Why We Learn Reaumur Temperature Scale in High School Physics

[bagasme]

Hi,

In high school physics I learned how to convert between celsius, Fahrenheit, Kelvin, and Reaumur scale of temperature. While the first three scales are highly used, why do we learn the fourth scale (Reaumur) when there aren't any practical use of it? Just for formality?

Bagas

 

[weirdoguy]

why do we learn the fourth scale

We do? I did not learn about it, no one ever even wanted me to know how to convert between Fahrenheit and Celsius. I guess it depends on the country.

 

[anorlunda]

The answer may be that it is needed to understand some historical literature. Do you come from
a Eastern Europe or Russian background? Are you close to cheese making factories?

https://en.wikipedia.org/wiki/Réaumur_scale
The Réaumur scale was used widely in Europe, particularly in France, Germany and Russia, and was referenced in the works of Dostoyevsky, Flaubert, Tolstoy, and Nabokov.[4][5][6] For example, at the beginning of Book X of The Brothers Karamazov, the narrator says, "We had eleven degrees of frost", i.e. −11°Ré, equivalent to 7°F or −14°C.[7] By the 1790s, France had chosen the Celsius scale as part of the metric system, rather than the Réaumur measurement,[2] but it was used commonly in some parts of Europe until at least the mid-19th century,[8] and in parts of Russia until the early 20th. Its main modern uses are in some Italian and Swiss factories for measuring milk temperature during cheese production,[9] and in the Netherlands for measuring temperature when cooking sugar syrup for desserts and sweets.

 

[Vanadium 50]

You mean your teachers taught you something that wasn't immediately useful? How dare they! The fiends!

 

[bagasme]

The answer may be that it is needed to understand some historical literature. Do you come from
a Eastern Europe or Russian background? Are you close to cheese making factories?

no.

 

[Ibix]

As Vanadium 50 points out, knowledge for its own sake is never a bad thing. But temperature scales are interesting because, although there's an absolute zero, Celsius and Fahrenheit don't use it. So the transform between them is an example of the most general 1d linear transform - both an offset and a scaling. So I'd say that gaining experience with these transforms is generally useful, even if some of the scales are somewhat esoteric. I have to admit that I didn't even know the name of the temperature scale with symbol R - I only knew of it because I had an old graphing calculator that could convert to it.

 

[sophiecentaur]

You mean your teachers taught you something that wasn't immediately useful? How dare they! The fiends!

I resented the fact that I was strongly encouraged / forced to learn Latin at school. But I still manage to carpe most diems and I still believe that in absentia lucid, Tenebrae vicuna.
Knowledge is the bicycle repair kit that you only use when you actually need it but still keep it handy.

 

[davenn]

, and Reaumur scale of temperature.

Never heard of it till you mentioned it, and I have been on this ball of rock longer than I care to remember

 

[Charles Link]

a google (of Rankine) shows there are 3 temperature scales with the letter $R$. The third one is Romer.
See https://en.wikipedia.org/wiki/Rankine_scale

 

[Ibix]

a google (of Rankine) shows there are 3 temperature scales with the letter $R$. The third one is Romer.
See https://en.wikipedia.org/wiki/Rankine_scale

Ah! It was Rankine's scale (degrees the same size as Fahrenheit but with zero at absolute zero) I was aware of. I did wonder why that was appropriate for cheese, and Rømer's scale is much reasonable for that.

Ugh. I like SI.

 

[anorlunda]

Ugh. I like SI.

We all like SI, but we can also smile at the charm of those workmen in Switzerland, Italy and Netherlands following the traditions passed down many generations.

I once worked in a soda factory. There was a recipe in the book: "50000 gallons water, 10000 gallons sugar syrup, 1 gallon grape flavor, and 1 round of #12 purple dye." Nobody knew what a round was. So we assumed it was a typo and added 1 pound. It was a disaster. It turned people's tongues purple. We had to discard the whole batch. Turns out there was a round spoon (about 500 ml) hanging on the wall called "a round" and it was put there just to measure dye. Tradition is hard to change.

 

[hutchphd]

Never heard of it till you mentioned it, and I have been on this ball of rock longer than I care to remember

Yeah me too on all counts...
I will take this opportunity to reiterate my impassioned defense of Fahrenheit

 

[gmax137]

We all like SI, but we can also smile at the charm...

I too like the charm. I like non-SI units, and I like irregular verbs. They keep speech interesting. To me, SI is kind of like Esperanto (and where did that get to?)

