[devy]

It's astonishing to me that I discovered the other day that Fahrenheit is only used by United States, its territories and associated states (all served by the U.S. National Weather Service), and 3 other small Caribbean countries. All other countries in the world are using Celsius scale from metric systems.[1]

Can someone shed some lights why is that?

https://en.wikipedia.org/wiki/Fahrenheit#Usage

[wayn3]

Because water is arguably the most important substance to mankind.

In the celsius system (and at standard pressure and bhawawa please point out technicalities) - water freezes at 0°C and boils at 100°C. That's pretty simple to remember and makes actual sense.

In fahrenheit, body temperature was supposed to be 100°F but its not because when the guy measured his temperature, he had a fever. Congrats dude. First strike.

It freezes at around 30°F but not quite. The scale just doesn't make sense for any intuitive application.

If you think that body temperature should determine the scale of temperature measurements, think about how often you need to know your body temperature vs. how often you need to know how hot it is outside. "is it tornado season? nah, its only about 0.7 body temperatures outside". Besides, to anchor a scale, you need 2 reference points. Not just one. Fahrenheit is just a turd.

On top of that, Celsius scales just like Kelvin. 0 Kelvin is the point of absolute zero. The point of "No temperature" - to keep things simple.

0°C is 273.15K and 100°C is 373.15K - which means that Celsius is essentially Kelvin (the unit that makes scientific sense) adjusted to a level that makes sense for common man applications.

That explains why everyone is using Celsius. Nobody can tell you why the US does not. Its clearly because they are some very special snowflake. Same reason they use retarded units like inches, feet, yards, miles, ounces and pounds.

Metric systems be damned.

[david-given]

The business about the fever is a myth. Fahrenheit's original fixed points were a mixture of ice, water and ammonium chloride, at 0, and normal human body temperature --- at 96. He then redefined it in terms of the freezing point of water and human body temperature, at 32 and 96, so as to have 64 degrees between them.

After his death in 1776, it was redefined based on the freezing and boiling points of water at STP, at 32 and 212 (a difference of 180). So in fact it uses the same fixed points as Celsius, and has for hundreds of years.

Also, you have Celsius and Kelvin backwards: Kelvin was originally formulated to use the same sized degrees as Celsius, not the other way round. Celsius was first. (Although Celsius is now defined in terms of Kelvin.) See also Rankine, which is the Kelvin equivalent to Fahrenheit: absolute zero is 0, the freezing point of water at STP is about 492, and boiling point is about 671.

Did you know that the original Celsius scale ran from 0 at boiling point to 100 at freezing point, i.e. backwards? It was reversed after his death. Fahrenheit didn't make that mistake!

[stan_rogers]

The body temperature the Fahrenheit scale was made to work at was axillary (armpit) temperature, at 96°. That's a multiple of 32°, and both are evenly divisible by 16, 8, 4, and 2, making marking of the scale easy. Both are common temperatures that a person would be likely to experience (whereas 100°C is something you'd hope not to experience, but rather to observe). That leaves zero as "frikkin' cold" by most European standards. It's a perfectly reasonable scale if you're not obsessed with base-10 values.

[int_19h]

It's hard to not be obsessed with base-10 values, when your numeral system is base-10.

I am sympathetic to the argument that 12 (but not 16) would make a better base. But that argument only works if it's uniformly applied bottom up - base-12 everywhere, and then we define base-12 metric prefixes, use 144 degrees between defining points for temperature etc.

As it is, the incoherent mix of base-16 and base-12 that is common for American customary measures, and base-10 used to actually write them down, is a mess.

[wayn3]

if you think that they're "easily divisible by 2", why not tell me what 832 is in terms of exponents of 2.

Thought so. Most people have enough difficulty understanding multiples of 10. No need to make it more difficult for the mentally challenged. For us scientists, factors of 10 prove really helpful.