2 Feb 2017

When is a kilo not a kilo?

From Jesse Mulligan, 1–4pm, 3:31 pm on 2 February 2017

This Way Up's Simon Morton discovers how the weight measurement we call the kilogram is changing.

The US national prototype kilogram standard mass, number K

The US national prototype kilogram standard mass, number K Photo: (Photo credited to US National Bureau of Standards, now National Institute of Standards and Technology (NIST)