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Understanding Surface Tension

  1. Jan 23, 2014 #1
    I am studying surface tension and I am summing up what I have learnt through books till now:

    → On a molecular level, due to unbalanced forces on the uppermost level, the liquid molecules tend to
    go down the liquid.

    → As the molecules go down, the uppermost layer shrinks in size and tries to go down. As it does
    so, such a point is reached where it can no longer suppress itself against the pressure offered
    by the liquid beneath it.

    → As a result, the layer becomes perfectly horizontal and behaves like a stretched membrane. The
    force per unit length experienced by the molecules on the surface film is called surface tension.

    → The particles on the outermost layer has some potential energy (ie Surface energy) which
    originates from the work done in moving upwards against the intermolecular forces.

    Now, my question is: How is potential energy related to the surface area?And, how is surface energy a cause for surface tension? Can anyone explain these to me?

    Thanks for your help!

    P.S- I read the wikipedia article about surface tension and went through a few other sources but I am not really convinced of how potential energy stored in the molecules lead to surface tension?
    Last edited: Jan 23, 2014
  2. jcsd
  3. Jan 23, 2014 #2

    Simon Bridge

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    You can work out the relations you want by calculating the potential energy, and thus the "surface energy", yourself. I don't think we can say that the surface energy "causes" surface tension ... it is more another way of describing it. The tension and the energies are perhaps better thought of as an emergent effect "caused by" the interactions between molecules.

    What education level are you doing your studying at?
  4. Jan 28, 2014 #3
    I am a high school student.
  5. Jan 28, 2014 #4

    Simon Bridge

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