this post was submitted on 09 Sep 2024
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[–] lime@feddit.nu 44 points 2 months ago (26 children)

only if you grow up with fahrenheit.

[–] alcoholicorn@lemmy.ml 3 points 2 months ago* (last edited 2 months ago) (2 children)

100F was defined as the human body temperature (The guy they used had a cold or something so it's off by a degree and a half.)

That's useful for perception of heat. When the dry bulb gets above 100F, wind only cools you down by sweat evaporation, and when the wet bulb gets above 100F, even that can’t cool you down, and you will die if you don’t get to a cooler or drier environment.

This is more intuitive than 36.5C.

[–] lime@feddit.nu 7 points 2 months ago* (last edited 2 months ago) (1 children)

what Fahrenheit used for his endpoints was 1) the melting point of a brine mixture that he didn't write down the ratio of, and 2) his wife's armpit.

those "bulb" things is something i only ever hear of from americans. it's never used here.

and I fail to see how two numbers are somehow differently intuitive. they are just numbers. also, 36.5 is too low. it's pretty much 37.0 now, because average body temp has interestingly enough shifted since he took those measurements.

[–] Voyajer@lemmy.world 7 points 2 months ago (1 children)

What does Europe use for apparent temperature measurement then? Just humidity and not evaporation?

[–] lime@feddit.nu 2 points 2 months ago

temperature, wind speed and direction, and humidity are given separately. regular news report style forecasts don't give humidity at all.

[–] Venat0r@lemmy.world 1 points 2 months ago (2 children)
[–] Voyajer@lemmy.world 5 points 2 months ago

Dry bulb is a normal temperature reading with say a thermometer. Wet bulb is that same thermometer but it is wrapped in a wet cloth to simulate evaporation of sweat.

The purpose of wet bulb temperature measurement is to fix the dangerous temperature threshold at body temperature instead of having to adjust for humidity. So if the wet bulb temperature crosses 35C/95F you know that it is dangerous to even be outside because your sweat can't even evaporate enough to prevent you from overheating just standing in the shade.

[–] alcoholicorn@lemmy.ml 4 points 2 months ago* (last edited 2 months ago) (1 children)

Dry bulb is the temperature independent of humidity. Wet bulb is has a wet cloth on the thermometer bulb. This simulates how much sweat cools you in the current humidity and wind.

Measuring humidity instead and cross-referencing to get heat index is more common these days, but IMO it's worse. 120 in the desert vs 120 heat index due to humidity is the difference between someone using a hair dryer on your face and getting cooked in a steam room, and it doesn't consider wind and cloud cover.

[–] flerp@lemm.ee 2 points 2 months ago

Wait, doesn't everybody walk around with a pocket psychrometric chart?

[–] frezik@midwest.social 2 points 2 months ago (5 children)

So you're saying that 0 and 100 aren't intuitively obvious? I find that really strange when it's doing a better job keeping to base 10 than the metric system in this particular use case.

[–] lime@feddit.nu 12 points 2 months ago* (last edited 2 months ago) (10 children)

the numbers may be, but if you asked me to tell you what they feel like i would have to convert them to celsius first. where i live temperatures are generally between -30 and +30, and i could tell you in an instant what I would wear for a given temperature in that range. 50F though? no clue. since it's right between 0 and 100 i guess it would be just right, temperature wise, so t-shirt and long pants?

[–] frezik@midwest.social 5 points 2 months ago (1 children)

Can you remember that at temperatures near 0F and 100F, you need to take special precautions when going outside? The rest is a matter of getting used to what the numbers mean, but those are very intuitive danger points.

[–] lime@feddit.nu 9 points 2 months ago* (last edited 2 months ago) (10 children)

-18 is such an arbitrary place for "special precautions". at 0, I know to start driving more carefully since the roads ice up. at -15, i know to wear long johns. at +15, i know to start using a thinner jacket. at -30, i know to use a thick hat and wax on my cheeks to prevent the blood vessels from rupturing. at +30, I know to use a large hat and sun cream on my cheeks to prevent them from burning.

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[–] IrateAnteater@sh.itjust.works 11 points 2 months ago (8 children)

When it comes to a single number on a scale, whatever you grew up with will be more "obvious". 100F doesn't give me any more information than 38C does. The whole "base 10" thing only matters if you are actually doing some math to that number.

[–] frezik@midwest.social 2 points 2 months ago* (last edited 2 months ago) (3 children)

Base 10 makes it much easier to remember.

When was the last time you did math related to temperature?

[–] IrateAnteater@sh.itjust.works 7 points 2 months ago

For day to day use, it's just a single number, no one is doing any conversions, etc, with the number. That was my point. There's nothing to remember. Do you forget what 72F feels like? Do you have to scale it in your head?

base 10 is literally just 0-9 so yeah, everyone remembers that.

scaling based on the base 10 figure makes conversions easier, so there's that.

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[–] yetAnotherUser@discuss.tchncs.de 9 points 2 months ago (1 children)

For Celsius, 0 is freezing cold and 100 is boiling hot - that's intuitive too.

I have literally never felt 0°F in my life and couldn't tell you how cold it is, just that it's very cold. I believe everyone has a rough understanding how 0°C and 100°C feel though.

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[–] hemko@lemmy.dbzer0.com 4 points 2 months ago* (last edited 2 months ago) (17 children)

No, they're not. I couldn't tell what those numbers mean even if you asked, but I can tell what 0°C outside feels, and what 100°C sauna feels. I can also tell that 21°C is a nice ambient temperature for chilling, and 15-20°C is ideal for most outdoor sports.

Yeah sure those are not necessarily nice round numbers, but I've used the scale all my life so it's intuitive to me, same as the Fahrentrash is intuitive to you

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