Talk:SI prefix

From Wikipedia, the free encyclopedia

You have new messages (last change).

Contents

[edit] Proposed Extensions

I altered the OP's post stating, "Of these only the litre is still in ubiquous(sic) use." In my experience, what the OP defines as an "are" is known as a(n) "hectare", that being an area equal to 56,000m2[1] (100mx100m). This term is used VERY widely as a pseudo-SI alternative to "acre" when talking about land and must, I would think, qualify as being in "ubiquitous" use? Also according to Google[2], an "are" is 1/100th of a hectare, or 10m2. As a result of this supporting evidence, I also altered the relevant parts of the post to reflect these values.64.201.173.205 17:49, 21 March 2006 (UTC)

I'm not quite sure of where your figure of 56000 m2 comes from. It doesn't seem to have influenced anything in the article, so there's no harm done. Obviously 100 m x 100 m is 10000 m2 = 1 hectare. Yes, an "are" is an area of 100 m2, and is used in Spain for measuring the floor space of buildings.--King Hildebrand 16:50, 2 August 2006 (UTC)

[edit] Dumphrey

The article claims that a liter is sometimes "referred to as a 'dumphrey'". I couldn't verify that claim and removed it. AxelBoldt

[edit] Binary prefixes

The powers of two have a new SI standard, IINM. 210 bytes == 1 Kibibyte (1 KiB), 220 bits == 1 Mebibit (1 Mib), 230 bytes = 1 Gibibyte (1 GiB). -- Hari (2002-03-18)

See http://physics.nist.gov/cuu/Units/binary.html, for instance -- Hari (2002-03-18)

Could you add an explanation to that effect? Such as "KiB should be used instead of KB...". (It's not a SI standard however.) AxelBoldt

Does anyone have an objction to me moving most of the explanation of byte prefixes to Byte prefixes, and leaving just a short paragraph on it here & a link? -- Tarquin 14:45 Jan 12, 2003 (UTC)
I've renamed it to "Binary prefixes". It's used for anything based on the power of 2 (e.g., bits, words), not just bytes. -- Dwheeler 20:12 21 May 2003 (UTC)

In my opinion, the whole "Computing" section must go. It is entirely incorrect when using the rules of the SI. The SI does not define any special exceptions to do with computing, and this entry implying such is incorrect. It's fine if we move this to a new entry, but it must be very clear that such usage goes against the SI. --Eliasen 11:07, 28 Nov 2004 (UTC)

I agree. Remove the section and direct them to binary prefix. - Omegatron 22:36, Mar 3, 2005 (UTC)

A vote has been started on whether Wikipedia should use these prefixes all the time, only in highly technical contexts, or never. - Omegatron 14:56, July 12, 2005 (UTC)

[edit] "iso" prefix

I've just added this. Gritchka I have to say I've never seen 'iso' mentioned in this context. What's the authority for this?

I've never heard of it. My encyclopedia doesn't give it in the table of SI. Official reference such as http://physics.nist.gov/Pubs/SP811/sec04.html doesn't give it. The only link I have found on google about it seems contentious (Star Trek science). It's also faintly ludicrous -- a metre is a metre. What is the point of saying "isometre"? Just to clinch it, the official site http://www.bipm.fr/enus/3_SI/si-prefixes.html makes no mention of it. I think someone thought "isobar" was a prefix applied to "bar", whereas it's a line of constant value on a map. In short, I can't find any evidence of its existence, rather, I'm finding evidence of its non-existence. It's going. It's gone ;-) -- Tarquin 00:34 Sep 15, 2002 (UTC)

[edit] Subdividing these?

It's all very well with the prefixes given here, but what about for example organic chemistry? You require extra endings for 2, 3, 4, 5, 6... (Okay, so they start meth- eth- prop- but-, but that's not the point... think about silanes.) What are the prefixes for 1, 2, 3, 4, 5...?


