I was surprised during NASA's first commentary session of the WEBB telescope launch. It seemed like it was the first time when they were consistently using SI units while speaking to their US audience. I think one time an imperial unit slipped out, but it got corrected immediately.
Imperial units are often tied to measurement devices or operations of a device, than just being a collection of odd standards.
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.
You mentioned nautical miles. Originally, the nautical mile was defined as 1/60th of a degree of longitude (aka one minute) along the surface of the sea, and so it is a pretty natural unit from a navigational standpoint.
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.
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
Originally, a meter was defined as 1/10,000,000 of the distance between the equator and the North Pole. The circumference of the earth is now 40,075.017 km instead of 40,000 km but it was a pretty good estimate for 1795.
I don't see why you are being downvoted, you are absolutely right. For example you have US Gallons and Imperial Gallons, with the Imperial ones being used in UK not US.
Yep, and those two gallons aren't even remotely close. It's the most annoying thing on car forums, because someone will always say "oh my car gets 30mpg but everyone here says they are getting 40mpg!"
Like, yes, because you haven't established whether they mean US MPG or Imperial MPG.
YES! I always assume ( and very stupid of me ) that it was some regulation with cars and the way they drive between US and UK making some difference in MPG. I never knew the G in mpg was different!
This is one of the illustration with online or even real world discussions where we argue pass each other under the wrong basic assumption.
I didn't seem that way for their online tracker. Every time you visited the website you have to manual switch it back to SI units as the default was not SI.
It's so annoying. They have the screen real-estate to show both units, but for some reason it's like they're trying make a very subtle statement to their international audience. "For Americans only" or something like that.
I can't believe that there were people who actively worked on killing this effort and actually succeeded. Talk about stupidly reactionary.
In general it seems US public policy has suffered since the 70s. There were things like serious efforts for universal health care or metric conversion. These days it's not even imaginable to make a big change in the country.
> 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).
Immigration from Latin America and Asia are certainly helping SI in the US. However, there is a loooooong way ahead... And forget about Celsius, this one is nowhere to be seen.
(US here). It kind of helps to think of celsius between 0-100 as “percent of boiling water” for me. Living in one of the hotter parts of the world at the time, being able to say the temperature is 40-50% of the way to boiling water really seems a good objective definition of “too hot.”
Technically 0F is the freezing point of water, just a different type of water.
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.
"Several accounts of how he originally defined his scale exist, but the original paper suggests the lower defining point, 0 °F, was established as the freezing temperature of a solution of brine made from a mixture of water, ice, and ammonium chloride (a salt)."
It's funny to use that rationalization regarding 0-100 when in reality the rest of the Imperial system is utterly allergic to that sort of scale. 0F and 100F being endpoints for "reasonable" seems a bit of a stretch as well. As a Canadian that's "reasonably cold" and "way too warm".
