Chapter 8
Fire: Friend and Foe
Question:1 What is fire, and how did early man react to it?
Answer: Fire is a natural phenomenon that provides heat and light, but early man did not know what it was. He must have seen the damage it could cause from lightning and volcanoes and was frightened of its power and danger.
Question:2 How do we understand fire scientifically today?
Answer: Fire is the result of a chemical reaction. When oxygen in the air combines with carbon and hydrogen in a fuel, a chemical reaction takes place. Energy in the form of heat and light is released in this process.
Question:3 What three things are needed to make fire?
Answer: The three things needed to make fire are fuel, oxygen, and heat.
Question:4 Give examples of fuels mentioned in the text.
Answer: Some examples of fuel are wood, coal, cooking gas, and petrol.
Question:5 How does oxygen help fire to burn?
Answer: Oxygen from the air combines with carbon and hydrogen in a fuel, which is essential for the chemical reaction that produces fire.
Question:6 Why do we need heat to start a fire?
Answer: Fuel and oxygen do not make fire by themselves. Heat is needed to raise the temperature of the fuel to its flash point or kindling temperature so that combustion can begin.
Question:7 What is the flash point of a fuel?
Answer: The flash point, or kindling temperature, is the particular temperature at which a fuel begins to burn.
Question:8 What does the saying "fire is a good servant but a bad master" mean?
Answer: It means that fire is very useful as long as it is kept under control, but it becomes very dangerous when it gets out of control.
Question:9 What are some common uses of fire in daily life?
Answer: Fire is used to cook food, warm homes in winter, and generate electricity.
Question:10 What are the dangers of uncontrolled fire?
Answer: Uncontrolled fire damages homes and shops, destroys vast areas of forest, and kills or injures hundreds of people each year.
Question:11 How can fire be put out by taking away fuel?
Answer: If a fire has no fuel to feed on, no burning can take place. Often, we let a fire die out by not adding more fuel.
Question:12 How can fire be extinguished by preventing oxygen from reaching it?
Answer: Small fires can be put out or smothered with a damp blanket or sack, which stops oxygen from reaching the burning material. Carbon dioxide is also used to extinguish fire by preventing oxygen from reaching the fuel.
Question:13 How can removing heat put out a fire?
Answer: By lowering the temperature of the burning material below its flash point, the fuel stops burning. For example, blowing on a candle or spraying water absorbs heat and extinguishes the fire.
Question:14 Why should water not be used on oil fires?
Answer: Water floats on oil and carries the burning oil with it, spreading the fire, which can be very dangerous.
Question:15 Why should water not be used on fires caused by electrical appliances?
Answer: The person spraying water may receive an electric shock and be killed.
Question:16 What is the best way to fight an electrical fire?
Answer: A carbon dioxide extinguisher is the best way to fight an electrical fire.
Question:17 How much money is spent each year on fighting fires and preventing them?
Answer: Millions of rupees are spent each year in fighting fires and in finding new ways to prevent fires from happening or getting out of control.
Question:18 How did people fight fires long ago?
Answer: Long ago, there were no firemen, so everybody became a firefighter. People formed human chains and passed buckets of water from a well or pond to the blaze.
Question:19 How do modern laws help reduce the risk of fire in buildings?
Answer: Laws about building construction ensure that space is left between buildings to reduce the fire risk. New buildings, especially public places, must follow fire prevention norms.
Question:20 What are fire brigades and what do they do?
Answer: Fire brigades are bands of firefighting workers with special equipment. They put out fires, cut off electricity, knock down dangerous walls, spray water, and bring fires under control.
Question:21 Why are firefighters trained in first aid?
Answer: Firefighters are trained in first aid so that they can help people suffering from burns or from the effects of smoke.
Question:22 How did the discovery of fire help early man?
Answer: The discovery of fire helped early man cope with nature better and gradually adopt a settled mode of life.
Question:23 How is fire worshipped in some parts of the world?
Answer: Fire is still worshipped in many parts of the world as a symbol of power, purity, and life-giving energy.
Question:24 What does the word 'smouldering' mean?
Answer: Smouldering means burning slowly without flame.
Question:25 What does the idiom “add fuel to the flames” mean?
Answer: It means saying or doing something that makes people react more strongly or fiercely.
Question:26 How can a fire be smothered using a blanket?
Answer: Covering a small fire with a damp blanket prevents oxygen from reaching the fire, which puts it out.
Question:27 How does carbon dioxide extinguish a fire?
Answer: Carbon dioxide does not allow oxygen to reach the burning material, which stops the chemical reaction and puts out the fire.
Question:28 How does water help put out a fire?
Answer: Water absorbs heat from the burning fuel, lowers the temperature below the flash point, and also cuts off the supply of oxygen, extinguishing the fire.
Question:29 What precautions should be taken when using water on fires?
Answer: Water should not be used on oil fires or electrical fires because it may spread the fire or cause electric shock.
Question:30 What is meant by ‘flash point’ or ‘kindling temperature’?
Answer: The flash point or kindling temperature is the particular temperature at which a fuel begins to burn.
Question:31 How can we take away one of the three things needed for burning to control fire?
Answer: Fire can be controlled by removing fuel, cutting off oxygen, or removing heat.
Question:32 Give examples of removing fuel to control a fire.
Answer: Not adding more wood or coal to a small fire lets it die out naturally.
Question:33 Give examples of removing oxygen to control a fire.
Answer: Smothering a fire with a damp blanket, sack, or using a carbon dioxide extinguisher.
Question:34 Give examples of removing heat to control a fire.
Answer: Spraying water on a fire or blowing on a small candle flame lowers the temperature below the flash point.
Question:35 What are the three main ways to control or put out a fire?
Answer: The three main ways are taking away fuel, preventing oxygen from reaching it, and removing the heat.
Question:36 How does fire serve as a “friend”?
Answer: Fire serves as a friend by providing heat, light, and the ability to cook food, warm homes, and generate electricity.
Question:37 How does fire act as a “foe”?
Answer: Fire acts as a foe when it becomes uncontrollable, causing death, injury, destruction of homes, shops, and forests.
Question:38 Why is it said that early man must have watched lightning and volcanoes before using fire?
Answer: Because early man observed the destructive power of natural fires and understood their potential danger, which made him cautious and fearful.
Question:39 How does fire help humans cope with nature?
Answer: Fire provides warmth, protection, and a means to cook food, which allowed humans to live in various climates and gradually adopt a settled life.
Question:40 Why is it important to train firefighters and have laws for fire safety?
Answer: It is important so that fires can be prevented, controlled efficiently, and people can be protected from burns, smoke, and other dangers associated with uncontrolled fire.
Answer by Mrinmoee