I don't understand your question. There are only prefixes for powers of 10. The prefixes used for systematic chemical names have nothing to do with SI -- Tarquin 23:04, 2 Oct 2003 (UTC)

[edit] "Billiard", etc

Do the number names "billard", "trilliard", etc, really exist? "Milliard" is old-fashioned (possibly archaic) in UK usage although its cognates are current in some European languages. I have never seen "billiard", etc, listed in any printed dictionary, except as "billiards", which is a game similar to pool. The UK, as has been pointed out on the page, now tends to use "billion", etc, in the same way as they are used in the UK. Other European languages vary between the US system and the older UK system. Could someone point out an authoratitive reference that lists these terms? If not, could I suggest they are removed or marked as neologisms, for the nonce, rare, jokey, or something else? Thanks. -- Paul G 09:57, 12 Jan 2004 (UTC)

At least in Swedish, the series Miljon, Miljard, Biljon, Biljard etc. series is used.
Mark these old-fashioned possibly archaic words as neologisms, 'ay? You can't have it both ways. Yes, they do exist though, alas, rarely used in English these days. My vote would be to leave them in. The reason: the original naming system of numbers (what Wikipedia calls the long scale) is logical and therefore easier to understand especially for speakers of other European languages. Jimp 13Oct05

[edit] Nonna, Dogga, etc.

Is there any reason that Nonabyte and Doggabyte haven't been added to this list yet? I was going to add them myself, but I wanted to clarify that their British name would be "Thousand Quadrillion" and "Quintillion", and that their symbols would be 'N' and 'D'. Does anyone have any authoritative sources on these? -- DropDeadGorgias 17:16, 19 Feb 2004 (UTC)

Because they are not real SI prefixes? -- The Anome 06:00, 1 Apr 2004 (UTC)

To answer this question about Nona and Dogga, there have been various times in history when nonabyte existed as a Wikipedia article, but it always went onto the "votes for deletion" page. About 90% of all Wikipedians agree that it shouldn't have a Wikipedia article. 66.245.30.189 02:01, 1 Apr 2004 (UTC)

There is a place for Non-SI unit prefixes. Why not putthese there? Jimp 13Oct05

[edit] Prefixes for 10^27 and 10^30

The creator of the Names of large numbers article has a part that uses SI prefixes for part of it that goes past yotta for xenna and viki. 66.32.148.174 23:13, 3 Jun 2004 (UTC)

[edit] Prefix for 10^27??

I contacted the webmaster of bimp.org and they say that they will not confirm a prefix for 10^27 as of 2005. Any comments?? 66.245.95.15 16:29, 2 Jul 2004 (UTC)

Surely the entry for Bronto must be removed until such time as this is confirmed by SI / BIPM?
The BBC has just written an article mentioning Brontobyte [[3]] as 10^27, but, Googling, there seems to be few precedents - a Sybase article [[4]](which can't even spell yottabyte); a UCL article [[5]] which puts a Brontobyte at 1000 Eb = 10^21 = Zettabyte?? An American article [[6]] which thinks that Brontobyte = Petabyte = 10^15 - and none of these cite any de jure authority. Does anybody know the origin for this proposed term?? Given the ambiguity, surely it has to go? Ian Cairns 23:00, 20 Sep 2004 (UTC)

[edit] Bilion

According to billion and Fowler, 'billion' can mean both 10^9 and 10^12 in the UK. Best to not mention it in the table headers -- Tarquin 08:57, 21 Sep 2004 (UTC)

The 10^12 meaning is utterly obsolete in the whole English-speaking world. As this is the English Wikipedia, the "long scale" column should really be removed to prevent needless confusion. – Smyth 13:02, 27 Sep 2004 (UTC)

[edit] Bogus SI prefixes

The category Category:Bogus SI prefixes contains a whole bunch of stubs that look to me like they're unlikely to grow. Anyone object if I merge them all into Bogus SI prefix or something similar? Bryan 05:33, 14 Oct 2004 (UTC)

[edit] Mega

How popular of a belief is it that it is okay to use mega- as a numerical prefix for a million (as if it belonged in the regular Greek numerical prefixes article)?? It is not in there; its literal meaning is "great". 66.32.255.51 01:29, 31 Oct 2004 (UTC)

