Water—An Extraordinary Substance
“AN EXTRAORDINARY substance. Anomalous [not what would naturally be expected] in nearly all of its physical-chemical properties,” say scientists. Are they talking about some newly discovered exotic chemical?
No. They are talking about ordinary water!
What makes water so special? The shape of the water molecule, for one thing. The two hydrogen atoms stick to the oxygen atom like the ears on a teddy bear, so the molecule is lopsided. This makes each water molecule act like a tiny magnet, with its negative pole down by the oxygen atom and its positive pole up around the hydrogen atoms.
If you magnetize things they can stick together, and so do water molecules. This gives water a high degree of “surface tension.” That is why water beads up on a smooth surface, forming little water mountains that seem to defy gravity. Try to get another liquid with less surface tension, such as rubbing alcohol, to do that!
Heat makes all molecules vibrate and separate from each other, but the “sticky” water molecules can absorb a great deal of heat without becoming “unglued,” that is, evaporating. Suppose you could take all the heat out of a block of ice and a block of gold—freezing them down to what is called absolute zero, 460 degrees below zero Fahrenheit (-273 degrees C). Now start heating up both the gold and the ice at the same rate. The same amount of heat raises the temperature of the gold much faster than that of the ice. When the gold melts, the ice is still “ice-cold” at 300 degrees below zero Fahrenheit (-184 degrees C)!
Because water can absorb so much heat we can be glad that it covers most of our planet. During the day a great deal of heat bombards the earth’s surface. At nightfall the heat supply is suddenly cut off. Such drastic changes every 24 hours could make life here miserable if the water in the oceans did not absorb most of the heat and gradually release it, moderating the sun’s effects.
The shape of the water molecule also affects the way it freezes, so that frozen water requires more space than liquid water—meaning that ice floats.
Imagine what would happen if water were not unusual in this respect. Every winter more and more ice would sink to the bottom of the oceans where the sun’s rays could not melt it the following summer. Soon the oceans might be frozen solid, except for a thin layer of water during the summers. With less water available for evaporation, the land areas would suffer drought. Little life would remain.
In many ways our lives depend on the unusual shape of the water molecule. Did it just happen that way? Or does it reflect the superior wisdom of a loving Creator?
[Picture on page 25]