“A read of the term here is literal:
‘One hundred steps’ seen in the interval
From boil to freeze
As we scale the degrees
In the temp’rature’s centigrade water-fall.”
The 17 April 2025 limerick again built on information I learned from Isaac Asimov’s 1959 book, Words of Science and the Histories Behind Them. This particular poem commemorated the Latin roots of the word “centigrade.”
“A read of the term here is literal…”
Many temperature scales exist and are useful in different contexts. Several are named for the scientists who devised them, such as Daniel Gabriel Fahrenheit; William Thomson, 1st Baron Kelvin; and Anders Celsius.
“One hundred steps’ seen in the interval /
From boil to freeze /
As we scale the degrees /
In the temp’rature’s centigrade water-fall.”
The Celsius scale was known first as the centigrade scale. A temperature scale is defined via two reference points. Anders Celsius proposed in 1742 that a new scale be defined, with water as the reference material: zero could be used for the boiling point and 100 for its melting point. He further proposed one hundred steps between them, using the term “centigrade” to denote this (“centum” means “one hundred” in Latin; “gradum” means “steps”).
The two references were ultimately reversed, and the scale was renamed in 1948 in Celsius’s honor. Thus, in our current experience, 0 °C now represents the temperature at which ice melts to form liquid water, and 100 °C represents the temperature at which liquid water boils to form steam.
The Celsius scale is closely related to the Kelvin scale: for instance, a difference of ten degrees Celsius would be equal to a difference of ten Kelvin. The Kelvin is the SI (International System of Units) unit of temperature, and its scale extends to absolute zero: 0 K, or -273.15 °C. Temperatures expressed in degrees Celsius can be easily converted to Kelvin by adding 273.15. (Because the Kelvin scale is absolute, SI convention states it does not use the “degree” sign or notation.)
Chemphasis 