How Convenient

[TrimixToo]

It's petrol kilometre-age that's expressed in l/100km, gasoline mileage is in mpgs.

I certainly cannot argue with *that*!

 

[yle]

Yes but using your logic. If he had been an Inuit, he would have scaled it differently (100F to -80F, or 37.8C to -62.2C).

At least Centigrade is logical anywhere on the globe. 100C = boiling point of water, 0c = freezing point of water. Thats a constant.

I totally agree with you that if our primary use of measuring temperatures was freezing and boiling water, then Celsius makes more sense.

But it's not. Our primary use of temperatures is expressing ambient, whether indoor or outdoor, temperatures. And yes, if an Inuit had developed a temp scale they might have a different idea of what a hot and cold day looked like. It's also why, if there was an Inuit that ever created such a scale, it never caught on with the rest of the world.

The fact remains that our human brains like working with scales of zero to 100... which is what the Fahrenheit scale conveniently provides when measuring ambient temperatures. At least for the 7.4 billion people that don't live in the Arctic Circle.

 

[dmaziuk]

It's also why, if there was an Inuit that ever created such a scale, it never caught on with the rest of the world.

There's a call from Innuit Anti-Discrimination League on line one for you.

... which is what the Fahrenheit scale conveniently provides when measuring ambient temperatures. At least for the 7.4 billion people that don't live in the Arctic Circle.

You have a call from 7.1 billion who don't live in the US on line two.

 

[Magnus Lundstedt]

I totally agree with you that if our primary use of measuring temperatures was freezing and boiling water, then Celsius makes more sense.

But it's not. Our primary use of temperatures is expressing ambient, whether indoor or outdoor, temperatures. And yes, if an Inuit had developed a temp scale they might have a different idea of what a hot and cold day looked like. It's also why, if there was an Inuit that ever created such a scale, it never caught on with the rest of the world.

The fact remains that our human brains like working with scales of zero to 100... which is what the Fahrenheit scale conveniently provides when measuring ambient temperatures. At least for the 7.4 billion people that don't live in the Arctic Circle.

I don't live on the artic circle, for me a realy cold day is -40°, regardless if you use F or C.


On the other hand, when calculating pressure and temperature differences in a scubatank (or any other thing when use absolute temperature), i use Kelvin. And to convert between ° Celcius and Kelvin is realy easy, i can do it in my head. to convert betwen K and °F is a little more complicated. KISS!

T(K) = T(°C) + 273.15
T(K) = (T(°F) + 459.67) × 5/9

I prefere the simple one.

So, if i have a scubatank that is about 25°C andthe temperature rise to 55°C when i have it stored in my car a sunny day, i have a temperature rise in ~10% with gives about 10% higher temperature.

273.15+25 = 293.15 ~ 300K and a temperature rise of 30K is about 10% so if i have 200 Bar pressure in the tank at 25°C it will be about 220 Bar if it rise to 55°C

If I would like to do the same in Farenheight i need to do more math, and i cannot do it in my head, maybe if i was a human calculator, but i am not.

 

[Snoweman]

T(K) = (T(°F) + 459.67) × 5/9

I think this is a little off. Here's what I found: K = 5/9 (° F - 32) + 273

 

[Blasto]

zero to 100... which is what the Fahrenheit scale conveniently provides when measuring ambient temperatures. At least for the 7.4 billion people that don't live in the Arctic Circle.

I don't feel it to be convenient at all.

Zero on the Fahrenheit scale has absolutely no meaning: for most purposes, -10°F is just as cold as +10°F (as the latter tends to be more humid), and most importantly both call for the same clothes.

+100°F also has very limited practical meaning, in determining if one is "a bit sick" or "too sick". The typical temperature on the equator is about +90°F. And temperatures above +95°F are limited to very dry climates, where they're much more tolerable - in other words, above 100°F can feel cooler than below.

On the other hand, 0°C has a very useful meaning: if it's below, it might snow, otherwise it might rain. Snow means I need a hat, but not an umbrella. Rain means I need an umbrella, but a hat is optional. That's extremely useful information to have.

I never need the granularity of even 1°C for judging the weather, much less anything smaller. In practice, Fahrenheit units are usually used in an increment of 5°F and 10°F - a clear sign of a unit that's not been sized right.

 

[Magnus Lundstedt]

I think this is a little off. Here's what I found: K = 5/9 (° F - 32) + 273

We can try both:

I try -40°F first

T(K) = (T(°F) + 459.67) × 5/9

T=(-40+459.67)* 5/9
T=419.67*5/9
T=(459.67*5)/9
T=2098.35/9
T=233.15 K

T(K) = 5/9 (T(°F) - 32) + 273

T=5/9(-40 -32) +273
T=(5/9)*(-72)+273
T=-40+273
T=233

The first one is spot on, second allmost correct, just should had 273.15 instead of 273, but thats just a matter of precition.

The second one, if using the correct T(K) = 5/9 (T(°F) - 32) + 273.15 instead, is acctualy a workaround converting first to °C [T(°C) = 5/9 (T(°F) - 32)] And then add 273.15

If you instead start with °C you just have to add 273.15, and that I can do in my head.

 

[Asteve]

If the base 10 system is so great, why is the whole world still using the 12 hour day?
I can count to 12 using the fingers joints on one hand and using the thumb to hold my place. Try that with the base 10 system.

 

[Magnus Lundstedt]

I never need the granularity of even 1°C for judging the weather, much less anything smaller. In practice, Fahrenheit units are usually used in an increment of 5°F and 10°F - a clear sign of a unit that's not been sized right.

Granularity is just a mather of how many decimal points you use.

My home thermometer have .1°C granularity (but probably not accuracy), but i have used thermometers for other applications with .001°C granularity.

It's like the meter, not so accurate, if you should only use full meters, to for example describe how tall someone is, most adults should be 2m i am acctualy 1.83m = 18.3dm = 183cm = 1830mm = 1,830,000μm

1 meter = 10 decimeter = 100 centimeter = 1,000 millimeters = 1,000,000 micrometers = 1,000,000,000 nanometers, and so on.

And it goes the other way too, 1 kilometer = 1,000 meter. kilo=1,000, mega=1,000,000, giga=1,000,000,000, terra=1,000,000,000,000

So, the earts cicumferance of ~40,000,000m can be written as 40,000 km (kilometer), or as 40 Mm (megameter).

And if we talk weights, my weight is about 100,000 g (gram), but it would be inconvienient to write or say, so instead i write (say) 100 kg (kilogram).

And everything is connected, but sometimes the base units is of, but not by some arbitrary number, always in steps of ten. i litre for example, is the volume of a cube with the side of 0.1m and a litle of fresh water have the mass of 1kg (at a temperatore of 277.15K)

 

[BRT]

You have more fractional drills than I do, but I can bore any size hole I want. So there! ;-)

I also have annular cutters up to 6", but I have to use those on a mag drill or the mill,