Why Do These Even Exist

Devil: "My child will use Kelvin in analysis" versus Jesus blessing us with Rankine, Rømer, and Réaumur scales. The unholy trinity of temperature scales nobody asked for! While Kelvin actually serves a purpose in thermodynamics (absolute zero at 0 K, no negative temperatures, makes equations cleaner), these other three are like that drawer in your kitchen filled with gadgets you've never used.

Rankine is basically Kelvin's American cousin—it uses Fahrenheit-sized degrees but starts at absolute zero. Rømer was an early attempt from 1701 where water freezes at 7.5° (because why not?). Réaumur sets water's boiling point at 80° instead of 100°. These scales exist purely to torture engineering students who stumble upon old European scientific papers and have to convert everything back to something remotely usable.

Fun fact: There are actually even MORE obscure temperature scales like Newton, Delisle, and Wedgwood. Scientists really went wild inventing these things before everyone agreed to just stick with Celsius and Kelvin.