Talk:Conversion of units/Archive 2007

information enthropy SI unit for information enthropy = J/K???

This one looks really weird to me. It's quite possible that it's a correct unit, but deriving information entropy from energy and temperature looks really weird to me (as either concept not really is a core concept in information theory, however information entropy is). On the other hand, someone found really neat looking conversion factors, and there are relations between information theory and thermodynamics, what is where the unit really looks to belong. So, what I request is a reference for more information on this topic, to learn more about it. Also, information entropy should be extended with this info. TERdON 14:03, 3 January 2007 (UTC)

Is the 7.839695(13) × 10−23 J/K for byte in the information entropy correct, i think the -23 in the exponent should be -20, 7.839695(13) × 10−20 J/K.

I'd love to learn how that makes sense, too.. I don't think I'd ever use the information but .. I don't know, maybe I could whip it out at some kind of nerdy party. Looks just as weird, interesting and alien to me as it does to you, for the same reasons... After unsuccessfully parsing it (yielding units of energy and temperature) I fell back on seeing it as "Just Kidding"... 125.236.211.165 (talk) 13:31, 26 August 2008 (UTC)

The definition of Shannon entropy and Gibbs entropy are identical except for the k_B factor and the bases of logarithms, that is, the latter equals the former times k_B ln 2. So, in some sense, 1 bit = k_B ln 2 = 9.569939(17)×10⁻²⁴ J/K; Whether they actually measure the same thing is another matter... --A r m y 1 9 8 7 ! !  09:44, 2 September 2008 (UTC)

US Gallons / US Fluid Ounce

In other articles the US Fluid Ounce is defined as 1/128 of one US Gallon. However given the conversion factors in this article (1 US Gallon) / (1 US Fluid Ounce) = 133.2278695406382. Why is this? OlJanx 05:17, 3 February 2007 (UTC)

Please provide some search text so we can find which line in the table you are writing about. --Gerry Ashton 05:42, 3 February 2007 (UTC)

The following are lines from the Volume table:

fluid ounce (U.S.) fl oz (US) ≡ 1/128 gal (US) = 29.573 529 562 5 mL

gallon (U.S. fluid; Wine) gal (US) ≡ 231 cu in = 3.785 411 784 L

The conversion between the two units can be done like this:

(3.785411784 L)/(.0295735295625 L) = 133.2278695406382

--67.165.215.241 21:47, 3 February 2007 (UTC)

When I do the calculation (3.785411784 L)/(.0295735295625 L) with a TI-36X calculator, I get the answer 128.0000024. Perhaps your calculator is not working properly due to the many digits; try entering shorter approximations into your calculator, such as 3.7854/0.02957 and see if you get an answer close to 128. --Gerry Ashton 22:00, 3 February 2007 (UTC)

I tested the above calculation on a TI-84 and got the answer 128. The error was apparently a typo on my part. I apologize for not properly testing the issue before bringing it up in this discussion. --OlJanx 07:38, 4 February 2007 (UTC)

Should this article be a list?

This article seems that it should be an explanation of what conversion of units is and how to do it, not a list of conversion of units. Maybe we should start another article that could be something like common unit conversions. Also, Software tools is at the end of the page, after the table, that should at least come before it, so that its actual will be read. Finally, mass has an empty column "relation to avoirdupois," which as I understand it is the English weight system. Either we should have Imperial units in there, or not, but we shouldn't have an empty column.Markid 04:36, 1 March 2007 (UTC)

List of unit converters?

Well, just a suggestion. But would it not be an idea to list some free unit converters in external links?

e.g. http://library.thinkquest.org/11771/english/hi/chemistry/convert.shtml http://www.micro-sys.dk/services/unit-convert/ http://www.convert-me.com etc. —The preceding unsigned comment was added by 83.88.199.154 (talk) 11:59, 12 March 2007 (UTC).

... and here's one that I've removed from Metric system ...

• Online Unit Converter Metric to Imperial

Also it has been suggested that http://www.theconvertersite.com be added to Metric system. Jimp 00:19, 17 May 2007 (UTC)

Given that wikipedia is a powerful source of incoming traffic for a website, and that unit conversion is a frequent search, and that many of these free sites use advertising, which can potentially bring in a lot of money, I think the criteria needs to be very strict. Any site that has openly commecial content is unlinkable as per standard wp policy. But sites that contain advertising on the unit conversion page should also be excluded from being linked here. Rhialto 06:14, 17 May 2007 (UTC)

Well, I couldn't agree more and I have just checked the five sites mentioned. The first of these is "Currently Unavailable" and the remaining four do contain advertising or links to advertising pages. Why don't we have our own converter? There's a job for the Wikimedia developers. Jimp 05:55, 23 May 2007 (UTC)

A basic principle is that Wikipedia is NOT a link directory. Any external links must actually add information over and above what's in the article—a site that simply lets you fill out a form to convert units does not qualify. I've removed some of them , most of them should probably go. —johndburger 03:44, 11 December 2007 (UTC)

Mach speed

Should this be added to the list? I know that it varies from temperature and air volume. Thanks, user:marasama 3/25/07.

Technical atmosphere

A definition was just added for atmosphere (technical). Can a source be provided for this definition? --Gerry Ashton 17:45, 10 April 2007 (UTC)

Meter Vs. Metre

I know this is picky, and I know the difference, but shouldn't some have the alternate spelling next to it? EX: Metre (Meter- US spelling) or something like that? just asking. SRodgers--65.24.61.74 03:41, 19 April 2007 (UTC)

I would think the place to discuss spelling would either be in the Metre article, or in a dictionary. This article is about converting units, not the finer points of each unit listed. Are you concerned that someone will think metre and meter are two different units? --Gerry Ashton 04:46, 19 April 2007 (UTC)

FYI, the guideline is to leave the spelling either British or American, whoever got there first. —johndburger 02:59, 18 May 2007 (UTC)

atomic units

The table gives au as the abbreviation for atomic units of both mass and length. Rowlett gives u or amu for the mass unit but I can't find the length unit there at all. Rowlett also quotes au as an alternative abbreviation to AU (or ua) for the astronomical unit (of length). In short, I am confused. Thunderbird2

All atomic units can be referred to as au. In the rest of the tables au is used, except for energy and length. I've stuck au in here. One could argue that m_e is just as valid as a₀ and E_h as all are physical quantities. Electron mass is more measurable than Bohr radius, though! AMU is most often used to mean the atomic mass unit. 210.9.137.252 (talk) 16:08, 10 July 2008 (UTC)

Wikipedia is not a howto manual

This article needs to be about about how units are converted not how they should be converted. The techniques section and intro should be replaced by discussion of actual practices, with appropriate verification. For instance, when (and when not) are sig figs used in practice? Do people use the best conversion factors available? Superm401 - Talk 12:55, 13 November 2007 (UTC)