What causes liquid to rise in a capillary tube?

[AudioFlux]

This question struck me when i was watching a liquid rise in a capillary tube. I'm curious to know from where the energy gets transferred to the liquid to rise above the surface. Well, one possible explanation that i can think of is air pressure. Though, it can be a possible reason only if the other end is closed (i don't remember if it was open or closed). So am i on the right track?

 

[tiny-tim]

Hi AudioFlux!

I'm curious to know from where the energy gets transferred to the liquid to rise above the surface. Well, one possible explanation that i can think of is air pressure.

No, it's surface tension, see …

http://en.wikipedia.org/wiki/Capillary_action#Height_of_a_meniscus
http://en.wikipedia.org/wiki/Wetting
http://en.wikipedia.org/wiki/Contact_angle

(if the contact angle is greater than 90°, the solid surface is hydrophobic, and the liquid will fall …

this is how those damp-proofing injections work, they line the capillaries in the bricks with a hydrophobic lining)