Fire friend and foe summary
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SUMMARY OF THE LESSON
Fire is a necessary evil. It is a boon as well as a curse. It has made our life comfortable, but we cannot touch it. It was the first great invention made by early man.
Early man didn't know how to make fire. But he must have seen the destructive power of fire. He must have watched lightning and volcanoes. He was afraid of it. What is fire? Fire is, in fact, the result of a chemical reaction. The air has oxygen, while fuels have carbon and hydrogen. When the two combine, energy is released in the form of heat and light. This is what we call fire.
Three things are needed to make fire-fuel, oxygen and heat. The common fuels are wood, coal, gas and petrol. Oxygen comes from the air. That is why, when we blow on burning paper, it bursts into flame. Fuel and oxygen do not make fire themselves. They need heat. A lighted match provides that heat. Every fuel begins to burn at a particular temperature.
Fire is a good servant but a bad master. It is useful as long as it is under control. The moment it becomes out of control, it spreads havoc. Every year thousands of homes and trees are damaged by fire. Forest fire destroys trees and kills people
Fire can be put out in three ways. We can take away the fuel, or stop oxygen from reaching the burning material. The third way is to bring down the temperature below the flash point. Remove the hot air around the burning candle, and it will go out. Water also lowers the temperature and puts out the fire.
Some fires cannot be put out with water. Oil fire is one such example. The oil floats to the top of water and continues to burn as well as spread. Electrical fire also can't be controlled with water. It is fought by using carbon dioxide.
On the whole, we have learnt well to control fire and make good use of it in everyday life. Long ago there were no firemen. The people used to bring and throw bucketfuls of water on the flames. Now there are laws to stall fire extinguishers in every big building. There are fire brigades in every town. Trained fire fighters use their skills like cutting off power supply, pulling down weak walls and spraying water to bring fire under control. They are also trained to provide first aid to injured people.
Fire is still worshipped in many parts of the world. It helped early man to keep off animals and settle down in safe places.