The gram is at least as strange. It used to be the si unit of mass, but that was changed to the kilogram. The kilogram standard , the IPK, is weight of a hunk of metal hidden away in a bunker, or one of it's sisters. There are proposals out for a standard that can be reproduced without the original but they have not materialized yet. Most of the kids I know understand grams, but only because the price of ounces is out of their reach.
For those who don't know, the IPK or as it is known as "BigK" or "Le Grand K" is the International Prototype Kilogram stored in a Paris basement vault.
Engineers aren't always so smart. The only reason the gram used to be the basic unit of mass and no longer is because it was too small to be used in everyday use. Can you imagine buying roast beef by the gram? Buying by the kilogram makes more sense. The only things sold by the gram are small items under a kilogram.
Once again, the masses are asses.
Here is the definition of the kilogram.
It is being defined in terms of Planck's constant. The platinum iridium cylinder in Paris is a dead issue.
The purpose of redefining the kilogram was so an actual object would not be needed.
BTW, there is no need for the Platinum iridium bar in Paris to define the meter anymore either. That is defined as how far light travels in 1/299792458 of a second.
There is the crusade in physics to NOT have any of the seven basic units defined by an object but by physical constants that would be recognized anywhere in the universe.
As surely as Pluto is no longer a planet, The International Committee for Weights and Measures (CIPM) has proposed revised definitions of the SI base units, for consideration at the 26th General Conference on Weights and Measures (CGPM). It is expected that the formal vote, scheduled for 16 November 2018, will be approved and that the new definitions will to come into force on 20 May 2019.
GO METRIC. Join the US Metric Association.