"Ray" wrote in message
...
OK, Peter. You're going to have to help me with this one:

You stated "Humid air is lighter than dry air". How can that be? Humid
air
is dry air containing water vapor, so how can (stating it mathematically)
X + Y X ?

In reality, the heavier, humid air will stay settled around the plants
until
diffusion or forced dispersion moves it away.

You're right: humidity trays may not help much, or at all, but they do
protect the furniture!

--

I know it's counter-intuitive but it's true - humid air is lighter than dry
air. Water vapor is lighter than air. In perfectly dry air you have 100%
air. In humid air you might have 90% air and 10% water vapor (I made those
figures up but they will serve to illusrtate). The water vapor replaces some
of the air, it does not add to it. So, lighter water vapor replaces heavier
air, the end result is lighter. I wish I could explain it better, but I
remember this fact distinctly from when I studied meteorology.


--
Peter Aitken

Remove the crap from my email address before using.