A poster for the new International System of Units


Don’t worry: it probably won’t affect you.

As a species, we’re redefining the system of measurement units used by billions of people across the world.

The proposed change, expected to be adopted by the General Conference on Weights and Measures (a big meeting of government delegates to deal with this kind of thing) in November 2018, will firmly base the International System of Units on the rules of nature.

This redefinition isn’t going to change any values, but rather restructure the system of units. Rather than deriving certain constants (such as Planck’s constant and Avogadro’s constant) from empirical measurements using the units, we will redefine the units based on fixed numerical values for those constants.

For example, the kilogram will be defined by Planck’s constant, rather than the hunk of platinum-iridium metal currently sitting in a basement near Paris. (I’m serious. Watch this video from Veritasium about this.)

I made a poster to commemorate the change, using the promotional files created by the BIPM’s task group for the promotion of the SI. (I hope they don’t mind.) It gives the new definitions as they’re expected to be in effect from 2018.

I doubt the Americans are going to want to put this up on a wall, so it’s laid out on A4 paper dimensions.

It’s free for use for instructional, educational, and promotional purposes! Download a PDF version here.