Talk:Density

The article says that densities should be specified in kg/m3 - yet the table of sample densities are in g/cm3. This is not a good thing! The numbers need to be 1000 times larger and the units at the top of the table changed.

Would someone please add an entry for ice? Thanks! Aspie 23:38, 4 October 2005 (UTC)

SteveBaker says: The generally accepted figure is 917 kg/m3 - but density varies with temperature. I presume the table in the article is for densities at room temperature - and you can't say what the density of ice is at room temperature!

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andre **** you. **** your mother, father, sister, brother and all your family. Water isn't really defined to have density 1 is it? That's a schoolboy definition. --drj

Mayhaps, I certainly was a schoolboy once :-) The fact that one litre of water weighs exactly one kilogram os no accident however. The SI units were chosen carefully, although i know not if the metre or the kilogram was defined first (my money is on the metre), the relation between them is indeed found through the density of water (at 4 degrees celsius if memory serves correctly). --Anders Törlind.

Oh, by the way, is the kilogram still defined as the lump of platinum they hold in Paris, or is it defined as a certain number of atoms of something? --Anders Törlind

I wondered about this recently. My research confirms what kilogram says. There is a standard mass made from platinum/rhodium. I guess it is too difficult to define it as the number of atoms of something. --drj

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I believe that the metere was originally defined to be 1x10^-6 of the distance from the equator to the north pole via a line that went through Paris, this was mesured incorrectly at the time, so the distance is somewhat different. The other units as far as I know are based on that. The kilogram was originally based on a cubic decimeter of water, but that is much too variable to be used as a reference.-- mike dill

Actually, one ten-millionth, which is 10^-7. (I fixed your tags.) Vicki Rosenzweig

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Do you have the reference for the platinum density of 21.09? According to http://hypertextbook.com/facts/2004/OliviaTai.shtml, the density is 21.45 and they list 5 references. When I Google platinum density, the first entry webelements.com (another wiki) agrees with 21.09, but going on down the list several pages, everyone else says from 21.4 to 21.5. If you change to 21.45 then change the Wikipedia platinum article also. Art LaPella 05:04, Aug 22, 2004 (UTC)

I have checked the CRC Handbook of Chemistry and Physics (60th edition, page B-106) and it gives 21.45 at 20 degC: so have changed here and on the platinum page. --GPoss 06:36, Aug 22, 2004 (UTC)

For the record, the 21.09 value apparently originates from Lange's Handbook of Chemistry, McGraw-Hill (also cited by WebElements, and standing rather lonely among the other references). Femto 12:00, 14 July 2005 (UTC)

Osmium vs Iridium

It seems the articles for Osmium and Iridium give different values for the density of Osmium compared to the value in the density table, affecting the order of the elements in the table. Apparently Osmium should be listed at 22661 kg/m³ rather than 22610 kg/m³. --Vinsci 14:48, 4 Apr 2005 (UTC)

--- It looks like those two articles now both explain that the difference in density between Osmium and Iridium is so small that it takes theoretical calculations of density to tell the difference between them. This article is far too definitive about Iridium being the densest. The language should be loosened somewhat.