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ginkoyesterday at 11:10 PM7 repliesview on HN

Not to be a stickler (ok I like being a stickler) but temperature delta, especially deltas between degrees celsius, should be given in kelvin. A 1.8K difference makes sense. A 1.8C difference would be 274.8 kelvin!


Replies

hexer292today at 12:11 AM

This is probably the most ridiculous comment I've read in the history of this website.

There is no difference in the amount of energy 1 degree Celsius delta and 1 degree Kelvin delta represents.

The only (and I really mean only) difference is how zero energy is defined. It is not possible to have negative energy, and that zero Celsius represents the freezing point of water is an artifact of convenience, not of absolute definition.

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atombendertoday at 12:19 AM

Celsius is not an absolute scale, but that isn't a problem for deltas: (10C - 5C)=5C, (10K-5K)=5K. Celsius is only problematic when multiplying or dividing. 10C is not twice as hot as 5C.

hn_throwaway_99yesterday at 11:16 PM

That makes no sense. A difference between a read of 37C and 38.8C is still 1.8C.

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altairprimetoday at 12:28 AM

"A 1.8C difference" expands as "A difference of 1.8C" expands as, and here's the ambiguity, either:

"An absolute difference of 1.8C, or 274.8K, measured between A and B"

or

"A relative difference of 1.8C, or 1.8K, is added/subtracted to A/B in order to reach B/A"

I don't think the context-free variant with K will improve understanding and decrease confusability in this discussion context, but I appreciate the pointer about it in general. I'll take a lot more care around it in a future thread about space apparel!

alistairSHyesterday at 11:46 PM

Kelvin and Celsius use the same unit magnitudes. It would be a 1.8* difference either way.

hightrixyesterday at 11:33 PM

To be a stickler, communication requires respect for your audience. The vast majority of everyone understands a 1.8 degree C delta. I would argue that very few people anywhere would understand a temperature delta given in kelvin.

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