I’ve learned about them in school, but I’ve never heard anyone say something is 8 decameters long or anything like that. I’m an American.
They are “technically correct” measurements since they are a valid prefix, and could be used if you wanted. but they are very infrequently used in any industry. Since most of the time measurements are better served by higher precision (just using Meters) or need no precision at all over long distance (switch to kilometers), no need for excess measurement types unless necessary
Bro skips right past centimetres.
Well he asked about deca and hectometers, which are all larger-than meters.
But the same kind of rules apply below the decimal point as above it. We have millimeters (0.001 extreme precision), centimeters (0.01 high precision), and meters (1 low-ish precision). Decimeters (0.1) exist but are rarely used since both meters and centimeters can get the same result. Micro meters and nanometers are also used more frequently, but it becomes industry specific when actually doing things that small.
Valid, but rarely used, as it’s usually just as fast to say “two hundred meters” instead of “two hecto meters”.
However, those prefixes have other (non-SI) uses. A hectare is common way of referring to a 100x100 meter area. And a decare is 10 ares, i.e. 0.1 hectare.
Also: hectopascals.
To be fair, once all the boomers are gone we’re probably going to go full kPa.
Meh, who knows. The change from millibars was quite a while ago.
Right, forgot about that one.
For distance, no. Day to day we use mm, cm, m and km. But in more specialised settings (e.g. construction) I’ve seen sometimes decameters.
For weight yes, grams, hectograms, kg, tons. Liquids is usually ml, cl, liters, hectoliters (not sure it’s spelt that way).
In labs I’ve also seen also micro and nano of all three units.
Use cubes for water. Short for cubic meter. That is 1 meter by 1 meter by 1 meter which is also exactly 1000 liters.
This is one of the convenient metric parameters where they made an easy conversion allowing you to precisely use distance to calculate volume.
No, some measurements just aren’t used, even when they’d be a good fit.
Like lengths. We never use anything above km. Even for things like space, we say “million km” rather than gigametre.
The closest we come to hectometre is hectare, which is used for land area.
I’d say we use every 3 prefixes, nanometerw, micrometers, mm, m, km, than any much higher than that usually uses space units (parsecs, AU, lightyears, etc.)
Megameters are sometimes used, that’s not true.
Who uses megametres? It’s not something I’ve ever heard in the UK.
A megameters is 1.000.000 meters.
Where do you live and what is your profession? I have heard anyone use megameter seriously.
Germany, studying Cybersecurity. They are used in astronomy through, only a hobby if me.
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We do have a perfectly good word for inch : duim (thumb)
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In France “hectare” (10 000m²) is used for fields and burning forest. Beside that deca or hectometers are never used
An hectare is 10.000 m2
And we use hectolitres for wine production
Mb it’s 100m*100m
Hectares are also standard in Australia
Nz too apart from old people who still use acres.
From my experience in Norway, these are typical in context of daily speech:
Weight (gram): tonne (a substitute name for Mg (Mega)), kg, hg, g, mg, μg (mostly in medicine)
Distance (meter): mil (10 km), km, m, dm (kinda rare), cm, mm
Volume (liter): l, dl, cl, ml
In my experience, the deca-predix is very rarely used. Most of the missing prefixes are just substituted for numbers, i.e. saying “a thousand kilometers” is much more common that “a megameter”. Of course, this differs depending on context, as a lot of the prefixes become more common within scientific fields where the sizes are common.
On a separate note, even the numbers can be a bit inconsistent. It has bothered me that it’s often common to say “a thousand milliard” instead of “one billion” (also note that we use the long scale).
In Germany Hectoliter is also used to calculate beer volume in commercial settings, like planning for a bar or a festival.
„Kommerziell“
μm and nm used in engineering and science fields fairly frequently
From my experience in Norway, these are typical in context of daily speech: (…) km, m, dm (kinda rare), cm, mm
Don’t forget the Scandinavian mile! You and the Swedes use it all the time.
It depends on the situation, sometimes they are really handy but most of the time we stick to kilo, centi and mili.
Where i live, Hecto (100x) is used, for example to measure distances and areas for big properties. 1 hectometro equalls 100 m, or 1 hectarea (hm^2) equals 10000 m^2.
Also, it is widely use for pressure, cause 1 atm is 1013 hPa
Decameters are used but for special situations, like quantifying natural gas consumption
in school in austria we teach dezimeter (tenth of a meter)
decimeter is a good measure because one cubic decimeter (1 dm³) equals one liter ( 1L )
*of water
1 cubic decimeter = 1 liter. Period.
