“To celebrate day metrologic /
With global theme, STEM-philosophic, /
This May marks attention /
To Metre Convention /
As sesquicentennial topic!”
I’ll go slightly out of order with revisiting this particular poem, so that I can wind down NaPoWriMo2025 as I formally end my Spring 2026 semester next week. This poem was posted on Bluesky to celebrate World Metrology Day 2025.
“To celebrate day metrologic /
With global theme, STEM-philosophic…”
World Metrology Day is celebrated on May 20 each year; it celebrates the date on which the International System of Units (the metric system) was adopted in 1875. (The phrase “SI units” is often used as a shorthand, given the system’s name in the French language: “Système international d’unités.”) This was a banner day in the history of science; it marked a shift toward standardized, universal communication, or a “global theme, STEM-philosophic.”
“This May marks attention /
To Metre Convention /
As sesquicentennial topic!”
In 2025 specifically, the World Metrology Day celebrations were particularly festive, as it was the 150th anniversary (or the sesquicentennial) of the original Metre Convention in Paris.
The metric system had been proposed by France in 1799. The meter was first defined based on measurements of the Earth, and the kilogram was first defined based on a certain amount of water (these units represented far more egalitarian measurements than, for instance, a king’s foot). In 1799, France defined the units in relation to specific prototypes that were then housed in the National Archives. At 1875’s Metre Convention, several such standards were then distributed internationally.
The metric system has been adjusted in the years since. In 2019, famously, the seven base SI units were redefined in terms of the fundamental constants of nature, so that their values no longer hinge on physical objects.
(Metrology is a subject that tends to be highly condensed in a science course; we focus more on using and interconverting a few specific types of units than the history of measurement itself. James Vincent’s outstanding 2022 book, Beyond Measure, recounts several fascinating stories.)
Chemphasis 