Talk:Centimetre or millimetre of water

Can someone verify the cm-H2O to PSI conversion?

I'm uncomfortable making claims on this, but when doing some rough calculations converting one to the other, the result was roughly a decimal magnitude off from the ballpark answer I was expecting.

Thank you 140.146.206.8 (talk) 02:00, 23 January 2015 (UTC)

The number looks about right to me. Meters (talk) 02:44, 23 January 2015 (UTC)

Okay, I will play.

Looking at Pressure head, we can find out that there is a 13.6 factor difference between mercury and water column measurements. If you have 1 torr, or 1 mm of mercury, this is like 13.6 mm of water. This is also like 1.36 cm of water. There is your conversion of interest. 1 cm of water is therefore about 0.735 Torr (the article says 0.73556). This represents (See Template:Pressure Units) 1.933678×10−2 x 0.735 = 0.0142 psi. The article says the same thing. I would confirm the article, as written, to at least some rudimentary level of accuracy and confidence level. I like to saw logs! (talk) 05:23, 25 January 2015 (UTC)

I did it differently, but got the same confirmation. Meters (talk) 06:36, 25 January 2015 (UTC)

Column width

1: What width is the column ? Because a 1cm width (inner diameter) column is much easier to raise than a 20cm column!

2: It's a cylindrical column, right ? Or a square column? It's usually a cylindrical column, as in a tube. But a square (cross-section) column fits better with most calculations, although it's a lot rarer to find, in laboratory apparatus! DaveDodgy (talk) 16:15, 29 April 2016 (UTC)

This is the pressure exerted by a column of water. The shape and size of a physical column is irrelevant since we are discussing a pressure (force per unit area) rather than a force.