Quote:
Originally Posted by HaveBlue
Solid ice sits on? -yes sea water. It is heavier than fresh water and sea water doesn't freeze.
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Actually thats incorrect. The polar ice is not frozen fresh water with liquid sea water below.
Sea water WILL freeze if it is cold enough at the surface, it won't freeze at 0 degrees like freshwater, but will freeze at many degrees below zero - which it is at the poles.
The reason the ice cap has liquid water underneath is because once you go further below the surface the water is warmer and not cold enough to freeze - remember the severely sub zero temperatures are air temperatures at the surface and the water itself provides an insulation against those temperatures when you start going down. plus you have to factor in warm ocean currents. But of course the surface of the sea, in contact with frigid air, will freeze.
Think of it this way, you get a very cold snap and the local lake freezes over, does it ever freeze all the way to the bottom? No. Even freshwater will not freeze absolutely solid.