Based on human perception, based on water chemistry, based on physics.
You’ll be shocked to learn that the distance in Kelvin is also adjusted to water “chemistry”, albeit changing the aggregate state seems more physics to me, since no molceules are reacting with each other.
You can’t change the aggregate state of a single molecule, or how do you mean that? Excluding plasma.
you can of a lot of molecules though. and tgat is classically “physics” rather than “chemistry”. Classical chemistry is reactiona between atoms or molecules to form new ones.
If you get deeper into it, the lines between chemistry and physics blur anyways.
Thankfully that has been redefined using the Boltzmann constant, so now anyone in the universe can agree on °C and K without needing to measure any Vienna standard ocean water.
Zero Fahrenheit is the freezing point of brine (of a certain concentration). That’s water chemistry.
Originally, 90F was based on the average human body temperature, but that later changed to 96F, which just goes to show how arbitrary that scale is.
It’s all arbitrary. Someone just decided to base a scale off of something and that something isn’t fixed from the start. The meter used to be based off the measurement of the earth, but now it’s based off of light.
It’s just some random semi-useful starting point that we all agree on so we’re using the same language.
The meter did not change, science has merely defined it more precisely and reliably over time. It is a measure of length, still one 40 millionth of the circumference of the earth through the poles. Other definitions like the speed of light definition will give you the same result. These newer definitions have reduced uncertainty and added ways to reproduce its length by natural means. But it’s not like the ‘original’ meter was shorter or longer than today’s meter, at least not by any noticeable margin.
Shifting the top end of a temperature scale by over five percent of the scale is a bit more arbitrary than that.
I’d like to propose a discussion between a person from Arizona and a person from Alaska to define what is “Really hot outside”
Im from Texas, and 100F is “stay inside in the AC” weather. I bet an Arizonan would say the same.
Being from a particularly hot or cold location doesn’t make you immune to heat or cold, it makes you a connoisseur of heat and cold. You get better at recognizing gradations of extreme temperature (knowing which are uncomfortable and which can literally kill you if you’re not careful), you learn how to plan ahead and dress for the weather, and you develop emotional coping systems for extremes.
But if it’s either 100°F or 0°F, no matter where you’re from, that’s a temperature to be wary of.
Fun fact time, -40F is -40C.
And 575F is 575K
Fahrenheit makes sense for humans. Most of your day to day climates are in the 0 to 100 scale, and every 10 degrees is a noticeable level change.
- 100 super hot day, approaching unsafe without counter measures
- 90 really hot day, slightly annoying and should take precautions
- 80, hot day, more annoying than anything
- 70, beautiful day, enjoy it
- 60 not to bad, if it’s windy you could be slightly on the cold side
- 50 long sleeves or maybe a hoodie
- 40 definitely a jacket, and hat
- 30 full on coat, scarfe, and hat
- 20 multiple layers of out for a while, maybe double pants
- 10 annoyingly cold, need to start thinking about the safety precautions
- 0 and below, temperature now measured in hold long you can be outside before danger
Celsius makes sense for science stuff because it’s derived from science stuff, so things like calories and energy work with it. But it doesn’t really apply to everyday life as well. So it actually makes sense to use both units for the things the are good at.
It depends on what you were raised with. For me I have all these relevant points in my head for C. 25 is nice, under 20 you slowly need to dress longer stuff. Over 30 is hot, over 40 sucks hard, over 50 can become deadly soon. Body temp is around 37.
Just an fyi, 100F is not “unsafe without counter measures” level of hot. That would be around 115+F. I say this as someone from a city that regularly hits 120F during the summer. 100 you can still get in your car, 115+ you need to wear gloves or else you’ll get 3rd degree burns. 100 have to buy pizza for lunch, 115+ just bake a pizza in your car.
Being from outside of the US I’m used to Celsius for everything, so I can make the same list, the numbers are just not whole 10s and I would probably round to nearest 5.
why are you being so heavily downvoted? you’re not even saying anything controversial.
But it doesn’t really apply to everyday life as well. So it actually makes sense to use both units for the things the are good at.
