But - out of curiosity - why is the soda can measured in ml and not in fl oz?
A passenger jet can attempt a landing on a 3000 feet long runway from 4 nautical miles from touchdown point, flying 250 knots at 1500 feet. Altimeters must be calibrated to announced local atmospheric pressure, or the default to 29.92 inHg or 1013 hPa.
Autoclave is a device used for sterilization that exploits saturated(pressure equal to ambient) steam. It is usually ran for 15 minutes at 121C(250F). According to a random internet source[1], atmospheric pressure at sea level is around 15 psi, and 250F is the point where pressure of steam exceeds that, being a function of temperature.
(One of) the beauty of SI units is measurement devices itself are universally built and marked in SI units that disparate measurements across industries can be converted and compared against. There is no “3000 feet runway 4 miles away” in metric, it’s a 1km runway 6.5km away. There is no need to convert between inHg and feet and PSI, or lb-ft and inch-pounds just because F.G. Superman in 1337 who pioneered art of bicycle repairing set measurement and tolerance for a bike frame to be 50 +/- 3.5 inch-yard per fortnight centigrade.
But that requires phenomena to be well studied and measurements clearly defined against SI units, which is a point more industries than we care to admit has reached.
That has to be an aspect of why imperial units persist, despite NASA and cutting edge aerospace are moving away from it, other than there would be a simple matter of gross widespread ignorance.
1: https://biology.stackexchange.com/questions/95722/why-do-we-...
It has since been redefined based on that original definition, as 1852 meters.
So it’s a goofy measure in that it uses base-60, but is otherwise more in the SI family both in terms of original derivation from natural measurements and in terms of its current SI-based definition.
https://en.m.wikipedia.org/wiki/Nautical_mile
There are other things out there called a “mile” that aren’t imperial, too. Take care when asking for directions in the Norwegian countryside, for example: https://en.m.wikipedia.org/wiki/Scandinavian_mile
Like, yes, because you haven't established whether they mean US MPG or Imperial MPG.
This is one of the illustration with online or even real world discussions where we argue pass each other under the wrong basic assumption.
https://en.wikipedia.org/wiki/Metre_Convention
> The Metre Convention (French: Convention du Mètre), also known as the Treaty of the Metre,[1] is an international treaty that was signed in Paris on 20 May 1875 by representatives of 17 nations (Argentina, Austria-Hungary, Belgium, Brazil, Denmark, France, Germany, Italy, Peru, Portugal, Russia, Spain, Sweden and Norway, Switzerland, Ottoman Empire, United States of America, and Venezuela).
As a European I find Fahrenheit kind of makes sense on a human scale as 0 and 100 are the upper and lower limits of it being reasonable to be outside. Below 0 is "too cold", above 100 is "too warm" and when it is 50 it is neither warm or cold.
That said, I think the US car industry has moved to metric and it is great to not need multiple sets of everything.
If we have 2mm of rain in Copenhagen this afternoon, and my yard measures 8m×12m, how much water must drain away?
2mm × 8000mm × 12000mm = 192 000 000mm³
= 192 000cm³
= 192 dm³ = 192 L
= 0.192 m³
2mm × 180km² = 0.002 m × 180 000 000 m²
= 360 000 m³
approx. = 360 000 tonnes.What about if it isn't water you are calculating but some other substance? You use a look up table to find the factors - we need to look up a but more in the table, but it isn't a big deal.
I always hear that argument about "but when will I need it?" If you're using this system then you're always going to use it. It comes up all the time, it's natural so you don't think about it too much.
Does it mean it's better? Well yes, but it doesn't mean other measuring systems aren't good. You don't need it, but you'll want it once you learn it.
The second is obviously relevant for the people responsible for rivers, storm drains, sewers, dams, hydropower and so on. When we start terraforming Venus, we'll need to add the conversion factor for sulphuric acid rain.
> my yard measures 8m
You use a very long unit of measure.
Sure I can do the math to calculate it in my head and take a few seconds.
How many meters are in 240cm? Don't need to 'calculate' it the same method. I just move the decimal over. 2.4m...
I say this as an American who finds our use of Imperial pointless. Infact, there is a highway in Arizona that uses metric instead of imperial, as it was a part of our move to metric. (The current measuring and weights system in the United States is based on Metric, we do use it, just converted into another measure)
Every time I need to add or subtract two measurements.
Quick:
What is 2' 3 5/8" plus or minus 1' 2 19/32"?
or
What is 701.7 mm plus or minus 370.7 mm?
Seriously I work with both everyday, and while I grew up with inches & feet and I still intuitively know how deep two feet of snow is better than 61 cm of snow, I'm really starting to hate the US measurements, and use metric whenever I can.
Also, whenever we deal with things from the rest of the world, it becomes a mashup of US and metric measurements.
