Why is Rankine Measured in Degrees?

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SUMMARY

The Rankine scale (°R) is an absolute temperature scale based on the Fahrenheit scale, where the freezing point of water is defined as 491.67 °R. Unlike Kelvin, which is denoted without degrees, Rankine is traditionally associated with a degree symbol. Since 1967, Kelvin has been officially recognized without the degree symbol (°K), leading to confusion regarding the notation of Rankine. The discussion highlights the historical context of temperature scales and the evolution of their definitions.

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I know kelvin has no degrees because it is an absolute scale, but I've never seen rankine not be associated with a degree, yet it is also an absolute scale. Anyone know why this is?
 
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I think it should as well be °K because the degree basically refers to the step size which matters a lot. However, it simply doesn't make a difference. Most likely it's for historical reasons (which I don't know).
 
fresh_42 said:
I think it should as well be °K

it is just Kelvin, no degrees

since 1967, no longer written °K

that I also didn't know ... thought it has always just been just Kelvinlive and learn :smile:
 
Maylis said:
but I've never seen Rankine not be associated with a degree

hadn't even heard Rankine temp scale... must have been in very limited use

Another absolute temperature scale is the Rankine (°R) scale, once used by engineers in the United States and based on the Fahrenheit (°F) temperature scale, with the freezing point of water defined as 491.67 °R. A degree Rankine, like a degree Fahrenheit, is 5/9 of a kelvin or degree Celsius.
D
 
davenn said:
it is just Kelvin, no degrees
Yes, but I still think (meant as an opinion, not as an assumption) °K would be more accurate.

live and learn :smile:
Yes! And I've read about many other scales I've never heard of before, too. I always thought Kelvin, Celsius, Fahrenheit and Réaumur were all.

And I learned that Celsius was an upside down scale in its beginning, i.e. freezing at 100°C, evaporation at 0°C! It has been changed by Linné shortly after Celsius' death. And the Russian also used a turned scale in the 19th century: °D (Delisle).

And I learned that the triple point of water defines Kelvin. I've always wondered where the discrepancy between 273,15°C and 273,16°C comes from. I mistakenly thought it had something to do with the change of definition since my school days.
 
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