It’s funny to assume that all people using Celsius are unable to ascertain how they will feel outside based on the temperature value.
I mean, I understand that round numbers are cute, but we are able to handle numbers ending in 5 as well as numbers ending in 0.
It’s just designed with a slightly different set of assumptions.
Instead of water freezing and boiling 100° apart, it’s 180° in fahrenheit. That makes it so that they’re on the opposite sides of a temperature gauge, and a degree of rotation of the gauge matches a degree of temperature.
Instead of zero being the freezing point of water under specific conditions, it’s a brine solution whose temperature will stabilize in a way that’s useful for using as a calibration point.
Stripped of its context, it’s odd. But it’s not irrational, just no longer consensus as the standard, and as such deprecated.
Since when is 0°C “fairly cold” it’s literally freezing.
0°C is completely fine with jeans and a thick jacket, especially when it’s sunny and there isn’t much wind. It’s cold, but there’s probably not much ice or snow, if anything, probably mostly slush.
Compared to say -20 C where you should have a good ski jacket and ski pants, warm shoes and socks, generally multiple layers everywhere, winter gloves and so on.
It can be -20 C and you can be still fine with jeans and a jacket if it isn’t windy.
What I’m saying is temperature alone doesn’t tell you the whole story.
Humidity. I’m guessing you don’t live in a humid place because freezing temps are horrifically cold here. You will need a winter coat and multiple layers of your going to be outside for a while. I layer long Johns under my pants and wear my parka and a light jacket as well as 2 layers of socks. Everytime a northerner comes here they are shocked at the cold/heat. That’s because the air here is full of water to the point that you will actually get wet just from the humidity, not even sweating.
I’ve been in -37C snow shoveling. Since then 0C doesn’t even register as cold to me
Yep, and I’ve been in 110C in sauna. It’s pretty fucking hot but not death
You’re failing at pretending to be human. We’re literally made of water. About 80% of us is water.
I knew someone would say this. We don’t freeze solid at 0 Celsius however.
Many places in the US, particularly in the East and Midwest, experience average temperatures at or below freezing (32°F) in the winter, so while it’s definitely cold, it’s often not considered really cold. It’s not until you move further towards 0 and the negatives that most people in that area feel really cold (like weather advisory levels). Of course the further north you go, the more normal those temps are. Likewise, it’s definitely not unheard of for temps to hit 100°F (37°C) in the Southwest, but it would be considered pretty hot for much of the country, and even Texas suffers at sustained temps like that.
Freezing temps here are definitely considered very cold. Cold enough that you need multiple layers and you should be wrapping your pipes to prevent freezing. It’s very humid here. Our freezing is insanely cold. Like chills you to your bones cold. Our hot here is insanely hot as well.
The temperature that water freezes at is only fairly cold weather by a lot of people’s perception.
I’d call it “chilly”. No jacket for running to the mailbox, or if I’ll be outside for half an hour or so. Light jacket otherwise. I don’t expect it to snow, since it’s not actually cold enough usually, and there won’t be ice on the ground unless it’s just warmed up.
So it might be “freezing”, but that doesn’t make it cold.
It’s almost like being ‘fairly cold for humans’ is a wide range, and subjective, therefore useless as a baseline.
Well I’d say that’s why op chose the adverb “fairly”, it gets across that it’s a wide range and lacks specificity.
Not completely useless as a baseline, but fairly general.
True, but that’s also not super relevant to the merits of a temperature scale. Fahrenheit isn’t actually based off of human subjective temperature perception, it just coincidentally lines up a bit closer with the comfortable range for people in northern temperate climates.
Before it’s redefinition in terms of Celsius, fahrenheit was defined by a particular temperature stable brine solution (easy to replicate for calibration), and with the freezing and boiling points of water set to be 180 degrees apart, because of the relationship with a circle.
People decided we liked base10 adherence more than trigonometry, and then everyone adopted Celsius, so we should use Celsius. Doesn’t make fahrenheit some sort of random scale, just deprecated.
100° outside is dead
