[SenorKimchi]

Thanks. I am usually not super pedantic but I've noticed some people using "mt" for meters recently. I immediately fall into confusion when the wrong symbols are used. Then go down the rabbit hole of trying to figure out if it is a cultural or regional thing.

[delta_p_delta_x]

People have used all sorts of abbreviations for the SI prefixes and SI units for as long as I can remember. I want to ask—are people not taught this in school? I had multiple introductions and revisions of the SI units and SI prefixes in secondary school, pre-university, and university, and every time, a wrong prefix or a wrong symbol was penalised by half a mark per question. I had classmates who mixed them up regularly and lost something like seven marks each time. They learnt very quickly not to, as those seven marks could make one or two grades' difference.

As someone who champions sole use of the SI units, this annoys me to no end.

I've seen things like 'kgs', 'gm', 'gms', 'mtr', 'mt', 'K' instead of 'k' (note capitals) for 'kilo-', mixing 'm' and 'M' (which are supposed to mean 'milli-' and 'mega-' respectively), usage of 'u' instead of 'μ' for 'micro-' (the one exception I will concede is 'mc' in the medical field, because people apparently confused 'μ' and 'm' which results in a 1000× over/underdose), and don't bother with the degree symbol (Alt+numpad 0176 on Windows, Option-Shift-8 on macOS) for °C, or use °K for kelvins (there is no degree, as it is an absolute scale and not relative to anything else, unlike the Celsius/centigrade and Fahrenheit scales), and so many other typographical errors.

[nayuki]

https://www.nayuki.io/page/common-mistakes-when-using-the-me...

[alexthehurst]

> are people not taught this in school?

I agree about standardization, but I think this framing comes off as lacking empathy. Plenty of folks either

- Avoided the topic in school or put all their effort into other subjects

- Didn’t learn this in school—there are a wide variety of education systems across all the decades and distances that folks on this site may have grown up in

- Learned this in school, but a lifetime ago, and haven’t had a reason to revisit it. At a certain distance, your life experience and work experience massively overshadow what you learned in school.

Forgive the inference, but based on your recall of specific grading policies I would guess that your time in school is still near to you, or at least very important. It’s not that way for everyone.

(I am of course doggedly accurate with my unit abbreviations.)

[edit: list formatting]

[hilbert42]

"People have used all sorts of abbreviations for the SI prefixes and SI units for as long as I can remember."

In the US that is, not in metric counties that use SI by default.

For those in the US (and to a lesser extent the UK) there are multiple metric systems. The other notable system that's still in use is the cgs (centimetre–gram–second) system.

'cgs units' are still used in some areas notably physics as they can make calculations easier, there they're called Gaussian-cgs units.

Incidentally, often, as here, 'cgs' is in lowercase to reflect the case of the units' abbreviations. That said, the uppercase abbreviation is also often used. For instance, as I typed this my browser kept correcting the lowercase to 'CGS'.

[umanwizard]

Honorable mention for "cc", which stands for "cubic centimeter" which is exactly equal to 1 ml. I can't find any logic to explain why cc is used in some contexts and ml in others.