The kuub
Part of my units pages
We can avoid redundant metric units like litres by sticking with SI units like cubic metres. This keeps our units coherent, which simplifies calculations.
However, named units can still be useful, for a couple of reasons. Firstly, if we order a “700ml” bottle of water, we can be confident that we’ll receive 700 thousands of a litre, AKA 0.7l. In contrast, an order for a “700µm³” bottle might be misinterpreted, causing problems even for those who use the unit correctly (since the other party could misunderstand).
The other problem is that the phrase “cubic metre” is verbally cumbersome, which is a burden on its own; but also leads to awful abbreviations like “cc” for cubic centimetre (a centi-centi what‽).
These problems can be avoided if we name a derived unit for the cubic metre. Some non-English languages already have this, for example the “stere” or the “kuub”. The former might evoke a connection to steradians, but that’s quite a niche benefit. I think the name “kuub” has more intuitive appeal.
Symbolising the Kuub
We can’t symbolise kuub with a “k” or a “c”, since those clash with “kilo” and “centi”. One obvious symbol would be a cube, which we can draw isometrically as a ‘hexagon with spokes’. The closest Unicode I can find for this is Ⓨ (the letter Y inside a circle), so these quantities would be 3µⓎ and 3cⓎ.
Alternatively, we could use a specialised notation for space/time units.