Never heard someone use it. Chemicals pentane, hexane, ...., mega-ane? No way, you'd call the latter simply polyethene. I can't think of a situation right now where it could be used. A numerical prefix suggests that it is exact (1,000,000 and not 1,000,002) which usually doesn't make much sense for big numbers. Han-Kwang (talk) 12:08, 16 Nov 2004 (UTC)
Megaton is used for an explosion equivalent to 1 million tons of TNT. Is this an example of what you mea, or have I got hold of the wrong end of the stick?--King Hildebrand 15:41, 2 August 2006 (UTC)

What about a Megalith - just a big rock not a million of anything! (Chris Neale)

[edit] cc

Do doctors in American medical soap operas always say "cc" (short for "cubic centimetre") to mean "millilitre" because they don't want the audience to know they're using a metric unit? At least here in Finland, "millilitre" is a much more widely known unit than "cubic centimetre", even though they're the same thing. — JIP | Talk 17:17, 1 May 2005 (UTC)

No, all doctors in America use cc. Cburnett 17:25, May 1, 2005 (UTC)
Why do they call it cc instead of millilitres, then? — JIP | Talk 18:52, 1 May 2005 (UTC)
I wouldn't tak that as an established fact based on one person's comments. For example, what specific context do you have in mind? Liquid drugs are usually labeled in milliliters, and so prescribed. What's used for capacity of syringes? For cranial capacity? The more prevalant usage can be different in different contexts.
You are probably just a kid who doesn't remember the days when we had to learn that milliliters and cubic centimeters are different units. Some of the usage habits today go back to those days when a distinction was sometimes made for clarity, even though very few measurements were ever precise enough to tell he difference. That's just one of the factors that come into play--but fooling the audience into thinking they are not using a metric units is one of the least plausible factors. Your theory doesn't hold any water. Americans know that it is a metric unit, whether it is "cc" or "cm³" or "mL". Gene Nygaard 19:23, 1 May 2005 (UTC)
Actually, I've even seen liquid drugs measured in miligrams. In particular, morphine. Measuring liquids in cc's and solids in mg's are probably the most prevalent. I've *never* had a prescription filled in grains or ounces. :) But whatever is used and why, it has little to do with "fooling the audience". Cburnett 22:46, May 1, 2005 (UTC)
If close to 30 years is "just a kid" to you, then I agree. But no, I don't remember ever learning that cubic centimetres and millilitres are any different. — JIP | Talk 04:27, 2 May 2005 (UTC)
From 1901 until 1964, 1 ml was approximately 1.000028 cm³. The liter was then defined as the volume of one kilogram of water at its maximum density, rather than as a cubic decimeter.Gene Nygaard 04:40, 2 May 2005 (UTC)
Figures, seeing as I wasn't born in 1964. My parents hadn't even met each other then. The bit about fooling the audience was pure speculation on my part. — JIP | Talk 14:48, 3 May 2005 (UTC)

An old man such as myself remembers that many of our American textbooks of the late 1940 to pre-1970 era distinguished them as: cc = volume, ml = capacity (the latter being contingent on positive, neutral or negative meniscus formation of liquids). I hope this is some help; Dr.R.E.Petrere

[edit] Non-standard prefix abbreviations?

What about non-standard abbreviations, such as "mc" or "u" for "micro"? --Carnildo 17:41, 20 Jun 2005 (UTC)

That's talked about at micro.
Lee S. Svoboda 20:25, 7 October 2005 (UTC)

[edit] Merge with SI#SI prefixes

Shouldn't this be merged with SI#SI prefixes? They seem to have very similar contents.

Lee S. Svoboda 20:28, 7 October 2005 (UTC)

Yes, SI#SI prefixes should be moved here. The article SI is far too large as it is. Moving the bulk of SI#SI prefixes here would help make SI a more manageable size. Jimp 13Oct05
It's done. Jimp 14Oct05

[edit] History of the SI prefixs?

