If you want "twice as hot" to be meaningful, you have to use an absolute scale, either Kelvin or Rankine. (1 K = 1.8 °R)
Doubling absolute temperature doubles the pressure (at constant volume) or volume (at constant pressure) of an ideal gas. This gets <i>really important</i> when it comes to compressing and expanding air and other gasses.<p>Room temperature is approximately 293 K, twice that is 586 K / 595 °F / 313 °C. Hotter than your typical oven cooking temperature.<p>We often don't realize how warm the world we live in truly is, from a physics standpoint.
A useful habit (which I think I picked up while studying physics at sixth-form) is to describe temperature intervals in “Celsius degrees” (and specific temperatures in “degrees Celsius”).<p>So a temperature of 43 degrees Celsius is 18 Celsius degrees hotter than 25 degrees Celsius.<p>32 Fahrenheit degrees are equivalent to 18 Celsius degrees; but 32 degrees Fahrenheit is equivalent to 0 degrees Celsius.<p>(There's no real need to do this when using absolute units, but I'd still pluralise the interval and not the absolute value: 316 kelvin is 25 kelvins hotter than 291 kelvin.)
<a href="https://en.wikipedia.org/wiki/Level_of_measurement" rel="nofollow noreferrer">https://en.wikipedia.org/wiki/Level_of_measurement</a><p>I learned this relatively late in my life, but it was so an insight. From one hand it is just obvious facts, but from the other hand they are nicely categorized and so feels like you have learned something completely new.
An <i>affine space</i> is a tuple (𝗔, 𝗩) where 𝗩 is a vector space and 𝗔 has the same structure as 𝗩 but has "forgotten its origin"; ie. unlike a vector space, has no privileged zero point. As such, multiplication by a scalar is not meaningful, and neither is the addition of two elements of 𝗔. The elements of 𝗔 are called <i>points</i>, and the elements of 𝗩 are <i>translation vectors</i>, or simply <i>translations</i>. The fundamental operations are:<p>(−): 𝗔 × 𝗔 → 𝗩 — gives the translation from a point to another point, and<p>(+): 𝗔 × 𝗩 → 𝗔 — applies a translation to a point.<p>(For convenience we can also write 𝒂 − 𝒗 = 𝒂 + −𝒗 for all 𝒂 ∊ 𝗔, 𝒗 ∊ 𝗩).<p>The Celsius and Fahrenheit scales are affine, and technically should have separate units for temperatures and temperature <i>differences</i> so that mishaps like in TFA would be less likely to happen.
> it is not immune to errors<p>They’re pretty much part of the guardian’s dna:<p>> Frequent typographical errors during the age of manual typesetting led Private Eye magazine to dub the paper the "Grauniad" in the 1970s, a nickname still occasionally used by the editors for self-mockery
Hard? So is using the degree symbol apparently: not a single one in the whole article.<p>(68F is not a temperature — it’s a seat number.)<p><a href="https://degreeswhat.com/?68" rel="nofollow noreferrer">https://degreeswhat.com/?68</a>
Delta's like temperature are standard issue to resolve in globalization. Another fun one are complex units that are a combination of more base units like luminance (nits = candela / m*2 or mph.<p>I worked on a package to globalize a consumer-oriented fintech reporting product. With ESG reporting this has become increasingly important to get the unit conversions and Delta's right. You end up mapping the data source units to locale targets.<p>In Python, the Pint framework plus Babel locales are excellent.
As far as I can tell from googling, nobody ever says it’s “twice as hot” except as the figurative name for something or to say that it’s wrong to say “twice as hot”.
GPT-4 correctly converts the difference to 36F. GPT-3.5 on the other hand gets crazy and decides that the difference is 154.4F. Same prompt. At this point I'm starting to believe GPT3.5 is dangerously stupid.
The book Inventing Temperature by Hasok Chang is a wonderful account of how hard it has been to grapple with temperature scientifically.<p>My favorite anecdote is the scientist who carried arround and shook a bottle for two weeks to distill the water for experiments in finding when water boiled. When the water exploded after heating he found that not only did he not know when water boiled, but now he wasn't even sure what boiling was.
From a software engineering perspective, this shows that physical units are not a fool-proof typesystem, and you need alternative units (types) for differences.
Isn't ths following incorrect.... somehow? Something doesn't line up.<p>----<p>Reading the article I found this:<p>parts of Malawi saw a maximum temperature of 43C (109F), compared with an average of nearly 25C (77F)<p>As I expected the actual temperature increase was 32 °F, not 68 °F.<p>---<p>Except the error should have been 32 (which you go on to explain, because we add 32 to start a conversion) and the correct temp difference should have been 36 (20 * 1.8) which is shown later in the article.<p>I can see getting that wrong, but the actual temps quoted seems to correctly portray 32 opposed to 36 like we would expect.<p>Just rounding errors or some other oddness?
Looks like the Guardian have already amended the temperature differences in the article in question according to the footnote: <a href="https://www.theguardian.com/world/2023/oct/17/malawi-swelters-in-record-heat-with-temperatures-nearly-20c-above-average" rel="nofollow noreferrer">https://www.theguardian.com/world/2023/oct/17/malawi-swelter...</a>
A bit related, but I hate how many errors I get because I want my system language to be English instead of my native language (Norwegian) on my laptop, phone etc. Because I don't want a badly translated experience. However, I still want units in meters, Celsius, dates written sensibly, time in 24h format etc. But not all apps understand this, which is quite annoying. It's like they only look at the language and make a decision, even though on OS level there's more fine grained locale settings.