# The Concept of Precipitable Water (PW)

#### CbIncus

##### Member
As many chemtrail people try to convince others that barium salts in chemtrails absorb atmospheric water, this post offers a way to debunk this claim.

The definition of precipitable water (PW) is the following (from Wikipedia):

Precipitable water is the depth of water in a column of the atmosphere if all the water in that column were precipitated as rain. As a depth, the precipitable water is measured in millimeters or inches.
Content from External Source
The derivation of formulas can be found here: http://www.engr.colostate.edu/~ramirez/ce_old/classes/cive322-Ramirez/CE322_Web/PrecipitableWaterExample.html.

To make it more intuitive, one should remember that 1 mm layer of water is equal to 1 kg/m^2 per column. So typical value 30 mm of PW means 30 kg/m^2 of water. And it's just one square meter. Now imagine PW over a city, over a country. It's a pretty impressive number, isn't it?

And they still say that small quantities of salts can absorb moisture.