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Why does the surafce of a liquid act as a stretched membrane?

  1. Mar 16, 2013 #1
    Dont give me the answer that its because of surface tension. I want it in detail.
     
  2. jcsd
  3. Mar 16, 2013 #2

    davenn

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    so google surface tension then and find out what its all about :)
     
  4. Mar 17, 2013 #3
    I thought that one of the aims of PF is that we do not simply refer someone to Google.
    Why come here to be told to go to Google?
    Perhaps you came here from Google !!!
    Very sloppy, no use at all.
     
  5. Mar 17, 2013 #4
    @Emilyjoint your both right and wrong.
    People who come here and ask questions like what is water or what is wind should be directed to google.As some of them are ignorant and some just really don't know how and where to look for answers.

    Now the ones who come here and ask for a more in depth advice after they atleast read the basics of the subject and came to some understanding of it now that is a different case we certainly shouldn't send them "around the corner".
    Which case is this I don't know for sure not really my field.

    As much as I do know that it has to do with the weight of the object / liquid viscosity and the weight to surface ratio of the object that floats on the surface. Now from basic physics we know that everything that is either "sharp" or dull or round or flat or whatever and has weight exerts a force on the surface on which it stands (not only liquid) like a nail being pushed on wood leaves a point mark, or a stick on soil and ground or any other such material.
    Now liquids are usually less dense than solid matter that's why they are easier to puncture or go through them.
    Although ice is less dense than water and that is why you see ice floating on top of water rather than below or sinking.That's because if something has a large surface are like a block of ice but is less dense than the liquid on which it sits it means that per given area it is also has less weight so it can float.But remember that it has to do with the weight/surface ratio that determines what floats and what sinks. You could put a stainless steel plate in the size and weight of a similar floating ice piece on the surface of water and the steel will drown because it's alot denser than the ice and hence heavier.
    That's as much s I can tell you.That's pretty much detail , do you want more? Like the quantum level maybe ? :D
     
    Last edited: Mar 17, 2013
  6. Mar 17, 2013 #5

    sophiecentaur

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    This reads like a review in 'trip adviser'.
    Someone coming from google (after giving it a good try) would be expected to have a specific question, involving something that google had already given them. We all know about Wikipedia, don't we? If PF gets a wide open question then, for a start, there is no way of knowing what level of answer is required. PF is not a free tutoring service; it's exists because people like to discuss things at all sorts of levels. One of the 'rewards' that they expect is that people demonstrate that they have made some attempt at finding stuff out rather than just expecting to be spoon fed.
     
  7. Mar 17, 2013 #6

    davenn

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    Emilyjoint

    the problem is, that people seem to have forgotten how to do basic research, or are just too plain lazy to do it and expect all the answers to be handed to them on a silver platter.!!

    I for one will normally not bow to that sort of situation

    You will find the majority of skilled people on here would prefer for the person asking the questions to have least done some of the basic footwork first... THEN and only then when they may have some lack of understanding of what they have found ask some really valid questions about their non/misunderstandings

    In the end the poster is going to have a much better understanding of the subject as they have, at least, done some background reading :)

    Dave
     
  8. Mar 24, 2013 #7
    i could not get my answer here.
    I browsed elsewhere and found out that it tries to minimize the area to attain the least possible potential energy. Thus its surface will try to have minimum molecules thus making its exposed area stretched.
     
  9. Mar 24, 2013 #8

    sophiecentaur

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    That's a very fair description (energy is always a good basis for an explanation) but I do have one reservation. It is better to use wording that is not anthropomorphic when describing natural phenomena. Nothing that is non-biological, actually "tries' to do anything. Such terms were common in ancient Science - as in "nature abhors a vacuum" - and we have progressed past that and we don't attribute a 'will' to inanimate things these days. There is always an alternative to "tries to" and the process of digging it out can be very useful for increasing ones understanding aamof.

    How things are expressed in casual conversation can be much more loose, of course, because the inter-personal interactions can take care of misunderstandings.

    If you think I'm being picky then consider a man, accidentally falling over a cliff. Does he fall to the bottom because he is "trying to"? :biggrin:
     
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