No, you’re thinking of a kilogram. A liter and 1dm³ are identical.
Haha obviously, too early in the morning ;)
1dm^3
Ah jeez, thank you. Fixed it.
No, volume dimensions are independent of what a specific volume is filled with.
1 liter of water is 1 cubic decimeter of water just as 1 liter of air is 1 cubic decimeter of air.
Decimeter is used in older American botany books for some reason. Only place I’ve ever seen it
I’m American, but follow mostly Europeans and Canadians online and use metrics in my own head just because it makes more sense.
I gather that the deca-/deka- and hecto- (along with a few other) prefixes are similar to imperial furlongs, leagues, stones, barrels, kegs, and hogsheads: They exist, but no one uses them outside of very specialized circumstances.
Well, not exactly. Those imperial units are all a unique measurement that one would have to learn to use. The SI prefixes meanwhile are simply powers of 10. Deca means 10, hecto means 100, kilo means 1000. Decameter literally means 10 meter. And so people just end up saying that instead, because it’s easier and conventional. But in some situation where you’re frequently dealing with 10s of meters it might be easier to use decameters.
The system also provides prefixes for extremely large or extremely small units. You’ll be hard pressed to find anyone referring to a ronnameter (10^27 meter). But it’s there if you ever need it, because it’s again just a power of 10. While megameter (1000km) is pretty much never used, megahertz is very common. SI simply provides a unified system and we can apply it in whatever way is most practical.
“Similar” = “not exactly”
Your point?
I think the point op is making is with ‘stones’ or ‘furlongs’ etc you need to already know what that unit represents to make sense of it.
With metric units, even the infrequently used increments can be reasoned out just from the name of the unit, as it’s a standard prefix in fixed multiples of 10, not a random number that must be learnt.
So they’re neither similar or exactly the same in principle really.
In fairness, you also need to already know what grams, meters, and seconds represent. And the prefixes are hardly self-explanatory. You’d still have to look up the unfamiliar ones. Just like you have to look up nautical miles or knots.
Well with metric there are alot less words you need to know to use them I think is the point of difference.
Like you need to know that a stone represents a weight, and that that weight is 14 pounds. What’s a pound? Oh it’s 12 ounces. None of those words are the same out of context but all describe a weight and the size of the weight.
In metric you only need to know that grams measure weight, metres length, litres volume. Then everyday use is normal prefix increments like OP said.
And again the prefixes apply consistently across units too, so a millimetre, a millilitre or a milligram will all be the same fraction of their base.
It seems that we’re both fans of SI units. I’m not arguing against metrics. But you still have to know what the words mean, and to do that, you have to look them up. You can also look up deebles if necessary.
And not to pick nits, but grams measure mass, not weight. Weight is newtons. A pound is 16 ounces, not 12. A lot of the measures, such as weights and volumes, use powers of two: 2, 4, 8, 16, 32, 63, 128.
It’s easy to get imperials confused. That’s why I’d rather call a pound about a half kilo in my head and be done with it.
Haha, I promise I didn’t intentionally make my point about how obscure imperial units are in conversion. I looked it up but clearly transcribed wrong!
Sweden uses decimeters and deciliters
And hectograms. We just shorten it to ”hekto” though. It’s how we buy stuff from the deli. ”2 hekto salami please”.
The silly Austrians would ask for “20 Deka Salami, bitte.” It’s weird.
Sweden also uses mil for distance, which is 10^4 meters (10 km)
Sweden is also the only country in the world to have a sensible use of the word ‘miles’ (or ‘mil’ in Swedish):
10km = 1 mil
They use this a lot when speaking of travel distances longer than 20km.
In Canada anything over 20km is referenced as time. “it’s about an hour drive”
In America, I’ve seen nurses and diabetics use deciliters in reference to medication or concentration before.
Deciliters are not infrequently used in recipes here as well. I’ve never seen decameters or hectometers used by anyone.
In Italy we use hectograms (“ettogrammi”, “etti” for short) in day to day life when buying groceries. You don’t ask for 200 grams of ham, you just ask for 2 etti.
Thinking how I always order deli meat in units of 100 grams, feels dumb we don’t do that in Canada too
Yeah I don’t think it’s very common elsewhere. Right over the border with France they were already saying “200 grams de jambon”.
But I think it’s convenient. Small number make brain hurt less, brain no need to think.
In Romania we use them for measuring areas. An “ar” is 100m^2 or a square decameter, and a hectare is a 10000m^2 or a square hectometer.
In Germany we only use hectare. Ar is something you learn in school and never use.
Yes, they are used, but typically in specialized applications which is why you don’t see them every day.
