While deriving the equation of height to which the fluid rises, we say that the surface tension pulls the water till the weight of water balances it, my doubt is that how can any force pull on something that is liquid?
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$\begingroup$ water.usgs.gov/edu/capillaryaction.html $\endgroup$– user81619Oct 10, 2015 at 17:53
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$\begingroup$ Why can't "any force pull water"? $\endgroup$– SchrodingersCatOct 10, 2015 at 17:57
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$\begingroup$ Related: physics.stackexchange.com/q/2254/2451 and links therein. $\endgroup$– Qmechanic ♦Oct 10, 2015 at 18:04
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$\begingroup$ A force can't pull water because water can't withstand shearing stress, it will deform. $\endgroup$– ashwini abhishekOct 12, 2015 at 21:49
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1 Answer
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When you are sucking a liquid with a straw, you are pulling a liquid by creating a low pressure in your mouth. This is similar with capillary rise: the surface tension has for effect to reduce the pressure of the water beneath the air-water interface. As a result, water rises until the pressure is balanced. The "pull" is transmitted down by the cohesion force between water molecules.