The kilogram, ampere, mole, and Kelvin are changing to stay the same

Not to brag, but the SI is at least one foot (see what I did there?) ahead of Imperial units.

What is mass? Baby don’t weigh me – revamping the metrology of mass

The metric system is due for a mass makeover, as scientists are preparing to redefine four basic units by the end of 2018 in an effort to provide accurate measurements at all scales.