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Strange behavior of the density of the water around the freezing point

  1. Apr 4, 2010 #1
    please is there a topic that discuss with illustration factor that causes Strange behavior of the density of the water around the freezing point
     
  2. jcsd
  3. Apr 4, 2010 #2

    DaveC426913

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    Gold Member

    Can you be more specific?
    Do you mean why it begins to expand?

    That's fairly simple; water begins to expand because its poles are trying to line up so it can form a crystaline matrix.

    Get ten people to crowd together in the centre of a room with their arms outstretched. They could probably crowd together pretty closely - outstretched arms overlapping and intertwined - if you herded them together.

    Now, with their arms still outstretched, tell them to move around so they can hold hands with each other. They won't be able to grab each others' hands until they step back a pace or two. They'll take up more of the room.
     
  4. Apr 4, 2010 #3
    I presume you mean the fact that the maximum density is around +4 degrees centigrade?

    This is due to the highly polar nature of the water molecule because of its shape.

    Please note this is only applies to fresh water ie pure water. Water with dissolved material eg seawater does not exhibit this phenomenon.
     
  5. Apr 4, 2010 #4
    i meant with strange behavior that water contradicts the role of decreasing density due to increasing temperatur at a range from 0 c degree to 4 c degree
     
  6. Apr 4, 2010 #5
    yes sir thats exactly what i meant but i want to know with more diagramatic illustration the effect of molecule's shape on this behaviour i thought that such basic phenomena had a lot of discussion in previous threads
     
  7. Apr 4, 2010 #6
    Is your question, why is water less dense at 2C than at 4C even though it isn't ice?

    Heck if I know. I'm not a chemist. But as an aspiring odds-maker, my money says that an increase in the time that hydrogen in one molecule temporarily bonds to oxygen in another dominates over the thermal agitation that would separate them.

    Was that the question? If so, I wonder what the density curve of supercooled water looks like.
     
    Last edited: Apr 4, 2010
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