Does anyone have solid information on when the various SI prefixes were first introduced? I am under the impression that prefixes through mega/micro go back to the beginning of the Metric system, tera, giga, nano and pico go back to the intro of SI in 1960 (though they must have been discussed earlier) and the rest are newer (1980s??) . But it would be interesting to pin down dates and maybe add them to the table in the article. --agr 21:46, 18 December 2005 (UTC)

I'd love to know this, too. "Many SI prefixes predate the introduction of the SI in 1960." How far? — Omegatron 15:00, 24 February 2006 (UTC)

[edit] Kilo

This term for 10^3 (1000) has existed since Greek has diverged from other Indo-European languages. The way Greek words normally come into English would have it be chilia, and the reason for the kilo spelling is unknown; I think it is disputed whether it is because ch can be pronounced differently by different languages, or whether they had centi- and didn't want the letter c to be ambiguous.

[edit] Mega

This term, I think, was coined in 1874 by someone who thought an SI prefix was needed for 10^6. They knew Greek didn't have a word for a million, so they just decided to coin a term coming from a word meaning "great".

[edit] Giga and Tera

These terms were coined by extrapolating mega for great by including giga- for giant and tera- for monster, both from Greek.

[edit] Peta and Exa (the ones I think are absurd)

These terms are the ones I think are absurd because of how they originated. Do you hear stories like these??

Let's make up 3 characters named George Washinton, Thomas Jeffeson, and Benjamin Franlin. We made up these characters' names by taking names of famous people and dropping one letter out.

Then, a forger who stumbles across the story with the names falsifies the names by adding in the letter dropped out.

The people who coined these prefixes in 1975 must not have been thinking of these, but because this is how these prefixes came into existence, I regard them to be absurd!

This looks like a fascinating explanation, but I suspect it needs a bit of clarification. I, personally, can't see any link at all between the story and the prefixes. Sorry to be dim, and all that! Could someone (possible the original anonymous poster) please explain a little more fully? Many thanks. --King Hildebrand 13:53, 2 August 2006 (UTC)
Sorry - I think Georgia Guy's signature applies to the whole section. I'll go and ask him... --King Hildebrand 13:54, 2 August 2006 (UTC)

[edit] Zetta and Yotta

These were the start of a sequence in descending alphabetical order all SI prefixes from this onward are expected to follow. Georgia guy 00:13, 1 May 2006 (UTC)

[edit] And one other thing to say

  • The next preifx, starting with X, whether xona- or xena-, how should the X be pronounced?? Georgia guy 00:34, 1 May 2006 (UTC)

[edit] Myriad

Myriad

You should include the myriad prefix (abbr. is unknown to me)even if it is disambuigated. You should also note that the term now means "a lot," "many," and/or/any combonation of/with "much." I cant find much info. on it but maybe you/othres can.


This is already noted as myria- and/or myio-......

I have also found myria- as prefix for meter (in Hungarian: miriaméter) in a Hungarian law from 1874, which implemented the SI in Hungary. Since this law implemented international standard, myria must have been an official SI standard then.Timur lenk 00:43, 24 September 2006 (UTC)

I think you are confusing the metric system with the International System of Units, which is symbolized "SI" in every language. SI was developed in 1960, and one of the goals was to discard obsolete, redundant, and ill-considered units. Myria- was discarded at that time. It's metric, but it's not SI. --Gerry Ashton 04:30, 25 February 2007 (UTC)

[edit] I dont know (Jiwe-)

Is it true that they used to have a unit called Jiwe-, I dont think so but it could be true. I think it was meant to be 1x10^3+.21/K (of same base unit)-13% of one uL. Quite complicated, huh.... I can see why they dropped it if it was evre used....

[edit] non-SI scales

"The reason various fields have develop their own non-SI scales is because of the problems posed by calculating very large or very small numbers on a computer accurately and efficiently. 1 angstrom is a lot easier for a computer to use in calculations than 1 × 10-10meter as truncation errors and rounding errors can occur losing accuracy in the calculation."

