Unit -5 playing with the fire

1. Read the extracts and answer the questions.

 

(1) One of our favourite festivals in India is Deepavali or Diwali, as it is known in the North. There is nothing to match the excitement when crackers go off in the night sky with a loud bang and a brilliant shower of colours. Many of us might wonder how these fireworks are made, and what goes into them. The physics and chemistry of fireworks is as interesting as the sound and the light they emit.

1) Nothing can match the excitement when ………

Ans. Nothing can match the excitement when crackers go off in the night sky with a loud bang and a brilliant shower of colours.

2) The physics and chemistry of fireworks is as interesting as ………

Ans. The physics and chemistry of fireworks is as interesting as the sound and the light they emit.

       

(2) The science of fireworks is technically called, ‘pyrotechnics’ – from the Greek word ‘pyr’ meaning fire and ‘technics’ meaning an art. Pyrotechnics includes not only fireworks but also a whole range of devices that use similar materials and principles, from safety matches that we use every day to solid fuel rocket boosters of the space shuttle. The household match is considered a special pyrotechnic device, as all the pyrotechnics effects – heat, smoke, light, gas and sound – are present in it.

1) What is pyrotechnics?

Ans. Pyrotechnics is the science of fireworks.

2) What does the word ‘pyr’ mean?

Ans. The word ‘pyr’ means fire.

3) What does pyrotechnics include?

Ans. Pyrotechnics includes not only fireworks but also a whole range of devices that use similar materials and principles, from safety matches to solid fuel rocket boosters of the space shuttle.

4. Why is the household match a special pyrotechnic device?

Ans. The household match is a special pyrotechnic device because all the pyrotechnics effects – heat, smoke, light, gas and sound – are present in it.

5. Which are the different pyrotechnics effects in a household match?

Ans. The different pyrotechnics effects in a household match are: heat, smoke, light, gas and sound.

(3) Some historians say that ‘black powder’, the basic material used in fireworks, was invented in India. Shukranti, written more than two thousand years ago, has references to weapons similar to guns and projectile weapons.

Which is the basic material used in fireworks?

Ans. The basic material used in fireworks is black powder.

Shukranti has references to ………

Ans. Shukranti has references to weapons similar to guns and projectile weapons.

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(4) However, the Chinese are generally considered the pioneers of pyrotechnics. They are said to have developed ‘black powder’ more than one thousand years ago. It took at least two hundred years for the knowledge to spread to the west, and it was only in 1242 that an English monk, Roger Bacon, revealed the formula for “black powder”. He considered it such a dangerous substance that he wrote of it in a code language.

Who are said to be the pioneers of pyrotechnics?

Ans. The Chinese are said to be the pioneers of pyrotechnics.and principles, from safety matches to solid fuel rocket boosters of the space shuttle.

2. Who developed black powder? When?

Ans. The Chinese developed black powder more than one thousand years ago.

3. Who revealed the formula for black powder? When?

Ans. Roger Bacon, an English monk, revealed the formula for black powder in 1242.

4. Why did Roger Bacon write about black powder in code language?

Ans. Roger Bacon wrote about black powder in code language because he considered it a very dangerous substance.

5. What was Roger Bacon’s opinion about black powder?

Ans. According to Roger Bacon, black powder was a very dangerous substance.

(5) The basic formula of the black powder, or gun powder, has remained unchanged for centuries. It is a blend of potassium nitrate, charcoal and sulphur in the ratio of 75:15:10 by weight. It is almost the perfect combination as it is and no further improvements or alternations need be made. Experts say that this might be the only chemical product still using the same age-old proportions and manufacturing techniques.

………. has remained unchanged for centuries.

Ans. The basic formula of black powder has remained unchanged for centuries.

3) What is the formula for black powder?

Ans. Black powder is a blend of potassium nitrate, charcoal and sulphur in the ratio of 75:15:10 by weight.

2) What do the experts say about the formula of black powder?

Ans. Experts say that black powder might be the only chemical product still using the same age-old proportions and manufacturing techniques.