Lesson RC 4-2 - Fires

Throw water on a fire in a wastebasket. What happens? It goes out. Now pour water on a drum of burning oil. This time, does the fire go out? No. It keeps burning.

Try to pour water on an electrical fire! What happens? You guessed it. Nothing. That is, if you don't step into the water! If you do something happens all right! You may get electrocuted.

Why does water put out some fires and not others? It depends on the fire. Water puts out fire by cooling it off. If you throw water on paper, it can't burn. It can't stay hot enough.

Pour water on burning oil, and something else happens. Oil floats on water. So the water sinks under the oil. And the oil keeps on burning. Many liquids that burn act like oil. That is, they float on water. So water is will not put out this type of fire. Don't try to put out a gasoline fire with water. You may just spread it instead.

The same goes for a grease fire. If grease in a pan catches fire, forget about water. It won't help. Toss salt on it instead. The salt soaks up the grease, and the fire goes out.

What about electrical fires? These usually start from bad wiring. Maybe a wire is worn through. Water is dangerous here. Electricity flows through water just like it flows through a wire. You can get killed if you pour water on an electrical fire. How do you put out an oil fire or an electrical fire? You get a special kind of fire extinguisher. The ordinary kind will not help because it sprays out water. You can't use it on burning oil. You can't use it on an electrical fire.

The special kinds of fire extinguishers don't use water. Some use a powder. Some use a gas. Both kinds put out a fire by cutting off the fire's air supply. Afire can't burn without air. You need a special extinguisher in a car repair shop. It will put out gasoline and oil fires. You also need a special extinguisher in a welding shop. It will put out electrical fires. Be sure you get the right kind. Look at the label on the extinguisher. It tells you what kind of fire it should be used on.

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Questions:

1. Which fire will water put out?

a. electrical fire
b. fire in a drum of oil
c. fire in a wastebasket

2. What happens when water is poured on burning oil?

a. the fire goes out
b. the oil floats on the water
c. the water catches fire

3. How do you put out an oil fire?

a. blow on it
b. pour water on it
c. use a special fire extinguisher

4. How does water put out a fire?

a. cools it
b. heats it
c. steams it

5. To put out a grease fire in a kitchen,

a. use butter
b. use salt
c. use water

6. The story says that if you pour water on an electrical fire, you may get

a. seriously injured
b. a bright flame
c. a medal from the fire department

7. What's in the special fire extinguishers?

a. oil or electricity
b. powder or gas
c. water

8. How can you tell what kind of fire a fire extinguisher is good for?

a. you can't tell
b. you guess
c. you read the label on the extinguisher

9. How do special fire extinguishers work?

a. make a loud noise
b. cut off the fire's air supply
c. sprays out water

10. A gasoline fire acts most like

a. an electrical fire
b. an oil fire
c. a paper fire

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