done 6th Changes Around us

• question_answer1)
  In the given table, check whether the given change can be reversed or not.  

  Change	Can be reversed
  Raw egg to boiled egg
  Batter to idli
  Wet clothes to dry clothes
  Woollen yarn to knitted sweater
  Grain to its flour
  Cold milk to hot milk
  Straight string to a coiled string
  Bud to flower
  Milk to paneer
  Cow dung to biogas
  Stretched rubber band to its normal size
  Ice cream to molten ice cream

   
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• question_answer2)
  How the iron blade in these tools is fixed to the wooden handle?  
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• question_answer3)
  You have seen that construction workers heat a black material called coal tar, for repairing a road. State whether the change which has occurred in coal tar on being heated is reversible or irreversible?
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• question_answer4)
  How does a blacksmith change a piece of iron into different tools and what change has taken place in iron, on being heated?  
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• question_answer5)
  When salt dissolved in water, what change is happening at the end?
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• question_answer6)
  To walk through a waterlogged area, you usually shorten the length of your dress by folding it. Can this change be reversed?
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• question_answer7)
  You accidently dropped your favourite toy and broke it. This is a change you did not want. Can this change be reversed?a
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• question_answer8)
  Some changes are listed in the following table. For each change, write in the blank column whether the change can be reversed or not.  

  S. No.	Change	Can be reversed (Yes/No)
  (i)	The sawing of a piece of wood
  (ii)	The melting of ice candy
  (iii)	Dissolving sugar in water
  (iv)	The cooking of food
  (V)	The ripening of a mango
  (vi)	Souring of milk

   
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• question_answer9)
  A drawing sheet changes when you draw a picture on it. Can you reverse this change?
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• question_answer10)
  Give examples to explain the difference between changes that can or cannot be reversed.
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• question_answer11)
  A thick coating of a paste of Plaster of Paris (POP) is applied over the bandage on a fractured bone. It becomes hard on drying to keep the fractured bone immobilised. Can the change in POP be reversed?
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• question_answer12)
  A bag of cement lying in the open gets wet due to rain during the night. The next day, the sun shines brightly. Do you think the changes which have occurred in the cement, could be reversed?
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