# Is the kilogram still consistent with the old definition?

My old understanding was that a gram is the amount of mass in a cubic centimeter of water.

But then I recently learned that the second was redefined to be some 9 billion cycles of a Caesium atom. Then from this the definition of a meter changed from 1 ten millionth the distance between the equator and north pole, to $1/299 792 458$ the amount of distance that light travels in a second. From this I would have assumed that now a hundredth of that meter would redefine the gram, which would then be multiplied by $1000$ to get the kilogram. But I read that instead the kilogram is some reference mass kept in a safe somewhere.

Are these definitions nevertheless consistent with each other or are we just doing away with the linkage between the centimeter and the gram via the water cube?

• Read about the history of the kilogram – MaxW Jul 14 '18 at 12:54
• You are really old school. Pt cylinders have been the reference standard since December 10, 1799. – MaxW Jul 14 '18 at 17:43

The kilogram is likely to be redifined in the near future as a function of the number of atoms of a sphere of ultrapure $$\ce{^{28}Si}$$, as per the answer to this Chemistry SE question. That means that the standard will be the Avogadro number, and the mass will be a derived unit.