Today, what is the standard unit of mass defined in?

Question

Is it with a specified volume of water at 4C or a standard platinum-iridium cylinder?

Thank you for answering.

Answer 1

Right now it's till the Pt-Ir bar, but a recent article suggests that the bar has been losing mass! Some scientists want to redefine mass in terms of so many carbon atoms. See

http://www.sciencedaily.com/releases/200...

Answer 2

It is a bit confusing, but it is -- still -- the platinum-iridium cylinder, but they (the metrologists) are trying very to change it to something more portable.

Answer 3

gram in metric

if u talk about volume with mass, then you're probably thinking about density instead of just mass