50/50 methanol-water Vs. water

[JohnA]

Originally Posted by GotH2O

A 10wt% methanol in water reduces the surface tension of water 25%! The effect tapers off as the methanol content increases

Where did you get that figure from? :?:
Empirically it feels right, but I'd be interested to see further 'hard' data

The surface tension is not an esoteric entity.
It's obvious even as you pour the mixtures into containers. Very low surface tension results in droplets popping out very easily, so you have to be careful to avoid rinsing your eyes with methanol.
Water behaves, well, like water, so adding 10% methanol immediately has it behaving half-way like methanol (which has low surface tension and is hard to pour without having splashes all around)

[Rootzz06]

forgive my ignorance but why is surface tension important?

[GotH2O]

surface tension measures the cohesive force between 2 similar molecules, in this case water. Its this property that allows the little water skaters to move around the surface of ponds. Put soap(surfactant) into the pond and the little insects will drown.
Methanol acts as a surfactant, lowering the cohesive forces between the water molecules, which in theory, allows finer droplets of water to be sprayed from the nozzle. Finer droplets = lower mass = easier to be carried by the air flow = better distribution to each of the cylinders.