. Heat capacity, for instance, is defined as joules per kelvin; joules are measured in meters, kilograms and seconds.

But what if we lost the kilogram? Confusion over the exact definition of a kilogram would throw off countless calculations—messing with microchips and ruining electronics that demand precision. That almost happened, but science came to the rescue. Here’s how we saved the kilogram, and why it matters: