(NCERT Page 118)
- Mark the correct answer in each of the following.
(i) Early man was frightened of
(a) lightening and volcanoes.
(b) the damage caused by them.
(ii) (a) Fire is energy.
(b) Fire is heat and light.
(c) Fire is the result of chemical reaction.
(i) (c) fire
(ii) (c) Fire is the result of chemical reaction.
- From the boxes given below choose the one with the correct order of the following sentences.
(i) That is fire.
(ii) A chemical reaction takes place.
(iii) Energy in the form of heat and light is released.
(iv) Oxygen combines with carbon and hydrogen.
(i) (i) (iii) (iv)
(ii) (iii) (i) (iv)
(iv) (iii) (ii) (i)
(iv) (ii) (iii) (i)
Ans. (iv) (ii) (iii) (i)
Working with the Text
(NCERT Pages l19 and 120)
Answer the following questions.
- What do you understand by the ‘flash point’ of a fuel?
Ans. Every fuel catches fire at a particular temperature. This temperature is called the ‘flash point’ of a fuel.
- (i) What are some common uses of fire?
Ans. Fire is used in cooking, to keep our homes warm during winter. Fire is also used to produce electricity.
(ii) In what sense is it a ‘bad master’?
Ans. If fire goes out of control, it can cause damage to our life, house and property. It is ‘bad master’ in this sense.
- Match items in Column A with those in Column B.
(i) fuel – lighted matchstick
(ii) oxygen – air
(iii) heat – coal
– burning coal
– smouldering paper
– cooking gas
Ans. (i) fuel – coal
– burning coal
– smouldering paper
– cooking gas
(ii) oxygen – air
(iii) heat – lighted matchstick, burning coal.
- What are the three main ways in which a fire can be controlled or put out?
Ans. Fire can be put out by taking away the fuel, stopping the supply of oxygen or by lowering down the temperature around the fuel, so that the fuel is not able to attain its flash point.
- Match the items in Box A with those in Box B
|(i)||To burn a paper or a piece of wood||it absorbs heat from the burning material and lowers the temperature|
|(ii)||Small fires can be put out||reduces the risk of fire|
|(iii)||When water is spread on fire||with a damp blanket|
|(iv)||A carbon dioxide extinguisher is the best thing||we heat it before it catches fire|
|(v)||Space left between buildings||to put out an electrical fire|
|(i)||To burn a paper or a piece of wood||we heat it before it catches fire it|
|(ii)||Small fires can be put out||with a damp blanket|
|(iii)||When water is spread on fire||it absorbs heat from the burning material and lowers the temperature|
|(iv)||A carbon dioxide extinguisher is the best thing||to put out an electrical fire|
|(v)||Space left between buildings fire||reduces the risk of fire|
- Why does a burning candle go out when you blow on it?
Ans. When we blow a burning candle, we disturb the hot air around and reduce down its temperature. The temperature comes below the flash point and the candle stops burning.
- Spraying water is not a good way of putting out an oil fire or an electrical fire. Why not?
Ans. Oil is lighter than water. It floats over it and continues to burn. So, water cannot be used to put
out oil fires. Moreover, as the water spreads, it carries along with it the oil as well, further increasing the chance of spreading the fire.
Water is a good conductor of electricity. So, when water is sprayed over electrical fire there are extreme chances of it conducting the electricity. It can result in causing shock and severe injury to the person fighting the fire.
- What are some of the things you should do to prevent a fire at home and in the school?
Ans. Buildings should be constructed at a distance to reduce the risk of catching fire. There should be suitable precautions and extinguishing devices be kept at home and schools to prevent fire.
Working with Language
(NCERT Pages 120 to 122)
- Read the following sentences.
To burn paper or a piece of wood, we heat it before it catches fire. We generally do it with lighted match. Every fuel has a particular temperature at which it burns.
The verbs in italics are in the simple present tense. When we use it, we are not thinking only about the present. We use it to say that something happens all the time or repeatedly or that something is true in general.
Find ten examples of verbs in the simple present tense in the text ‘Fire: Friend and Foe’ and write them down here. Do not include any passive verbs.
Ans. (i) Fire is the result of a chemical reaction
(ii) This is what we call fire.
(iii) To burn a piece of paper or wood, we heat it before it catches fire.
(iv) Oxygen comes from the air.
(v) It is sometimes said that fire is a good servant, but a bad master.
(vi) The third way to putting out a fire is to remove heat.
(vii) We spend millions of rupees each year in fighting fire.
(viii) It absorbs heat from burning fuel.
(ix) It only means that fire is very useful.
(x) Fire is still worshipped in many parts of the world.
- Fill in the blanks in the sentences below with words from the box. You may use a word more than once.
carbon cause fire smother
(i) Gandhiji’s life was devoted to the …………………. of justice and fair play.
(ii) Have you insured your house against ………………….?
(iii) Diamond is nothing, but …………………. in its purest form.
(iv) If you put too much coal on the fire at once you will …………………. it.
(v) Smoking is said to be the main …………………. of heart disease.
(vi) When asked by an ambitious writer whether he should put some …………………. into his stories. Somerset Maugham murmured, “No, the other way round”.
(vii) She is a …………………. copy of her mother.
(viii) It is often difficult to …………………. a yawn when you listen to a long speech on the value of time.
Ans. (i) cause (ii) fire
(iii) carbon (iv) smother
(v) cause (vi) fire
(vii) carbon (viii) smother
- One word is italicised in each sentence. Find its opposite in the box and fill in the blanks.
|spending shut destroy subtract increase|
(i) You were required to keep all the doors open, not ………………….
(ii) Pupil: What mark did I get in yesterday’s Maths test?
Teacher: You got what when you add five and five and …………………. ten from the total?
(iii) Run four kilometers a day to preserve your health. Run a lot more to …………………. it.
(iv) If a doctor advises a lean and lanky patient to reduce his weight further, be sure he is
doing it to …………………. his income.
(v) The world is too much with us; late and soon.
Getting and …………………. we lay waste our powers.
Ans. (i) shut (ii) subtract
(iii) destroy (iv) increase
- Use the words given in the box to fill in the blanks in the sentences below.
|across, along, past, through|
(i) The cat chased the mouse …………………. the lawn.
(ii) We were not allowed to cross the frontier. So, we drove …………………. as we could and came back happy.
(ii) The horse went …………………. winning post and had to be stopped with difficulty.
(iv) It is not difficult to see …………………. your plan. Anyone can see your motive.
(v) Go …………………. the yellow line, then turn left. You will reach the post office in five minutes.
Ans. (i) across (ii) along (iii) past
(iv) through (v) along
Speaking and Writing
(NCERT Page 122)
- Look at the following three units. First re-order the items in each unit to make a meaningful sentence. Next, re-order the sentences to make a meaningful paragraph. Use correct punctuation marks in the paragraph.
(i) and eighteen fire tenders struggled/the fire began on Monday/to douse the blaze till morning
(ii) in a major fire/ over 25 shops/were gutted
(iii) but property/was destroyed/worth several lakhs/no causalities were reported.
Ans. (i) The fire began on Monday and eighteen fire tenders struggled to douse the blaze till morning.
(ii) Over 25 shops were gutted in a major fire.
(iii) No causalities were reported, but properties worth several lakhs were destroyed.
- Read the following newspaper report given in the box below.
|Fire Station Goes Up in Flames
A fire chief was embarrassed when a station without a smoke alarm went up in flames. The building and a fire engine were destroyed in the blaze. Nobody was injured in the fire that was tackled by 30 firefighters in six fire engines from neighbouring towns.