Eli5: why is the base SI unit of mass a kilogram, not a gram?

656 views

No other base units have a prefix, so why does mass?

In: 188

11 Answers

Anonymous 0 Comments

When the French were developing the metric system, they suggested the unit be called a grave (pronounced grav) being the mass of 1L of water (1000 cm^(3))

The French at this time being in the middle of a revolution against the rich notice that it sounded a lot like the word Graf, being a word for Duke or Earl, and they wanted to avoid affiliating with the nobility, so they changed the measurement to be the mass of 1mL of water (1 cm^(3)) and called it the gramme

They then noticed that it was inconvenient to use a mass unit so small, so they changed back to the 1L of water definition, but kept the name gramme for the base, and threw out the word grave in favor of the kilogramme.

And that’s why the kilogram is the base SI unit and not the gram. I had the exact same question when I learned the SI unites.

You are viewing 1 out of 11 answers, click here to view all answers.