“The SI units, redefined today:
No longer linked to objects in a vault,
But rather fundamental constants’ slate,
To minimize experimental fault.
The kilogram on Planck will now rely;
The kelvin will use Boltzmann to define
A temp’rature precisely and thereby
Consolidate discussions and designs.
Five other units likewise are recast–
Candela, second, meter, mole, ampere–
From genesis in revolution past
To standards metric by which STEM coheres.
With h, k, c, et al., assign true north;
Compare to ever-fixèd marks, henceforth.”
This sonnet, written for World Metrology Day in 2019, provides a useful transition from the April 2019 Limerick Project essays back into my general goals with this website. Moving forward, I will still aim to post twice a week, and when the substance of a post is a single poem “translation,” I will still aim for 280 words or fewer. Since this particular poem was spread over multiple Twitter posts, I’ll give myself 560 words as a maximum for the following discussion.
“The SI units, redefined today: / No longer linked to objects in a vault, / But rather fundamental constants’ slate, / To minimize experimental fault.”
Metrology is the science of measurement. World Metrology Day is May 20 and celebrates the anniversary of the definition of the meter as a standardized unit of measurement: one on which the world could agree for purposes of scientific and commercial collaboration. This occurred at the Metre Convention in Paris on May 20, 1875. World Metrology Day in 2019 marked the redefinition of the metric system, or the International System of Units (denoted typically as “SI units,” given the French translation of the name: Le Système International), in terms of constants of nature. Previously formulated in a variety of ways, these important units were redefined to rely on such quantities as the speed of light (abbreviated as c in scientific parlance) that are unchanging and universally known. This redefinition will allow ever more precise communication and collaboration within the scientific community.
“The kilogram on Planck will now rely; / The kelvin will use Boltzmann to define / A temp’rature precisely and thereby / Consolidate discussions and designs.”
The SI unit of mass is the kilogram. Previously defined by calibration against a specific physical object, one which had been kept in a locked vault, this unit was redefined in terms of Planck’s constant (h). The SI unit of temperature is the kelvin. While its previous definition had not relied on a physical object in the same way that the kilogram had, the redefinition linked the kelvin directly to Boltzmann’s constant (k). Both redefinitions will enable greater cohesion in scientific communication regarding experimental designs and results, as common reference points worldwide.
“Five other units likewise are recast– /
Candela, second, meter, mole, ampere– ”
Scientists use seven fundamental SI units in total: kilogram (mass), kelvin (temperature), meter (length), candela (luminous intensity), second (time), mole (amount), and ampere (electric current). With the redefinition presented in 2019, all seven now depend on fundamental constants of nature for their definitions.
“From genesis in revolution past /
To standards metric by which STEM coheres.”
The metric system was initially devised in the midst of the French Revolution (this is one of those brief statements present in introductory science textbooks that always seems worth an entire seminar course in itself). The same system now provides a coherent reference for scientists worldwide.
“With h, k, c, et al., assign true north; /
Compare to ever-fixèd marks, henceforth.”
The closing couplet of this sonnet denotes a few of the fundamental constants of interest to this redefinition (h, k, and c, noted above). These last lines also allude poetically to constants as they are defined in other disciplines. Finding true north, in geology, provides an absolute measure of directionality. In literature, Shakespeare describes steadfast love as an “ever-fixèd mark” in a famous phrase from his Sonnet 116. It was this last link that provided the inspiration for this particular exercise; I have always been intrigued by the centrality of “the meter” to science and poetry, in such different ways, and the focus on “constants” in different contexts was another fun theme to explore. Moreover, it was an interesting challenge to adhere to the rules on format and rhyme for an English sonnet, after so many weeks of limericks.