• Dale@lemmy.world
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    1 day ago

    Kelvin is great for math and science. But daily life? Dude. The weather does not need to be reported relative to absolute zero just like the speed of your car doesn’t need to be reported relative to the sun. Also Fahrenheit did famously use his wife’s armpit for the 100 mark that’s why it’s “close to body temperature”.

    Another fun fact human body temperature has not always been 98.6 and has been getting lower.

    • Sludgeyy@lemmy.world
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      1 day ago

      I didn’t know about the arm pit thing.

      To create a scale you have to start somewhere.

      To think he measured his wife arm pit to be 100°F and then said, let me make a salt brine mix to get to 0°F. Seems completely backwards.

      They had no idea about absolute 0 back then. Coldest thing you can create in a lab consistently at the time was a reasonable 0°

      But that’s where the scale starts and everything is based on.

      Could he have created a colder one but wanted 100° to be close to body temperature. Maybe. But that’s not weird. 0 and 100 are important numbers. Most people have an armpit and a way to calibrate their thermometer in a pinch. Axillary method, armpit, is a legit way to take someone temperature.

      Fahrenheit has 2° compared to 1° of Celsius. 98, 99, 100, 101. (37, 37, 38, 38). Being 1° off in F isn’t as much of an error as being 1° off in C.

      You can’t just boil water and say, that’s 100°C! Pressure matters. To boil water at standard pressure was difficult to recreate at the time. Same for freezing.

    • Sludgeyy@lemmy.world
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      1 day ago

      That’s the whole point of using Celsius or Fahrenheit. They are both just different representations of Kelvin. But Kelvin is absolute.

      If you want your weather scale to go -20 to 40 or 0 to 100. Is debatable.

      0°F to 100°F is better for weather

      0°C to 100°C is better for water temperature

      If you know C, there’s no need to learn F for the weather.

      If you know F, there’s no reason to learn C for the weather.

      You don’t need to know F or C to read a thermometer. 375°F or 190°C are just numbers you might bake cookies at. No one knows how 375°F or 190°C “feels like”

      Things you need to know is if 90°F or 32°C water is safe to get in. Over 100°F is getting dangerous, Over 40°C is getting dangerous.

      Normal house hot water is 50°C or 120°F.

      Time to cause burns:

      120°F or 50°C More than 5 minutes

      130°F or 55°C About 30 seconds

      140°F or 60°C Less than 5 seconds

      150°F or 65°C About 1.5 seconds

      160°F or 70°C About 1/2 a second

      Aslong as you know a system, you’re fine. Fahrenheit isn’t like the other US customary units. It is based on the exact same thing Celsius is, Kelvin. Just shown in different numbers. Something like a quart to gallon is a completely made-up measurement and horrible.