|MadSci Network: Chemistry|
Kate, You are both wrong. Ice floats because the weight of the water that the ice displaces is greater than the weight of the ice itself. This is the principle of buoyancy. The difference in the two weights is the buoyant force acting on the ice. The same volume of water can have two different weights, if one is liquid and the other is solid [ice] because the density [weight per unit volume] of liquid water is greater than the density of ice. Water is one of the very few materials that exhibit this behavior. Earth is fortunate that water ice does expand and float. Just imagine what would happen if ice sank instead! All the water in the world would freeze and sink to the bottom of the oceans; the next bit of water would freeze and sink, too. In no time at all, earth would be nothing more than a spherical ice ball floating in space. [The late Isaac Asimov explored this far more eloquently that I just did in one of his many short science articles...] There are also about 9 different 'ices', called iceI, iceII, iceIII etc that are beyond the scope of your question. Ken
Try the links in the MadSci Library for more information on Chemistry.