The way we define kilograms, metres and seconds changes today
- Written by David Brynn Hibbert, Emeritus Professor of Analytical Chemistry, UNSW
A new standard defines the kilogram from today.Shutterstock/Piotr Wytrazek 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 been a challenge: how to know if my kilogram weight or...





