Hello all. This is my first post and I wasn't exactly sure where to put it, so I apologize if it could be in a better place. Ok... here is my issue. I am currently enrolled in a Surfaces/Interfaces course. Capillary action eludes me. I do not understand WHY capillary action occurs in relation to interface pressure differences. I have attached the slide in question. My biggest confusion is the line "because of the pressure difference...". What about the pressure difference causes the liquid to rise up the tube? It seems counter intuitive. If the surface is curved as shown, this implies that the pressure of the air is greater than the pressure of the liquid (ΔP wrt to liquid is negative). It seems like the greater pressure would push DOWN on the water and cause it to go down the tube.... Any explanation of this would be VERY helpful! Cheers!