The Definition of a Kilogram Has Changed. Here`s Why.
(World News Science)

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 meter length is the same as yours. Attempts have been made to define the units of measurement over the years. But today-International Metrology Day -sees the complete revision of those standards come into play. You won´t notice anything-you will not be heavier or lighter than yesterday-because the transition has been made to be seamless. Just the definitions of the seven base units of the SI (Système International d`Unités, or the...