A Dramatic Story about Water and Heat

This is not a story about firefighters. It's a story about oranges.

Citrus trees cannot stand cold. They start dying if the temperature drops below the freezing point of water.

Water, owing to the hydrogen bond, has a high heat capacity. It requires considerable energy to alter its temperature. Consequently, bodies of water help moderate the climate of surrounding land, maintaining temperatures within a relatively stable range. During the big freeze of 1895, almost all of Florida's citrus industry was decimated, with the notable exception of the orange groves around Keystone City, where there are a number of lakes. The city later changed its name to Frostproof.

In the book Oranges, the master storyteller John McPhee described this battle between citrus farmers and Arctic air. On a cold night, spraying water on trees to keep them warm may seem counterintuitive. However, that's the daring strategy employed by some ingenious growers during the 1962 freeze. Water releases heat when it freezes. As long as the sprayers stay on and the mixture of water and ice persists, the temperature around the trees stays at exactly 0°C, or 32°F. However, as more water is applied, the accumulating ice grows increasingly heavy. If the sun doesn't come up and thaw the ice before it becomes too heavy, the branches will break under the weight. Not all the growers won this race in 1962. Those who did woke up the next day and saw the price of their oranges triple.