Farmer Boy, Chapter 7

Expanding and Contracting
Almanzo observed, “It is odd that water swells when it freezes. Everything else gets smaller in the cold”. A common rule in chemistry is that heat expands and cold contracts. Most liquids follow this rule. As liquid cools, the molecules slow down so they can’t resist the natural desire to collect together.

Water molecules, however, don’t follow this rule. When water is cooled to the temperature of about 40 degrees it behaves as it should and contracts. But as it cools further, it begins to expand, and by the time it freezes it expands by approximately 9%. This expansion is what makes ice less dense than water, allowing it to float. God designed water in this way, because if water behaved as it should, following the contraction rule, many bodies of water would freeze solid in the winter, killing all the life within them.

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