I like Whitworth threads and British Std "spanners." I have machines built that way, and like working on them.

When I lived in New England I tapped my maple trees and boiled sap to syrup, my refractometer reads sugar content in "Brix."

Sorry, it's been a long day...

 

[vanhees71]

Well, the SI is a gift to mankind. It's a clean system of units and now finally (utmost) free from any use of specific materials (all except for $\nu_{\text{Cs}}$, defining the second, on which hinge the definitions of all other base units) but based on fixing the (so far known) universal constants of nature. If one could only measure also Newton's gravitational constant to high precision, we could define everything in terms of fundamental constants, i.e., we'd realize Planck units (which in principle could describe everything with dimensionless numbers, but for practical purposes that would be very inconvenient, if you e.g. have to buy goods in units of the Planck mass ;-)).

There's one exception, where I tend to use other units, and that's everything connected with electromagnetism, where I prefer very much Heaviside-Lorentz units, because they are much more "natural" than SI units in measuring electric and magnetic field components in the same unit.

On the other hand also here for practical purposes the SI units are more convenient, i.e., using Ampere instead of the (rationalized) statAmp.

 

[anorlunda]

There are plenty of exceptions where ordinary units work less well than improvised units.

When I heated by wood, I bought firewood by the cord, and I fetched it from the wood pile each day by the sweetheart.

When sailing offshore, I gauged wind by the Beaufort wind scale. That was practically useful whereas meters per second was just a useless number.

Horse farms nearby buy hay by the bale. I buy paper by the ream, apples by the bushel and peck, and plants by the flat. All of those units have a practical value more than their SI equivalents.

I'm sure there are plenty of other examples.

 

[Vanadium 50]

I fetched it from the wood pile each day by the sweetheart.

If that means "sweetheart, fetch me some wood", you live very dangerously!

One of the reasons conventional units often work better is because they were designed to work in that particular setting. Celsius residential/automotive thermostats work in half-degree settings because 1 degree is too large (and 0.1 degree is too small). Our clocks measure days, hours and minutes, rather than simply dividing a day into 86400 seconds. "You start work at second 32,400 and end at 61,200. We usually break for lunch at around 45,000".

SI is the only success of the French Revolution.

 

[anorlunda]

@Vanadium 50 , OMG this must be the sneakiest auto correct ever.

This is what I wrote:

This is what you saw.

When I went back and clicked edit, I found that the original word is still there. So the word is not changed in the text, but it is changed in the real time render. Amazing. We'll see if the rendering changes the screen shots too.

 

[Vanadium 50]

I figured "sweetheart" was just some obscure unit like a hogshead or jeroboam.

 

[vanhees71]

Does that mean the software "rerenders" the text we write by changing words at random? That happened only once in my life before, when a Phys. Rev. article's proofs came back, having been "processed" somehow to "look nicer". The result was that all formulae where incomprehensible garbage ;-)).

 

[Vanadium 50]

The result was that all formulae where incomprehensible garbage ;-)).

Lots of physics papers have all the formulas be incomprehensible garbage.

 

[vanhees71]

Well, but that's usually not just because of a bad conversion from LaTeX to another format the publishers prefer for some reason. Fortunately they finally managed it to print the formulae correctly (typography wise ;-)).

 

[berkeman]

Does that mean the software "rerenders" the text we write by changing words at random?

I don't think this was a random change. Profanity is often changed to stars ***** by the forum software, and in this case the term that @anorlunda used (while valid in the context he used it) was probably on a forum software list of offensive terms. Interesting that it was changed rather than just converted to stars, though.

 

[anorlunda]

Interesting that it was changed rather than just converted to stars, though.

Yes and what an entertaining choice of substitute word. It helped to lighten my day, which is what I needed after the dark mood left over from yesterday.

 

[A.T.]

I don't think this was a random change. Profanity is often changed to stars ***** by the forum software, and in this case the term that @anorlunda used (while valid in the context he used it) was probably on a forum software list of offensive terms. Interesting that it was changed rather than just converted to stars, though.

Jesus Cuddling Christ!

 

[vanhees71]

I don't think this was a random change. Profanity is often changed to stars ***** by the forum software, and in this case the term that @anorlunda used (while valid in the context he used it) was probably on a forum software list of offensive terms. Interesting that it was changed rather than just converted to stars, though.

Then the forum software is inadequate for discussing science, where a precise wording is a necessary prerequisite to express oneself. If you cannot be sure, if you read what the author of a posting wrote, you can as well let bots write postings at random!