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This is why we should ditch Celsius for Kelvin. I never liked how we coupled 0 and 100 to where water freezes and boils under certain conditions. Kelvin doesn't
by artisinal 2mo ago
This is why we should ditch Celsius for Kelvin. I never liked how we coupled 0 and 100 to where water freezes and boils under certain conditions. Kelvin doesn't rely on non-invariant reference points.
- analog31 2mo agoI think that both the Celsius and Fahrenheit scales are now defined in terms of Kelvin and a formula. Most if not all of the units of measure are no longer related to their history except for an agreement to make the new units match the old ones at some point.
- 0cf8612b2e1e 2mo agoThe US is technically metric in that the units are defined in terms of the metric equivalent. A US inch is exactly 2.54cm.
- mikewarot 2mo agoYou can thank Carl Edvard Johansson[1] for that, the inventor of the gage block.[2] He was the one who decided to make it a convenient value, according to Wikipedia[3] As a result of the definitions above, the U.S. inch was effectively defined as 25.4000508 mm (with a reference temperature of 68 degrees Fahrenheit) and the UK inch at 25.399977 mm (with a reference temperature of 62 degrees Fahrenheit). When Carl Edvard Johansson started manufacturing gauge blocks in inch sizes in 1912, Johansson's compromise was to manufacture gauge blocks with a nominal size of 25.4mm, with a reference temperature of 20 degrees Celsius, accurate to within a few parts per million of both official definitions. Because Johansson's blocks were so popular, his blocks became the de facto standard for manufacturers internationally, with other manufacturers of gauge blocks following Johansson's definition by producing blocks designed to be equivalent to his. This makes it relatively easy to handle making metric threads on imperial machines, and vice versa, because you can use 50 / 127 gear tooth pairs to do the ratios. [1] https://en.wikipedia.org/wiki/Carl_Edvard_Johansson https://en.wikipedia.org/wiki/Carl_Edvard_Johansson [2] https://en.wikipedia.org/wiki/Gauge_block https://en.wikipedia.org/wiki/Gauge_block [3] https://en.wikipedia.org/wiki/Inch#History https://en.wikipedia.org/wiki/Inch#History
- analog31 2mo agoAn odd little factoid: A metalworking lathe will usually have a mechanism for cutting screw threads, with a multi-ratio gearbox for linking the rotation of the spindle to the motion of the carriage. For cutting metric threads, you have to change a pair of gears. So there will be a pair of gears with 50 and 127 teeth, which produces the 2.54 ratio. Then you have to look up the correct gearbox settings for each metric thread pitch in the manual. [0] It's a big royal pain in the arse, and I've never had a machinist agree to turn metric threads on a lathe. They would rather wait a day and order a metric tap or die. Nowadays the CNC lathes just do it auto-magically. Also, among old bicycles, there are some weird national thread standards that had metric diameters but inch thread pitches, because of machinery imported into countries like Italy and France during reconstruction after WWII. [0] Edit: Just noticed duplicate comment preceding mine.
- xgulfie 2mo agoKelvin does still rely on each degree being 1% of the way between freezing and boiling so it kinda does rely on a variant reference point
- chermi 2mo agoThe reference point is the triple point, and invariant.
- xgulfie 2mo agoSure technically yes, but also celsius is now technically defined as just Kelvin plus 273.15. Degrees have technically been redefined as exactly 1.380649×10^−23 joules
- chermi 2mo agoWhy is that only "technically yes"? It's precisely how the thermodynamic and empirical temperature scales are matched.
- NooneAtAll3 2mo agotripple point of what tho? which water?
- chermi 2mo agoWut? Water. H20.
- Guvante 2mo agoYou want numbers to be understandable and K produces illogical numbers. (There is a reason it is common to drop the century when talking about years, humans are less skilled at numbers over 100) And I know temperatures in Fahrenheit go higher but it is common to refer to Phoenix as "over 100" even when it's high can peak over 120.
- zinckiwi 2mo agoThat’s 02025 thinking.
- GolfPopper 2mo agoX̅ ? (I'm a little sad the five-digit date hasn't become popular.)
- chrismorgan 2mo agoWhy would five-digit years have become popular? They seem roundly a bad idea. Years aren’t even four digits by custom: they’re just numbers, with the present idiosyncrasy of eschewing a grouping (thousands) separator. We say the sack of Rome was in 410, not 0410. Only for specific serialisation purposes have we ever recorded fixed-width dates, acknowledging that there are limits to this. The recording of two-digit or offset-by-1900 years in computer systems was a case of bad judgement. The recording of four-digit years as is presently customary is pragmatic and entirely adequate for the next few thousand years, and there’s no point in designing things beyond that horizon.
- lstodd 2mo agoYou mean 0o2025 that is 1045AD?
- thaumasiotes 2mo ago> (There is a reason it is common to drop the century when talking about years, Yep. > humans are less skilled at numbers over 100) No, the reason is that the century is constant and therefore carries no information. Where the century isn't constant, it never gets dropped.
- warmdarksea 2mo agothis is actually why i like fahrenheit the most... 0F is "really cold" and 100F is "really hot", whereas in celsius 0C is "kind of cold" and 100C is "uninhabitable". it makes sense for the 0-100 range to be reserved for temperatures frequently encountered in our habitat as humans i think...
- ajmurmann 2mo agoThis makes sense if weather is the main focus. For things like cooking Celsius is great though.
- 0cf8612b2e1e 2mo agoI am failing to understand why there would be a distinction. They all seem arbitrary set points you learn. 450F vs 230C does not feel like anything gets easier there. Maybe in some highly technical baking there are some nice deltas that appear?
- clickety_clack 2mo agoAren’t you just remembering specific numbers though? Unless you’re trying to boil water unseen so that you can only see a thermometer, the specific 100°C mark isn't that useful.
- kelnos 2mo ago> Aren’t you just remembering specific numbers though? That's the thing about this. It's so tiring for people to argue which temperature scale is "better". Nothing is better or worse. What's "better" is individual, and is just "what you grew up with". Because right, you're just remembering specific numbers, and remembering how those temperatures feel. (Or in the case of cooking, remembering what those temperatures do to your food.) > Unless you’re trying to boil water unseen so that you can only see a thermometer, the specific 100°C mark isn't that useful. Even then it's not that useful, as water doesn't really boil the way most people think it does. (And god forbid you aren't at sea level and aren't at standard temperature and pressure.)
- 2mo ago
- throwatdem12311 2mo agoNow do metric vs imperial.
- artisinal 2mo agoNothing screams freedom more than using ancient terms like horsepower and measuring tires in inches and percentages. The other day I heard an American talk about a TV being 65 inches. Took me a while to understand they had a 165 centimeter diagonal television.
- alehlopeh 2mo agoSurely you mean tyres? It’s all arbitrary. Get over yourself.
- clickety_clack 2mo agoI bet you’d use lightyears over petametres or exametres though.
- tancop 2mo agomost tv makers and electronics stores in europe give you the screen size in inches first and cm second. they only come in a few common sizes so the specific units dont really matter.
- vel0city 2mo agoSpeaking of tires, its actually a crazy mixture of units here in the US. You might have a size like P215/65R15 which translates to a radial passenger tire of a 15" rim, 215mm wide tread (sidewall to sidewall), and an aspect ratio of 65 which is a ratio of the sidewall to tread width. So a tire size is expressed in inches, millimeters, and ratios.
- fps-hero 2mo agoStrange statement to say in an article specifically about water, of which both the Kelvin and Celsius derive their scale.
- NooneAtAll3 2mo agokelvin still has reference points - absolute zero and tripple point of water good luck choosing which water, tho