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Common mistakes when using the metric system

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Re: Common mistakes when using the metric system

#41

Post by creata »

tkgally wrote: post #32

I thought this looked like good advice until I got to: > Mass/weight distinction > Incorrect: He weighs 70 kg; Correct: His mass is 70 kg > Incorrect: She weighs 50 kg; Correct: She weighs 490 N on Earth Really?! We’re not supposed to use kilograms to describe a person’s weight? And to describe someone’s weight, we have to use newtons and specify what planet they’re on? Good luck enforcing those rules.

Yeah, this is the only one that seems flat out wrong. When I'm on a bridge, I absolutely want to see "The bridge can hold up 3000 kg", NOT "The bridge can hold up 29 kN". Partly because "holding up" (as opposed to, say, withstanding) force sounds nonsensical, but primarily because knowing the maximum load in kg is much more useful.

Re: Common mistakes when using the metric system

#42

Post by n_plus_1_acc »

Tor3 wrote: post #31

The most common error I see is "kph" which doesn't even have any possible meaning. 'kilos per hour' would in most places be taken as "kilograms per hour". As in "my weight increases by 3 kph when I visit McDonalds"

I only see this from english speaking people who are used to mph

Re: Common mistakes when using the metric system

#43

Post by Mashimo »

PinguTS wrote: post #39
setopt wrote: post #17

Earlier quoted context omitted.

Note: The official SI unit “liter” was written “l” until a couple of decades ago, when they changed it to “L” due to frequent legibility issues (l/I/1). Some old texts use the old convention.

Changed? I never have seen the captial L for liter anywhere from daily use to scientific papers. It is always used in small caps.

After I read your comment and went into the kitchen and the first thing I saw was a handsoap bottle what had "1 L" written on it. Weirdly the milk had "1 ltr" on it :S

Re: Common mistakes when using the metric system

#44

Post by n_plus_1_acc »

LordHeini wrote: post #22
Hadarai5 wrote: post #3

I've never seen Mtr, sqm or gr. Even as a child, I knew the short of those unit names.

It is highly language dependent. In Germany you will sometimes see Qm for "Quadratmeter" (m²).

Mostly in lowercase, especially when talking about apartments or houses

Re: Common mistakes when using the metric system

#45

Post by SkiFire13 »

PinguTS wrote: post #35
xico wrote: post #30

> 1 KB = 1000 bytes But standard is kB, from kilo prefix.

Here it is either KB or KiB, depending on the meaning. IRC, KB is the only exception from the rule.

The SI standard is international and doesn't admit a K prefix, only k or Ki.

Re: Common mistakes when using the metric system

#46

Post by jeroenhd »

boxed wrote: post #21
ikari_pl wrote: post #14

I was surprised to see "L" as the "only correct" (though as minor mistake) abbreviation for a liter, being certain "l" or "ℓ" is the way to go, as that's how I was taught so far. Turns out that SI actually allows both "l" and "L", but I would only ever use the uppercase if it's a sans-serif font in a non-prefixed unit ("L" as opposed to "ml"). I've never seen any can or bottle using "mL" or "cL". Some of the examples…

I live in metric land (Sweden), and I have never seen "gr." for grams and honestly I would probably take a while to understand what it meant.

I've seen gr for grams. Not as common as just g, but it does get used every now and then.

Re: Common mistakes when using the metric system

#47

Post by dominicrose »

xico wrote: post #30

> 1 KB = 1000 bytes But standard is kB, from kilo prefix.

Right, the uppercase conventionally means 1024 so it should be kB or ko for 1000. There are some odd rules, like L for liter because of readability or some other reason. I've also learned in (French) school that we shouldn't use kL, that it doesn't exist. It does exist, but we apparently don't want to use it and use hL instead. Some people thing it's a linear unit and not a cubic unit. We count liters like we count potatoes and we use m3 for volume math.

Re: Common mistakes when using the metric system

#48

Post by isoprophlex »

eNV25 wrote: post #34

A IB Diploma Physics textbook I had used a negative one exponent instead of a division symbol in units. This is not normal right?

After taking Dimensional Analysis in undergrad I never stopped doing that, quite possibly to the nuisance of everyone around me...

Re: Common mistakes when using the metric system

#49

Post by d1sxeyes »

ikari_pl wrote: post #14

I was surprised to see "L" as the "only correct" (though as minor mistake) abbreviation for a liter, being certain "l" or "ℓ" is the way to go, as that's how I was taught so far. Turns out that SI actually allows both "l" and "L", but I would only ever use the uppercase if it's a sans-serif font in a non-prefixed unit ("L" as opposed to "ml"). I've never seen any can or bottle using "mL" or "cL". Some of the examples…

On the capital L for litre, that’s a suggested rule (second table), not mandatory.

I also agree though, there are things there which are decidedly not mistakes (e.g. “mcg”, which is most commonly used to avoid confusion between a sloppily written mu and a sloppily written m. I’ve seen this most commonly in handwriting by doctors and vets)

Re: Common mistakes when using the metric system

#50

Post by qwery »

Tor3 wrote: post #31

The most common error I see is "kph" which doesn't even have any possible meaning. 'kilos per hour' would in most places be taken as "kilograms per hour". As in "my weight increases by 3 kph when I visit McDonalds"

Not defending 'kph' exactly, but I can see how some native metric speakers (in Australia at least) might arrive at that solution on their own. You're right about 'kilos per hour': 'kilos' will always be taken to mean kg. But in speech, 'kays' is a common abbreviation for both km and km/h (confusingly). So 'kph' would be an ambiguous way of writing 'kays per hour'. I have heard a small number of people say K.P.H. as an initialism.

kays (distance) e.g. "Thongs'll do, we're only walking a few kays down the road."

kays (speed) e.g. "Apparently he was doing 120 kays in the Barina. I'll miss him."

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