3 ms·

> Ew, multiplicative temperature comparisons in unspecified units In the previous paragraph he's said that water boils at 100 C

deleted 3y ago
[deleted]
tempodox 3y ago
I'd expect a multiplicative temperature comparison to refer to Kelvin, not Celsius.
- jebarker 3y ago
  Ah, TIL that Celsius is "non-multiplicative". From ChatGPT: "When using Celsius as the unit for temperature, it is not meaningful to say that one temperature is a certain number of times higher than another. The Celsius scale is based on the freezing point (0°C) and boiling point (100°C) of water, which are not absolute values. Thus, the Celsius scale has negative values, and simply multiplying temperatures does not provide an accurate representation of relative differences. If you want to compare temperatures in a more meaningful way, you should use the Kelvin scale. The Kelvin scale is an absolute temperature scale, with its zero point (0 K) representing absolute zero. In this scale, it is appropriate to say that one temperature is a certain number of times higher than another because the scale starts at an absolute zero point. To convert Celsius temperatures to Kelvin, add 273.15 to the Celsius value. Once the temperatures are in Kelvin, you can then make meaningful comparisons using multiplication or division."
  - _a_a_a_ 3y ago
    Yeah, kelvin strictly speaking, but for reactors on earth (not in 3 kelvin outer space) with a baseline earth-ambient temperature, perhaps multiplicative C is valid, very approximately? I don't know, I guess I'm asking.
    - ethbr0 3y ago
      Specifying "times" in Celsius is fine... as long as you stay either positive or negative. Implying that you can only specify multiples in Kelvin is being pedantic.
      - sgjohnson 3y ago
        But not really. 100°C times two is not 200°C. 100°C times two is 473°C
        ethbr0 3y ago
        Howso? If the conversion to Kelvin is additive (as opposed to something more complicated), and multiplying in Kelvin is fine, then how is multiplying effectively-unsigned in Celsius not fine?
        sgjohnson 3y ago
        Ok, another example. Is 10°C 10 times as hot as 1°C? No. Multiplying kelvin is fine because kelvin is an absolute scale.
        _a_a_a_ 3y ago
        > No. For a given baseline, perhaps yes?. Kelvin has its baseline inherent, for C you can pick what you like if you're clear about it. Perhaps. (Edit: and using only positive or negative temps as pointed out above)
        ethbr0 3y ago
        Yes. Parent's spaghetti examples weren't the most illustrative. What I believe they're griping about is that "10°C does not have 10x as much heat as 1°C." In actuality, "10°C has 10x the difference in heat that 1°C has relative to the freezing point of water." So it's a comparison definition quirk, not a numerical one.
- deleted 3y ago
  [deleted]
- hermitcrab 3y ago
  Or Rankine for a US reactor, surely? ;0)

deleted 3y ago

[deleted]

tempodox 3y ago

I'd expect a multiplicative temperature comparison to refer to Kelvin, not Celsius.

jebarker 3y ago
Ah, TIL that Celsius is "non-multiplicative". From ChatGPT: "When using Celsius as the unit for temperature, it is not meaningful to say that one temperature is a certain number of times higher than another. The Celsius scale is based on the freezing point (0°C) and boiling point (100°C) of water, which are not absolute values. Thus, the Celsius scale has negative values, and simply multiplying temperatures does not provide an accurate representation of relative differences. If you want to compare temperatures in a more meaningful way, you should use the Kelvin scale. The Kelvin scale is an absolute temperature scale, with its zero point (0 K) representing absolute zero. In this scale, it is appropriate to say that one temperature is a certain number of times higher than another because the scale starts at an absolute zero point. To convert Celsius temperatures to Kelvin, add 273.15 to the Celsius value. Once the temperatures are in Kelvin, you can then make meaningful comparisons using multiplication or division."
- _a_a_a_ 3y ago
  Yeah, kelvin strictly speaking, but for reactors on earth (not in 3 kelvin outer space) with a baseline earth-ambient temperature, perhaps multiplicative C is valid, very approximately? I don't know, I guess I'm asking.
  - ethbr0 3y ago
    Specifying "times" in Celsius is fine... as long as you stay either positive or negative. Implying that you can only specify multiples in Kelvin is being pedantic.
    - sgjohnson 3y ago
      But not really. 100°C times two is not 200°C. 100°C times two is 473°C
      - ethbr0 3y ago
        Howso? If the conversion to Kelvin is additive (as opposed to something more complicated), and multiplying in Kelvin is fine, then how is multiplying effectively-unsigned in Celsius not fine?
        sgjohnson 3y ago
        Ok, another example. Is 10°C 10 times as hot as 1°C? No. Multiplying kelvin is fine because kelvin is an absolute scale.
        _a_a_a_ 3y ago
        > No. For a given baseline, perhaps yes?. Kelvin has its baseline inherent, for C you can pick what you like if you're clear about it. Perhaps. (Edit: and using only positive or negative temps as pointed out above)
        ethbr0 3y ago
        Yes. Parent's spaghetti examples weren't the most illustrative. What I believe they're griping about is that "10°C does not have 10x as much heat as 1°C." In actuality, "10°C has 10x the difference in heat that 1°C has relative to the freezing point of water." So it's a comparison definition quirk, not a numerical one.
deleted 3y ago
[deleted]
hermitcrab 3y ago
Or Rankine for a US reactor, surely? ;0)