特別推薦：“起電”是怎么回事    貓沙是誰發明的？

某倉庫發生火災，消防隊及時趕到，迅速投入撲救。可半小時過去了，消防車拉來的50立方米水仍未能將大火撲滅，當看到附近有只燒開水的大鍋爐時，消防隊員靈機一動，把大量熱水澆到烈火上，奇跡出現，僅用9分鐘火焰就被熄滅了。這是為什么呢？且看下文分解。

As we know, the common ways of putting out a fire are cooling, stifling, isolating and restraining. Why is hot water better than cold water in putting out a fire? When hot water is sprayed on a fire, it not only cools whatever is burning, but also reduces the oxygen surrounding it because of the steam created. Once the fire is out of oxygen, it will be quickly brought under control. These layers of steam make a large-scale stifling effect so that the fire is quickly extinguished.

Relevant data shows that when the steam in the air adds up to 35% or the oxygen in the air is reduced to 17%, the fire will go out. Even the largest fire will be extinguished. It is clear that putting out a fire with hot water is much better than using cold water. Research shows that using boiling water to put out a fire is five times better than using hot water, and ten times more effective than cold water. In tests, one liter of hot water per second had the same effect as 20 to30 liters of cold water per second. If using boiling water, five firefighters can finish the work of ten using cold water. Using hot water to put out fires is very useful and should be widely implemented, but when putting out the fire, people must be careful not to be scalded by the boiling water.

（北京林業大學通訊員黃典鈺供稿 英語點津 Annabel 編輯）