I don't really understand surface tension. I understand that the molecules at the liquid surface will be attracted downwards due to the resultant force caused by the attraction between molecules. However, this statement in my textbook baffled me. "Consequently molecules in the surface have potential energy." What does it really mean by that? Is potential energy between molecules due to the intermolecular attraction? There's another statement on wiki : "Another way to view it is that a molecule in contact with a neighbour is in a lower state of energy than if it weren't in contact with a neighbour" Why is that so? Why is that the molecules at the surface have higher state of energy and what does state of energy mean? Is it potential energy? Furthermore, why are there forces acting upwards on a needle due to surface tension? Can anyone explain it more clearly? I understand the water will have indentations on it due to the extra force caused my the weight of the needle but what effect does the molecules on surface has on the needle which resulted in the upward forces? One last question. Why is it that there are two forces acting upwards on the needle instead of a single one? Thank you in advance. Surface tension has been plaguing my mind for a long time and I could not comprehend it clearly.