Chapter 8: Fire: Friend and Foe

(From NCERT Honeycomb, Class 7 English)

Genre: Informative Article

Story Overview (Key Concepts)

"Fire: Friend and Foe" is an informative chapter that explores the dual nature of fire. It discusses the history of fire, how it is produced, its various uses, and the devastating dangers it poses when uncontrolled. The chapter also explains the "fire triangle" (fuel, oxygen, heat) and the different ways to extinguish fires by removing one or more of these elements. It highlights the evolution of firefighting techniques and the importance of fire brigades.

Detailed Summary

The Discovery and Early Uses of Fire

Early humans were initially puzzled and frightened by fire, probably witnessing its destructive power in lightning strikes and volcanoes. However, they soon discovered that fire could be useful. It provided warmth, cooked food, and offered protection from wild animals. The discovery of fire and its controlled use was a major step in human evolution, helping primitive humans cope with cold weather and establish settlements.

What is Fire? The Fire Triangle

Fire is the result of a **chemical reaction** where three things are necessary: **fuel, oxygen, and heat**. This concept is often called the **'fire triangle'**. Fuel can be anything combustible like wood, coal, gas, or oil. Oxygen comes from the air. Heat is needed to raise the temperature of the fuel to its ignition point (flash point), the lowest temperature at which a substance will catch fire. Removing any one of these three elements will extinguish the fire.

Fire as a Friend: Uses of Fire

For thousands of years, fire has been our constant companion. It is used in daily life for:

Without fire, our lives would be very different and much more difficult.

Fire as a Foe: Dangers of Uncontrolled Fire

While useful, fire can be a dangerous foe when it gets out of control. Every year, thousands of homes and shops are destroyed, and vast tracts of forest are ruined by fire. Many people are killed or injured. Firefighting has evolved significantly over time, from primitive bucket brigades to modern, well-equipped fire brigades.

Methods of Extinguishing Fire

The three main ways to put out a fire correspond to removing one of the sides of the fire triangle:

  1. Removing the fuel: If there's no fuel, a fire cannot burn. For example, by turning off a gas supply or letting a fire burn out of its own accord if the fuel is limited.
  2. Cutting off the oxygen supply: If a fire doesn't get oxygen, it will die. This can be done by blanketing the fire with a damp blanket, sand, or a fire extinguisher. Covering a small fire with a lid also cuts off oxygen.
  3. Reducing the heat: Lowering the temperature below the ignition point will extinguish the fire. The most common way to do this is by spraying water on the fire. Water cools the combustible material, and its steam also helps cut off oxygen.

It's important to note that **water cannot be used on electrical fires or oil/petrol fires**. Water conducts electricity, posing a risk of electrocution, and it floats on oil, spreading the fire further. For these types of fires, carbon dioxide (CO2) extinguishers are used as they cut off oxygen without being electrically conductive or spreading liquid fuels.

Firefighters and Fire Brigades

The development of fire brigades, with trained firefighters and specialized equipment like fire engines, is a modern solution to fighting fires. Firefighters are highly skilled individuals who know how to cut off fuel supply, put out fires, and provide first aid. Their primary job is to control and extinguish fires, but they also prevent fires and provide assistance during other emergencies.

Building codes are established to ensure fire prevention measures like minimum safety standards and fire exits. The discovery and control of fire were crucial for human development, leading to settled life and industrialization. While a powerful force, fire needs to be managed carefully to remain a friend and not become a foe.

Key Aspects of Fire

Word Meaning
SmoulderingBurning slowly with smoke but no flame
DevastatingHighly destructive or damaging
AncestorA person, typically one more remote than a grandparent, from whom one is descended
Ignition PointThe lowest temperature at which a combustible material will spontaneously ignite in normal atmosphere without an external source of ignition, such as a flame or spark
Flash PointSimilar to ignition point, but specifically the lowest temperature at which a liquid gives off enough vapor to form an ignitable mixture with air near the surface of the liquid
BlazeA very large or fiercely burning fire
SmotherCover (something) entirely with a substance so as to prevent air from reaching it and thus extinguish it
Starve (a fire)To deprive a fire of its fuel, thus putting it out
BandageA strip of material used for binding up a wound or other injury
BrigadeA unit of an army; here, a fire brigade (a team of firefighters)
CombustibleAble to catch fire and burn easily
ElectrocutionInjury, execution, or death by electric shock
HazardousRisky; dangerous
Erupt(Of a volcano) become active and eject lava, ash, and gases; (of a fire) break out suddenly
TameBring (an animal or person) under control and domesticate it; to control something wild or dangerous
UnrulyDisorderly and difficult to control
FirescapeA metal staircase or ladder on the outside of a building, allowing escape from a fire (often called fire escape)
InflammableEasily set on fire; flammable (the words have the same meaning)

NCERT Textbook Questions & Answers

Working With The Text

  1. What is fire? What are the three things needed to make fire?

    Fire is a chemical reaction that produces heat and light. The three things needed to make fire are **fuel, oxygen, and heat**.

  2. There are three main ways in which a fire can be put out. Give one example for each.

    (i) **Removing the fuel:** For example, by turning off the gas supply to a burning stove. (ii) **Cutting off the oxygen supply:** For example, by throwing a damp blanket over a small fire or using a CO2 extinguisher. (iii) **Reducing the heat:** For example, by spraying water on a burning piece of wood to cool it below its ignition point.

  3. Match the items in Box A with those in Box B.
    Box A Box B
    (i) To burn wood, coal, charcoal(c) We need heat.
    (ii) Blazing fire(d) Can be put out by starving it.
    (iii) To make a fire extinguisher(e) Carbon dioxide is used.
    (iv) Blanket of foam or sand(b) Does not allow oxygen to reach the burning material.
    (v) A good firefighter(a) Has technical knowledge about fighting fire.

