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    (Wasn't to sure about the topic section to put this in)

    Of course, I understand why its more dense than ice.
    What I dont understand is how it can be!

    Could you please answer this specific question:

    Ice has a density of 0.917 g/cm2 at 0C, whereas water has a density of 0.9998 g/cm2.

    So if I was to take a bucket, containing 100cm2 of water, seal it and then freeze it.
    When it is ice, would it weigh the same, less, or more?
    Under the underlined sentences logic, it should weigh less.
    If that's true, what has happened to the excess weight?!

    Please bare with me, I'm not a chemist by any means.
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    ice has an open structure with air gaps in it or something
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    (Original post by lonelykatana)
    (Wasn't to sure about the topic section to put this in)

    Of course, I understand why its more dense than ice.
    What I dont understand is how it can be!

    Could you please answer this specific question:

    Ice has a density of 0.917 g/cm2 at 0C, whereas water has a density of 0.9998 g/cm2.

    So if I was to take a bucket, containing 100cm2 of water, seal it and then freeze it.
    When it is ice, would it weigh the same, less, or more?
    Under the underlined sentences logic, it should weigh less.
    If that's true, what has happened to the excess weight?!

    Please bare with me, I'm not a chemist by any means.
    When frozen, water actually expands, and this is a common erosion process in both man-made structures and the natural environment, referred to as a 'freeze-thaw' process. In your example, the mass of the bucket wouldn't change, but if there was no air in there (into which the water could expand, compressing the air) then you could well see the bucket rupturing as freezing occurs.

    It's not immediately straightforward to explain the full details of why water has the higher density, but basketofsnakes is correct that it's related to the crystal structure of ice and the bonding between atoms (specifically, hydrogen-bonding in ice).
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    Physics section I would imagine.

    The water/ice doesnt weigh more/less, that stays constant. Notice density is grams/cm^3. If weight (edit: I mean mass) is constant (as you have correctly assumed is the intuitive answer), the the volume must decrease/increase to compensate.
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    Simply: In ice hydrogen bonds keep the molecules apart. This forms a lattice where the molecules are held further away by the hydrogen bonds then they are when they're in water
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    it means if you have the same volume of ice and water the ice would weight less. but if you have the same weight of ice and water the ice has a large volume. so if you take an amount of water and freeze it no water disappears it doesn't weigh less as it changed to ice it expands and takes up more volume because the particles are packed less closely together in ice
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    That's why peoples' pipes are bursting.
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    Your cracker problems ain't ****
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    (Original post by Ricky116)
    Physics section I would imagine.

    The water/ice doesnt weigh more/less, that stays constant. Notice density is grams/cm^3. If weight (edit: I mean mass) is constant (as you have correctly assumed is the intuitive answer), the the volume must decrease/increase to compensate.
    This explained it perfectly. Thanks very much.

    But now I feel like a complete moron for not realising that :p:D
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    Hydrogen bonding...
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    It is due to hydrogen bonding. In ice, the water molecules arrange themselves in such a way as to maximise the amount of hydrogen bonding between the molecules. This results in a very open hexagonal structure with large spaces within the crystal. This accounts for its low density.

    When the ice melts, the structure collapses into the open spaces and the resulting liquid, despite being less ordered, occupies less space and is thus more dense.

    Thus ice floats on water.
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    yeh, as density = mass over volume, as mass would stay the same the volume adjusts the density
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    Icebergs 90% underwater, ocean made of salt water...

    Ocean density = 1.027gcm^-2

    Ice density = 0.9167gcm^-2

    => Ice density < 90% of ocean density

    Melt icecaps to combat rising sea levels. Just saved the mother****ing planet.
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    (Original post by LaughingBro)
    That's why peoples' pipes are bursting.
    It's also why after some icy weather, the roads end up full of potholes.
    (Original post by Jambre)
    Icebergs 90% underwater, ocean made of salt water...

    Ocean density = 1.027gcm^-2

    Ice density = 0.9167gcm^-2

    =&gt; Ice density &lt; 90% of ocean density

    Melt icecaps to combat rising sea levels. Just saved the mother****ing planet.
    You're joking, right?
 
 
 
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