The US almost converted to metric in the 1970s, but Nixon squashed it, basically on the complaints of what are surely the ancestors of modern US right wing know-nothings who didn't like "foreign" stuff.
Looking at it historically, the fractions made a lot of sense when things were more coarse, and the ability to split things into even sections, 1/2, 1/3, 1/4... was more common.
OTOH, Metric was designed for doing calculations - we already use the decimal system for all other math, so we should design a measuring system to use the same calculation system. It really does work better.
A few brake lines and some old exhaust bits might be SAE, but by and large vehicles are done with metric.
Personally I like that SAE has fewer sizes... Its frustrating as hell working on cars with a mixmatch of 6mm 7mm and 8mm bolts. oh this is a 15 but a few awkward 16s! Mostly though, cars are pretty standard. European cars seem to be basically - 7mm 8mm (hose clamps and other tiny stuff) 10mm (air filter housings and such where 8mm is to small) 12mm 13mm (misc bolts, intake manifolds, exhaust, almost everything) 15mm 17mm 19mm (these larger ones are basically suspension and other large components)
I'm all for metric or SI. But let's not overstate the value please.
>Two common definitions used today are the mechanical horsepower (or imperial horsepower), which is about 745.7 watts and the metric horsepower, which is approximately 735.5 watts.
I guess speaking as a Brit the foreigners just didn't have proper horses.
F*ck :D
After many years and different widths the smallest common unit of exchange evolved to be a power of two: 8 bits are a byte, not 9, 10, 27, 30, etc; though Unicode might have been better off if 32 bits were the base character. However then older systems would have been at least 75% less useful.
Physical addressing units are also binary, because literal address lines (or their virtually latched equivalents on a serial bit-shift register) are used.
ROM, RAM, and correspondingly non-volatile writable storage inherit this basic premise.
So a non-sales computer person speaking 'kilo' or 'mega' or any other SI unit in relation to a computer part means it will hold or be able to transfer at least that many SI units in the quoted units. Everything gets rounded to the nearest useful neighbor. A digital kilo is not 1000, it is 2^10. A digital mega is correspondingly also 2^20. This is very similar to the exponents in SI units.
For that matter, humans have 8 fingers and 2 thumbs. Wouldn't an octal numbering system make more sense? Though for that we'd have to come up with new unit names near 2^3, 2^6, 2^9, etc that don't sound silly.
Each of the 4 long fingers has 3 phalanges, so an interesting possibility is to use each thumb to count up to 12 on each hand. Given that many ancient units of measurement where base-12, I wonder why we didn't develop base-12 languages.
Wish we could all start understanding the difference between kilo and kibi, mega and mebu and so on for bits and bytes.
The advantage is not having to remember all those funny constants and being able to do math in your head that actually makes sense?
Or more important, to be able to write an article that the entire planet can just read without 95% of them (everybody outside the US, UK and Myanmar) having to resort to Google to find out if those numbers are impressive or not?
Just laugh at the joke.
This, very much! I've done a ton of physical simulation code in my life. Whenever some newb or student comes to me for the first time with their simulation code that mysteriously doesn't work, in 90% of cases they stupidly didn't stick to SI and forked up some unit conversion, or mutiple. I tell the to keep it in SI and never let me see them make that mistake again. (Only exception is simple 1-to-1 unit conversions of parameters and results, when some stupid interface definition demands it that can't easily be changed.)
For the last years I’ve mostly seen watts being used in NL, but it’s been ages since I saw a fast and furious movie or a top gear show. The car sellers use kW and often also, I assume metric, horsepower.
1. Everything uses a common base, so you don't get a base change on a scale change (or indeed, two different bases for different parts of the same measurement), and dimensional consistency becomes trivial.
2. The base is base-10, which is the same as our common counting system.
1. Temperature. It’s useful to elongate units over the range normally experienced by humans, which Fahrenheit does and Celsius does not, because it avoids tenths of a degree, for example, in room temperature selection.
2. Woodworking and similar: it’s useful to use powers of two because it’s very common to be marking/cutting/etc. 1/2 or 2x a value, which is easier to do in inverse power of two English measurements.
Outside of these weird exceptions, it's SI all the way. And this doesn't really vary with age. The web site whrere you buy wheels and TVs doesn't know your age so it will say the rims or screens are 20" regardless of who you are.
It's even more pronounced with camera sensors, the size given in fractions of an inch is some kind of "equivalent to", whereas the size in mm is the actual size. Apparently the image sensor inch is 16mm or something like that.
Beaufort is a dimensionless label as far as I'm aware and grit is used as such too (i.e. it never says anything else than "240" i.e. it doesn't "240 grit" or "240 something per inch").
My list wasn't close to exhaustive. We use all kinds of weird units.
