Page 36 - Curriculum Visions Dynamic Book

Putting out fires
Water is noncombustible, which means that it will not catch fire. When the water is heated, the oxygen will not separate from the hydrogen in the water molecule, and so it will not provide more oxygen to fuel the flames. Instead, the water changes state from liquid
to gas, and heat is lost in the air. Because the water
is held together with hydrogen bonds, the energy required to vaporise the liquid is particularly high, and so extra heat energy has to be transferred from the burning material to cause vaporisation.
At the same time, water, with its high thermal capacity, is very effective at lowering the temperature of a fire, often below the combustion point of the
(Below) Automatic fire extinguishers are set off by an increase in air temperature. Water is jetted out to douse flames before they become difficult to control.
(Right) Fires can be put out with a variety of substances; but water is not only abundant and cheap, it is also particularly effective.
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