Talk:SI derived unit
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Hmmm. Are I'm infringing ones copyright by taking commonly used definitions??? Tobias Hoevekamp
what is a liter?
- Hmmm, seems to be a Cubic Decimeter. I think it would fit here. http://en.wikipedia.org/wiki/Liter
- "The litre (or liter in US) is a metric unit of volume. The litre is not an SI unit, but (along with units such as hours and days) is listed as one of the "units outside the SI that are accepted for use with the SI." The SI unit of volume is the cubic metre (m³)." So it seems like it's Metric, although not SI derived...
Woulnd't it be better to try to make this chart more free form, using indentation to get pre formatting, as with periodic table, so that it is easier to edit?
Although they are derived units, there are standard base units for derived quantities such as area (the are, as in "hectare") and the liter, these should be included, just as have been units like webers etc.
I'd do it, but frankly, I'm a bit put off by the table markup. Maybe I'll make an alternative table to demonstrate how I think it should be done.
And no, I don't think it's a violation of the copyright to transcribe facts, so long as you don't make an exact copy of the layout from the original. I saw someone address this issue recently in another context, I'll see if I can dig up the discussion and then post a link to it here.
-- dja
Ah, here we go, perhaps Lee Daniel Crocker's comments in United States/President might reassure you. If not, perhaps this is a question for talk:Copyright?
-- dja
Yes, I don't see anything copyrightable here. Even if you took whole sentences out of the ISO specs, they're not copyrighted either--deliberately. That's the whole purpose of the ISO. --LDC
(Internation Standards (published by ISO) are copyright, the copyright is owned by ISO, they reserve all rights. There is no right to copy anything from an International Standard. Obviously this is often a problem if you want to implement, use, or descrribe one. Providing copyright free specifications is not the purpose of ISO. Alas. --drj).
Are you sure that ISO waives their rights? ISO charges big bucks for most standards as a way to finance themselves. If these were really public domain, we would have seen a lot of them printed cheaply, or floating around the net, no? --Robbe
Yes, some (OK, most) ISO specs are copyrighted--especially industrial standards. But they do grant explicit rights to the metric weights and measures stuff. I'll see if I can dig up a citation somewhere. --LDC
Something like this: SI derived units freeform table
I started by reading the HTML-formatted table with the character-based web browser "links" in a sufficiently wide terminal window, saving the formatted output to a file. I then passed it through the following perl one-liner to preserve the free formatted links, and to restore the superscripting:
perl -ne 's/|/ /g; s/[(S+s*S*s*S*)]?/$1/g; s/(S+)?/$1/g; s/(w)(-*d+)/$1$2/g; print' si_derived_units.txt > si_derived_units5.txt
Finally, I did some manual cleaning up in a text editor before copying and posting it.
FWIW, YMMV, and all that.
-- dja
Neither SI derived units freeform table nor SI derived unit look good to me. What I don't like is, that we are restricted to very basic mathematical formulations... -- th
Do you have an example of what would be more appropriate? Seems to me that one is going to run into such limitations with any tabular format. The freeform table is not intended so much for its prettiness (although I don't think it is downright *ugly* even so), but rather to make the layout more accessible and editable by people who are more interested in the content than in the minutiae of HTML markup. Such concern is fairly central to Wikis, in general.
-- dja
Problems with the freeform table: (a) It is difficult to get the alignment right, because the link brackets (4 chars) can turn into zero, one (the question mark), or three chars (? plus brackets). If somebody creates one of the dangling links on your page, the alignment changes and must be fixed. (b) Browsers may word-wrap PRE content, which makes the table almost unreadable. Mozilla does this. (c) SUP is not allowed inside PRE, and therefore most of the units are broken (m^2, m^-1, etc.). --Robbe
(a) Granted, though perfect alignment isn't always necessary (b) OK (c) I see that this is so from
http://www.w3.org/TR/html4/sgml/dtd.html#pre.exclusion
Good thing I didn't change the main page too early. :-)
--dja
As_I_Understand_It, degree Celsius is NOT an SI unit, the Kelvin is. Anyone know how to confirm / refute this? SGBailey 10:34 Dec 12, 2002 (UTC)
I have started changing some of the math formulas to use <math> constructs. I think this looks much better, and is not much more difficult to edit (see Wikipedia:TeX markup). If nobody objects, I will finish this off sometime soon. I agree that the freeform table looks pretty bad, and the html table isn't much better. I don't think the html table is too difficult to edit, but maybe I will format it in a way that makes it easier for people to understand how to edit. Or maybe I'll make my own attempt at a freeform table. We'll see... --HN 21 May 2003
Why not use Wikipedia table markup instead? (Random832 01:05, 14 Jun 2004 (UTC))
I dont see the dyne (symbol: dyn) mentioned here or on the force page. It appears to have a defined relationship with the newton. Is it a bastard unit of measure?
- Quinobi 21:16, 2 Oct 2004 (UTC)
- Follow http://www1.bipm.org/en/si/derived_units/2-2-2.html and you will find that the dyne is 'not accepted' for use with SI (by omission). Contrast this with the deg Celsius which also has a defined relationship with an SI unit - kelvin, but this one is 'accepted for use' with SI. Dyne appears in the CGS system of units, which is very much less widely used than SI. Ian Cairns 21:36, 2 Oct 2004 (UTC)
Maths notation
Does anyone else find the page extremely s..l..o..w.. to load - principally because of the huge amount of maths involved in simple text fields? I would like to replace the maths by text, with a suitable appearance / emphasis. Does anyone have any objections, please? Ian Cairns 00:16, 8 Nov 2004 (UTC)
Templates
There are templates available e.g. [[Template:SI_derived_units]] and [[Template:SI_accepted_units]] which could be used to start this article. Would they be useful in this article? Ian Cairns 00:31, 8 Nov 2004 (UTC)