taken from TAG landing on ICmag.
http://www.icmag.com/ic/showthread.php?t=15115
The basic principles of aeroponic delivery are the rapid exchange of gases between the membranes of the root subculture and the plant roots. Application of a micro-fine nutrient film that is readily absorbed and evaporated before the next aerosol cycle is the goal.
The need for 50µ-target size for micro droplets is based on the findings by researchers that the average tube opening on the root hairs is approximate 20-50µ or within a range from 5-100µ.
The specific reason for this importance is as follows:
Aero isn't about DO. There really isn't that much in True aero, as I've mentioned. It has to do with uniformity of droplet size.
The mist that is created by these nozzles is micro fine and all the drops are pretty much the same size and an ideal size for optimum uptake.
You have a hundred different size balls that you are trying to get through a screen with holes that only fit things the size of a ping pong ball or smaller. Your standard mister is going to have like a 50/50 mix of sizes and the bigger ones have to hang out until something comes along to break it into several smaller balls kind of like the game 'asteroids' if you remember it.
True aero is a spray of balls that are all the size of ping pong balls or smaller, so everything goes right through the screen without having to wait to be broken up into smaller pieces.
That is what is happening on a microscopic level at your root level. The need for O2 is that it breaks down those H20 molecules and helps tear apart CO2 the O's are all what they call 'Free Radical' Meaning they bond with anything immediately. It is called Oxidation. That is why your blood is red, oxidized iron in your blood. It is how hemoglobin is created. All cells respire gases...it is smaller than water vapor or even the molecules themselves. O2 is a gas, CO2 is a gas, Nitrogen is a gas, Hydrogen is a gas these are all gases that when combined together to make a 'big ball' make water H20 or CO2 or any of the elements you are feeding your plant.