    (Table above shows the correct matches.)

  4. What are some of the things you should do when a fire breaks out in your house?

    When a fire breaks out in the house, one should:
    (i) Stay calm and call the fire brigade immediately (101 in India).
    (ii) Try to put out a small fire using a fire extinguisher, sand, or a damp blanket if it's safe to do so.
    (iii) If the fire is large, evacuate the house quickly and safely.
    (iv) Do not use water on electrical or oil fires.
    (v) Help others, especially children and the elderly, to get out.

  5. Do you think the author has used the phrases “friend and foe” appropriately? Give reasons.

    Yes, the author has used the phrases "friend and foe" very appropriately. Fire is a **friend** because it has been invaluable to humans for warmth, cooking, generating power, and various industrial processes, making life comfortable and productive. However, it is a **foe** because, when uncontrolled, it can be extremely destructive, causing immense damage to property and loss of life. The chapter effectively highlights both its beneficial and destructive aspects, justifying the title.

Working With Language

  1. Read the following sentences.

    To start a fire, we need fuel, oxygen and heat. (simple sentence)

    We can have a fire if we have fuel, oxygen and heat. (complex sentence)

    We can have a fire, and we can also put it out. (compound sentence)

    Write five sentences about "Fire" and classify them as simple, complex, or compound.

    (i) **Fire is a useful servant but a bad master.** (Simple sentence) (ii) **If you throw water on a fire, you will cool it down.** (Complex sentence) (iii) **Fire gives us warmth, and it helps us cook.** (Compound sentence) (iv) **People learned to control fire thousands of years ago.** (Simple sentence) (v) **Although fires are dangerous, they are essential for modern life.** (Complex sentence)

  2. Fill in the blanks in the following sentences with words from the box.
    • carbon dioxide
    • smother
    • blaze
    • ignition point
    • smouldering
    • firemen
    1. To help fires **smoulder**, we add chemicals to them.
    2. Small fires can be put out with a damp blanket to **smother** them.
    3. Fires can be extinguished by cutting off the fuel supply or by reducing the **ignition point** of the fuel.
    4. The **blaze** was so hot that the neighbours watched in amazement.
    5. Huge quantities of **carbon dioxide** are used to fight electrical fires.
    6. **Firemen** put out fires by cutting off the fuel supply.

    (Answers filled directly into the blanks above.)

Extra Questions & Answers

Short Answer Questions (30-40 words)

  1. How did early humans react to fire? What did they discover about it?

    Early humans were likely frightened by fire initially, observing its destructive power in nature. However, they soon discovered that fire could provide warmth, cook food, and protect them from wild animals, realizing its immense utility.

  2. Explain the term "flash point" or "ignition point."

    The "flash point" or "ignition point" refers to the lowest temperature at which a substance will begin to burn. Before a fuel can catch fire, its temperature must be raised to this specific point.

  3. Why is water not suitable for putting out electrical fires?

    Water is not suitable for putting out electrical fires because it is a good conductor of electricity. Using water could result in an electric shock to the person trying to extinguish the fire, or it could spread the electrical current further, making the situation more dangerous.

  4. What is the role of a fire brigade?

    The role of a fire brigade is to put out fires, control them, and save lives and property. Besides fighting fires, they also offer advice on fire prevention, help people stuck in emergencies, and provide first aid.

  5. How have building codes helped in fire prevention?

    Building codes have helped in fire prevention by establishing rules and regulations for construction. These codes ensure that buildings are constructed with adequate fire exits, proper ventilation, and fire-resistant materials, thereby reducing the risk of fire spreading rapidly and enabling safer evacuation.

Long Answer Questions (80-100 words)

  1. Describe the 'fire triangle' and how understanding it helps in firefighting.

    The 'fire triangle' explains that three elements are essential for fire to exist: fuel, oxygen, and heat. Fuel is any combustible material. Oxygen, usually from the air, sustains the burning. Heat brings the fuel to its ignition point. Understanding this triangle is crucial for firefighting because if any one of these three elements is removed, the fire will go out. Firefighters use this principle by either 'starving' the fire (removing fuel), 'smothering' it (cutting off oxygen), or 'cooling' it (reducing heat with water or other agents). This scientific understanding allows for effective and targeted fire control methods.

  2. Discuss the importance of fire in human civilization.

    The discovery and control of fire were pivotal moments in human civilization. Fire enabled early humans to survive colder climates, offering warmth and protection from wild animals, which facilitated migration and settlement in diverse regions. It revolutionized diet by allowing for the cooking of food, making it more digestible and safer. Beyond survival, fire became fundamental to developing industries, shaping tools, and providing light, significantly improving quality of life. Without the ability to harness fire, the advancement of human societies, from primitive communities to modern industrial civilizations, would have been severely limited, making it an indispensable tool and friend throughout history.

  3. Why is it important to have organised fire brigades and strict fire-fighting laws today?

    It is crucial to have organized fire brigades and strict fire-fighting laws today because, despite its benefits, fire remains a destructive force if uncontrolled. Urbanisation and complex infrastructure mean fires can cause massive damage to property and loss of life in densely populated areas. Organized fire brigades with trained personnel and modern equipment can respond quickly, efficiently containing fires and performing rescues. Strict fire-fighting laws and building codes ensure preventative measures like fire safety standards, proper exits, and fire-resistant materials are in place. These measures collectively minimize fire hazards, protect lives, and prevent widespread economic and social devastation.

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