• Question: Why don't oceans freeze?

    Asked by to Kieren, Rowena, Roy on 20 Mar 2014. This question was also asked by .
    • Photo: Kieren Bradley

      Kieren Bradley answered on 20 Mar 2014:


      I think this question has actually been answered on here before, but quickly, they do freeze, hence why you see the north pole covered in ice, but they don’t freeze at the same temperature as fresh water because salt lowers the freezing temperature so there isn’t as much ice as if they were made of fresh water.

    • Photo: Roy Adkin

      Roy Adkin answered on 20 Mar 2014:


      What is more interesting is why the sea and ponds don’t freeze solid all the way down to the bottom! Water is most dense at 2 degrees centigrade so at that temperature the water sinks and the colder water (less than 2 degrees) rises and freezes…the water with the salts and other chemicals dissolved in it is also denser so that sinks and due to the impurities the water’s melting pint also decreases which means the water is not going to reach a temperature that will allow it to freeze. Oceanographic hydrology is fascinating…I did a module on it for my degree!

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