Expert: Profile Closed - 1/5/2010

Question
I have a question pertaining to capillary action. The process relies greatly on the polarity of water and glass (the experiment will be done with glass unless you have another suggestion), so i figured that by passing electricity through water, i could speed up the process of capillary action as the delocalized electrons would add to the polarity of the molecules, speeding up the process. Is this at all possible? If so would a battery submerged in water suffice? Or would the electricity simply lead to electrolysis having no effect on my experiment therefore rendering it useless? A speedy answer would be best. Thanks mate.

Answer
Hi there, and thanks for your question

The problem with your idea is that capillary action does not depend on a flow of electrons; it's a balance between gravity (which tends to pull a liquid down a tube) and the surface tension of a liquid. Surface tension is a product of the forces between molecules of the liquid (intermolecular forces).

In other words, the polarity of water is important, but only as far as it pulls molecules of water together in a physical process. Passing electricity in to the solution would not affect the inTERmolecular bonds - which are the ones involved in surface tension and capillary action. Instead, it would, as you guessed, break the chemical bonds inside each molecule (inTRAmolecular bonds), and split water in to hydrogen and oxygen.

Hope that this helps and is clear; the reason your idea wouldn't work is that capillary action depends on forces between water molecules, whereas the effect of electric current is to break up individual water molecules. Capillary action is a physical change, but passing electricity in to the water would cause a chemical change instead.

Hope that helps, let me know if you have any follow-up questions.

Happy new year, George.