Besides bar I sometimes see mmHg for pressure. Shoe sizes. I've never seen acceleration in m/s2 outside a physics problem, otherwise it's either G or seconds to 100 km/hr.
I'm aware. But I'd say its mostly used as a dimensionless. When I argue "we use metric except for these few" I mean in the cases where the unit (a length, mass, pressure etc) is actually uttered or written.
In some cases as you note there are labels which have non-metric definitions underneath, such as sand paper particles having a never-pronounced inch definition. The same goes for some weapon calibers where you might say a ".303 cartrige" for rifle ammunition but you'd never say a ".303 inch cartidge". A lot of people probably use these labels without knowing they are using an imperial definition. And that (I'm guessing) is also part of why it survived the metrification.
> I've never seen acceleration in m/s2 outside a physics problem, otherwise it's either G or seconds to 100 km/hr.
"10s to 100km/h" is as metric as m/s2 though (But again not pure SI). g being a constant obviously has no explicit unit, it's as metric as you want it to be :) I hear "5g" as 5x9.82m/s2 but an american probably hears something else.
This is all as it should, however a large number of people have a really hard time groking the difference between kW and kWh.
So much so that I wonder if we should start specifying battery capacity in MJ to help people clarify things in their heads.
It is the mixture of both that ends up being very confusing.
Where in Europe are you that anyone uses kW for engine power lol. Yes it's listed in kW on my registration document but I've literally never heard anyone using kilowatts to describe engine power instead of horsepower, and I lived in a few European countries so far.
complete shitshow.
In the German speaking world everyone knows what a hp is (PS), how much his car has, his past cars had, in which configurations their car is available... although the kW is what is printed on the documents since ages now.
Nobody likes change. Some people still complain about the Euro, and that the DM was so much better... At least it is not called ECU.
"The country where everything is bigger (*)"
(* except for consumer goods that would be designed around a practicable supply current of 10A elsewhere)
But seriously, I do like the split-phase power we have in the US. I think we get the best of both worlds, having lower voltages in most living spaces, and higher voltages reserved for high-power appliances.
How is this possibly a benefit for anything though. It's not like 110V is safer in any practical way, if you stick something in a socket it will kill you just as much as 220V would, so it seems like for literally no reason at all American homes have a much less "ability" to support a wide range of devices that work without any issue elsewhere in the world.
I've been shocked with 120v on bare skin multiple times.
Current code in US/Canada also requires RCDs (we call them GFCI) in some places (and AFCI everywhere, which the rest of the world hasn't really adopted) and shuttered outlets... but these do not catch all types of faults. For instance, if a human conducts electricity across two conductors connected to an RCD/GFCI, it won't trip. It only trips if current is drawn to ground or to another circuit. Layered safety is a good approach.
That's not to say that 240v systems are unsafe -- they just have different characteristics and requirements because of it.
This one is definitely changing. Lots of people here only know their weight in kg now (including me).
Is that with younger generations? Most people I know doesn't have clue about their weight in Kg.
The problem with switching the US to the metric system is that the cost would be truly massive. It would take decades, somewhere in the order of 50 years, for a complete conversion.
There's the obvious, things like every single highway sign would have to be replaced. And then there's everything else, like every single tool that everyone owns in this country would have to be replaced at some point. You would still have to be able to buy and use imperial unit hardware and tools for decades during and likely after the transition. I can't possibly list just how deep and wide such a conversion would have to reach.
And that's assuming everyone goes along for the ride. That said, a 50 year timeline would mean a new generation would grow up using the metric system. Another 25 years after that and we should be OK.
All of that said, the real problem is political. The cost of such a transition would be significant. Politicians will only get behind things they can convert into votes. Going metric isn't one of these things. Spending billions of dollars over five decades isn't something anyone can use to win an election. Most people aren't close enough to the design and manufacturing of goods to understand just how much this system actually hurts us. And so, going metric, in a practical sense, becomes an impossible dream.
It's not that great a motor design. It's good, but we had similar power to weight motors where I worked 10 years ago and could run 200kW for more than 20 seconds. Good motor designs are cool, but IMHO they are usually not news-worthy but are just marketing.
This said as a French and ex-physicist.
The article is written for an American magazine while the pictures are from Koenigsegg directly, which are European; beverages use ml and l to measure contents.
Take a look at the graph, also provided by Koenigsegg, it uses Nm and kW.
I was always tought that the liter was an SI unit, I mean, it's defined in terms of SI units, I know it's not a base unit, but weird that it's singled out as "well, you're technically SI compatible, and you're defined in SI units, but we're not gonna let you be part of the group" :)
It even has an official SI symbol (L), despite not being an SI unit, what?!
So satisfying...
Expressing quantities in SI units doesn't require 'base units'. SI prefixes are permitted (milli, micro, kilo, mega...), as are certain exclusions (including minutes, hours, ...).