I seem to recall in an old textbook or somewhere a system of measuring temperature called the “Rankine” scale. It was similar to the Kelvin system, where it started at absolute zero, but used Fahrenheit degrees, whereas Kelvin used Celsius degrees. Thus 0º F would be something like 459º on the Rankine scale. However, I’ve never seen it actually used anywhere. Typically, for most degree ranges outside the human experience, Celsius degrees are used (whether on the Celsius or Kelvin scales). Anyone familiar with this scale, and why it never caught on. Did we have a temperature scale glut?
I’ve used it, but rarely. Mostly, people who need to work with an absolute scale are technical people, who are most likely already using Celsius, so it doesn’t make sense to use Rankine. The few times I’ve used it were back-of-the-envelope calculations, where the starting and ending temperatures were in Fahrenheit, so it was (slightly) easier to switch to Rankine.
Arjuna34
I would have thought this temperature scale still had its adherents among US and British engineers? I came across it in college, but it was just a curiosity like slugs and poundals. We mostly stuck to SI.
I used it fairly often in thermodynamics and fluid dynamics classes. Of course, we also used slugs fairly often (and I will always remember that the sea-level density of air is 0.002377 slugs per cubic foot). This was within the past four years. I think engineers in the US still use English units fairly often.
Physicists, on the other hand, almost never use the old English units, and when they do, it’s usually either a textbook problem or something back-of-the-envelope where they don’t bother to convert. I’ve never seen Rankine used for anything in physics.
If you want to get really weird with your temperature scales, there’s also the Einstein scale, which is measured logarithmically so there’s no limit on how far below zero the numbers can go. I’ve never seen that one used, either, but it’s occasionally mentioned.
The reason you don’t see it too much in college is that college courses tend to favor SI units, whereas Rankine is British. Once you get into the world of engineering where many US mechanical engineers are partial to BIN units, you still find rare use of the absolute temperature scale, except by thermodynamicists, who constitute a small demographic even in the engineering world. Even a heat transfer analyst (a hat I very occasionally wear. Someone with more experience than I have in this area may wish to straighten me out a little bit.) is calculating a change in temperature, which is then added to or subtracted from the known temperatures, so it’s really not necessary to subtract 459.67 degrees to get Rankine units, only to add it back later on. Thermodynamicists, on the other hand, perform calculations where the total temperature is multiplied or divided in a function, so absolute units are needed.
On a side note, I’m noticing a trend in the semiconductor industry toward SI units.
I should add that fluid dynamicists would also be interested in absolute temperatures. It still comes down to a pretty small demographic using degrees Rankine.