There is an interesting molecule, commonly called water which makes up most of our bodies and is instrumental to the operation of the biosphere.  The molecule is composed of three atoms: an oxygen and two hydrogens.  The hydrogens are attached to the oxygen at an angel of about 118 degrees.  I am pulling that out of my memory bank, so won’t certify its accuracy.  The electrons around these atoms are pulled slightly to the side that the hydrogens occupy and provide a positive charge there and a negative charge near the oxygen.  The oxygen atom attracts additional association with hydrogens, but not a bond like with its molecule.  As every molecule is attracted to every other one, water tends to be a rather associative compound.  We did an experiment in chemistry: take a penny, use an eye dropper and count how many drops of water you can place on the penny.  It’s rather impressive.

When water gets cold, it turns to ice.  In actual practice, there is additional movement that happens because the atoms associate this time with groups of 6 other molecules and force a shape in a more definite pattern than is known in the liquid state.  This pattern lowers the density of the water meaning it requires more space than the liquid water takes.  A lower density is what lets ice float.  The liquid water is denser and stays under the lighter, less dense ice.

What you see above the water is about 1/8 of the piece of ice.  The dimensions from the water line to the bottom of the ice will equal the amount of water displaced of a weight equal to the entire piece of ice.  In other words, when the ice melts, it will occupy the space displaced by the bottom 7/8 of the ice.  If you think about it in that fashion it becomes easy to see that melting ice will never raise or lower the level of the water in which it floats because it displaces the amount of water equal to its weight.

Remember this the next time someone tells you about melting ice flooding our cities.  It can’t.   The only place where the ice is on the land (and hence not floating) is Antarctica, and there is no melting there.  The ice is actually getting thicker, whether the greenies in their stuck ship think so or not…