Why do we need different temperature scales?

[sophiecentaur]

But on a scale of, say, -7 to +19 how do you rate each temperature method?...okay I'll stop.
My major point is that there is much to recommend changing the US system to metric but there is no compelling reason to discontinue Fahrenheit and I would argue some reason for keeping it. One need not throw out the baby with the bath water.

As a Scientist, I should have thought that a system that tracks the Kelvin scale would be very desirable. I am really amazed how people (on PF even!) appear to be so emotionally attached to Fahrenheit.
I have the same problem with the Mile. Why the UK still uses the mile, in amongst all the metric units, is hard to explain. When moving to decimal coinage in the early seventies, we had loads of reaction in the UK but, because they had no option, the public just adopted it. We still ask "what's that in old money?" but for all sorts of different unit comparisons (not just money). That question is used ironically and is often a dig at old fashioned ideas in general.

It's really not a big deal.

That's the most relevant comment in the whole thread.

 

[sophiecentaur]

Suppose you were to devise a temperature scale. How would you decide what the units were?

If I had any sense then I would base it all on convenient fixed points and so would Scientists on the Planet Zog. If they were (sensible) carbon-based life forms then odds are that they would also choose the melting and boiling points of water (OK - local atmospheric pressure etc. could affect their Standard Temperature and Pressure choices). It's unlikely that 0K would have been involved when their temperature scales were invented. The -273 number would just have been 'found' somewhat later. If the Zoggians happened not to have five digits on a hand then they might not be using a decimal system but you can bet they would have used degrees between melting and boiling points, based on their number system. Not "arbitrary" but linked to their arithmetic system - like our 100 degrees.
Interestingly (?) the Zoggian absolute zero would also be at -2.73 times their basic melting / boiling interval.

 

[hutchphd]

I'm with @vanhees71 for my scientific scale...give me eV all the time. The Zoggians could do their derived single point calibration from any fixed energy event (say Hydrogen alpha) assuming they are technically savvy.
This still leaves the problem of the weather guy on the tube. I don't think "tomorrow's high will be 1/40 eV" is likely to catch on. Nor would Celsius ab initio , I contend. This is a very small point but the context is larger. I am a scientist to my very core, but the "natural" unit for measurement are not always the "best for everyone" units.
Now I must get in my car and drive 30 miles per hour to the grocery...I will not drive at 4x10^-8c. Perhaps we would all be better scientists if we did, but it would get tedious!

 

[sophiecentaur]

In the same vein. I just learned something this morning about the good old imperial foot. Apparently, UK cartographers and surveyors use(d) decimal feet in their height measurements. At a talk on old benchmarks, the guy brought out surveying poles with tenths of a foot markings. It's been that way for ages, according to him. I wonder it that's standard practice in the quaintly imperial United States.

 

[hutchphd]

My brother is a land surveyor (retired) and I will ask him. Was there a name for the unit? I have not seen it myself. I have of course seem rulers with the inches delineated in tenths (I even have a set of calipers so delineated and of course micrometers are always in mils). Yes the law was on the books to metrify the US (Jimmy Carter's impetus) but Mr Reagan, in his infinite Republican wisdom, made it go away.
Some time you will need to describe why the British have so damned many different styles of screw threads.

 

[JT Smith]

One gram weighs what one dollar (bill) weighs.
With that demonstrable comparison, one pound of dollars(the individual paper money bills) would weigh about 454 grams (taking its equivalent in mass, since 'mass' and 'force' are not the same thing).

Demonstrable? I suspect that dollar bills do not weigh 1.000 ± 0.001g, which is how precise their weight would have to be to guarantee that 454 of them weighed 454g.

In any case, my point was that it's too small a weight for humans to detect easily. If you put a dollar bill in your hand you will feel the paper on your skin. But if insulate your hand from the sense of touch you almost certainly will not feel the weight.

But the weight of 28 bills (about an ounce) is much more easily detectable.