Speaking as a programmer, this is nonsense. Computers are very good at this sort of thing, and would work in floating point which would have no such limitations in the ranges spoken of. Also, the use of scaled units predates the wide use of computers, and may well be more historical than anything else. They may be inconvenient for people to work with, but that's a separate thing. I will remove this section. Notinasnaid 10:03, 1 June 2006 (UTC)

[edit] Giga pronounciation

[ˈgɪgə] and [ˈdʒɪgə]. The former is more common than the latter. How do you know this?Seforadev 03:55, 20 June 2006 (UTC)

Personal experience lends credence to the opinion in the article. I have been moving in scientific circles for forty or more years, and have very rarely heard the soft form, [ˈdʒɪgə], used. --King Hildebrand 13:44, 2 August 2006 (UTC)

[edit] Micron

The term "micron" is, I believe, non-standard. The SI prefers "micrometre". Thus "millimicron", given as an unapproved usage of combined prefixes is not a good example. After all, if you remove the prefixes you are left with nothing but the letter N! Micron, along with thou (one thousandth of an inch) are used familiarly by engineers, and are not part of SI. --King Hildebrand 13:39, 2 August 2006 (UTC)

[edit] Abbreviations D and H

When I was a kid, and first learned of these prefixes and abbreviations, I was taught that the correct abbreviations were D for deka, to distinguish it from deci, and H for hecto. The exception, I was taught, from capitals indicating positive powers, was k for kilo. The SI came into existence (1960) around the same time as I learned this, so my teacher (my mother) was probably not influenced by the authorities in Paris. In fact, I don't think I ever encountered da for deka before reading this article! Deka is probably the least used prefix.--King Hildebrand 16:40, 2 August 2006 (UTC)

[edit] deka

What is the correct form for deka? I think "k" is better than c, since the word derives from greek. Besides da, dk is also a common abreviation of deka (at least in the case of dekagram - dkg).Timur lenk 00:50, 24 September 2006 (UTC)

If you look at the the article's first external link, The International Bureau of Weights and Measures (BIPM): SI prefixes, you will see deca and da recommended. If you look at the third external link, US NIST "Definitions of the SI units: The twenty SI prefixes" you will see deka recommended, but the symbol recommendation is the same, da. So either is acceptable, but deka is preferred in the USA and deca is preferred elsewhere.
I live in the USA, and I don't recall ever seeing the deka prefix used, no matter how it is spelled. --Gerry Ashton 04:45, 24 September 2006 (UTC)
Thanks for the info. I live in Hungary and deka is commonly used in dekagram to measure mass in retail (typically sausage, cheese or such in a mall or grocery). The most widespread abbreviation is dkg, but very rarely dag can be seen as well. The form dkg is thaught in schools, too. Despite the practice in some other countries, grams are never used to measure mass (weight) in shops/groceries (you never ask for 300 g but for 30 dkg of cheese).
In an interwar Hungarian schoolbook (from the 1930s) I have seen deka as prefix of meter (forming dekameter), but it is totally unknown nowadays. Since the metric system was implemented by law in the 1870s, it can be an archaism - like myriameter (10 000 meter), which I have seen only in the above law.Timur lenk 10:10, 25 September 2006 (UTC)

[edit] Kilo, why k and not K?

Just a question if anyone knows. Why does kilo use (small) k and not (big) K as the other larger than 0 units? It's the same with deca (da) and hecto (h) but they are a bit outside since they don't follow the tree step thingie, so I can accept them. But I feel kilo should be K. So, why isn't it?

I ask this question because MSWord wants it to be K but safe sources say k. —The preceding unsigned comment was added by Thavox (talk • contribs) 11:49, 6 March 2007 (UTC).

[edit] Excessive use of symbols

User: AnyFile recently revised the lead paragraph to avoid using spelled-out units and prefixes when preceded by a number. AnyFile stated that such usage was "not allowed by SI rules." I have seen style guides that encourage the use of symbols in scientific writing, but I am not aware of the prohibition mentioned by AnyFile in any publication that has the force of law. Furthermore, I believe spelling out the units is appropriate in a paragraph that is introducing readers to the concept of SI prefixes, advice in any style guide notwithstanding. --Gerry Ashton 14:03, 4 April 2007 (UTC)

Retrieved from "http://en.wikipedia.org../../../s/i/_/Talk%7ESI_prefix_608c.html"