The Metric Red Herring (2022)
chriswarbo.net
chriswarbo.net
For something like a home thermostat, 71F, 72F, and 73F can easily be destinguished by feel and represented as a 2 digit number. Doing the same in C means rounding and losing steps or forcing you to deal with decimals, which people generally avoid.
The ambient temperature is such a subjective thing, so many things affect it besides absolute temperature: wind, sunlight, humidity. And it changes so fast too. I don't think I even need the precision of Celsius, I don't get the necessity of twice the precision of Fahrenheit.
And sure, cmiller1, the reference points are arbitrary in Celsius, so are they in Fahrenheit. At least in Celsius the zero point could provide useful information: I know when it's slightly higher than 0˚C there would be mud, when lower — icy roads. (And it isn't really affected by the elevation — ~0.01˚C in the whole range of liveable pressures.) But that's, I believe, irrelevant: I have intuitive understanding of -17˚C or 37˚C without it being a round number, the same way you know what's 32˚F.
My room is considerably cooler than my kitchen, with a temperature difference of as much as 10 °C, especially when I am cooking multiple dishes. If I open my back door in said kitchen, then the temperature rapidly and noticeably plummets, even if several of the gas hobs are on.
You discuss 'precision', but then you don't take the next step of realising that any precision comes with a built-in uncertainty, and the 'human feel' of temperature has a massive uncertainty of as much as ±7 °C—depending on, as the other commenter said, wind, humidity, shade, and internal body temperature.
I've been raised entirely in a metric country, and have never used degrees Fahrenheit. It was a complete novelty for me when I was younger, and in many ways still is.
It is a matter of 'what is more intuitive'. Room temperature is 25 °C, human body temperature is 36 °C, a fever is about 38 °C, it is freezing outside when it is 0 °C or below, and water boils at 100 °C.
Also, living in a climate where winter temperatures often hover around the freezing point, you develop a healthy interest in it.
As an example: If it's been a few days below 0 C, and then it warms to 3 C, the snow on the sidewalks will have compressed to ice whose top layer will now melt and create absolutely lethal walking conditions.
Or if it freezes after having sleet conditions (0-4 C maybe), you get this craggy ice that's not as slippery but is uneven and thus a hazard in its own way. Also very miserable for bicycles.
Anders Celsius was a Swede. He knew.
But such conditions are rare and localized. When looking for extreme dew point values, I found this statement: "The highest dew point ever recorded was 35 °C, or 95 °F. This occurred on 8th July, 2003, in Dhahran, Saudi Arabia. This happened because the air temperature was 42 °C, or 108 °F, and the relative humidity was 68.5 %."
So tropical latitudes might care about temperature / dew point near those numbers, Northern Europe and friends spend their time worrying about freezing.
I assume your post is also sarcastic, or at least tongue-in-cheek.
Fahrenheit is the most insane unit ever created. It is a snapshot of two random temperatures that just happened to be lowest temp easily achieved in 1724, and human body temperature (not a constant LOL), which he perversely assigned 90, not 100.
Even acres seem to be derived from ploughing. I'm a farm boy, so I can relate to that, but I bet no city dweller has any vision of an acre in their mind's eye. Even a farm boy like me has trouble converting acres to sq. miles or sq. feet.
I remember metric from elementary school as well. English units were taught by: "Here's a ruler, go measure some things." Metric was taught as a bunch of conversions. The powers of ten were supposed to make it easy: "Metric is easy, it's just math."
Well, most people are repulsed by math.
My Canadian friend told me that he learned metric in school by: "Here's a ruler, go measure some things."
Today, most of US life is English, and most of industry is metric. A normal household doesn't need English wrenches, but does need metric allen wrenches if they've got bicycles.
> I don't like what I'm not used to.
Of course if he's using CNC or DROs primarily it's a lot less valid of a complaint.
I should think ~95% of us already do?
But even so... for dividing by 3, sure, the 12 inch -> 1 foot jump is neatly divisible. And obviously 3 feet -> 1 yard. But you don't get much help going smaller than an inch on any measuring tape or rule I've used. 1/2, 1/4, 1/8, 1/16... 3ish-mm inside of 10mm is no worse. Or dividing a cup into 3 equal amounts of ounces, or even a gallon into thirds. So I'm not sure there are many consistent, coherent features for all the random different scales for how things like liquids vs distances work. Heck, 10 feet, 100 feet, 1000 feet are all common enough things to hear, taking us back to powers of ten, because nobody bothers trying to stick with furlongs... (Which takes us exactly to the author's point about "just one unit" being a better way to do things, since at some points you do need to take your feet and your fractional amounts of miles and do some conversions that few people have quick practice at, vs "how many meters are in 1.25Km?")
I have a soft spot for Fahrenheit temperatures because they're more granular at human scale but most of the rest of the system is pretty junky and even the convenience of 1/2, 1/4, etc quickly gets lost when you're in the land of adding an 1/8th to a 1/16th and subtracting 3/4...
The advantage of metric is coherence and orthogonal dimensionality.
As a rough guide, if you're working in a wood | metal shop then just use millimeters (mm) for everthing and a third of a metre is 333 mm and a bit - how much you want to fuss on that depends on the required precision but honestly ... one third isn't the problem you're making it out to be.
Please convince me that adding 3/8" and 3/16" is easier than adding 9mm and 5mm.
Yes centifeet is almost as good as centimeters, but we don't USE centifeet! We use inches. and we don't use milliinches, we use 1/4s, 1/8ths and 1/16ths.
The problem is that the IMPERIAL units don't use powers of ten. They don't use any consistent base. There's a mix of 1/12ths, 1/5280ths, 1/32nds, etc. It's a total cluster fuck.
The whole article seems to just be some kind of troll bait...
Meters, liters, and even Celsius are fine. But Pascals are the hyperinflation of pressure units. 5 psi? That'll be eleventy million pascals. Maybe if I had a bike pump that had 50kPa increments alongside Psi, I could gradually figure it out.
And conveniently, the atmospheric pressure is very close to 100kPa. So you can use a derived unit called a "bar" which is 100kPa.
Your bike tires need to be at around 3 bar.
Yo, what? I'm pretty sure I do my bike tyres up to about 6.5 bar. And that's down from the 7 I used to use until I heard that lower pressure creates lower rolling resistance and is better.
Ah, I see. You likely have a road bike, I have a mountain bike.
- higher rolling resistance (energy to flex the tyre)
- softer ride (but don't go so low that stones or potholes pinch the rim)
- better grip (surface area in contact with the ground)
So go max pressure on a smooth dry road, but go softer in the wet, or on a rough road/mountain.
Similarly, the tread on the typre will also affect energy absorption. Go for smooth road bike tyres, or slick MTB tyres, on a smooth road, but obviously super gnarly for rough mountain trails.
In precision machining, you'll also hear "tenths" (one tenth of a thou or 0.0001").
Is there a standard 'cup' somewhere in the basement of the Library of Congress?
Nassim Taleb and others are right.
Imperial -- having been honed by people actually doing things with their hands and sensing things with their own senses -- is better.