Paheli kept some water in a beaker for heating. She observed that tiny bubbles appeared before the water started to boil. She boiled the water for about 5 minutes and filled it in a bottle up to the brim and kept the bottle air-tight till it cooled down to room temperature.

(a) Why did the tiny bubbles appear?


(b) Do you think tiny bubbles will appear on heating the water taken out from the bottle? Justify your answer.


(a) Tiny bubbles were formed/appeared because the air dissolved in the water start escaping in the form of tiny bubbles on boiling.


(b) No, there will be no tiny bubbles because there is no dissolved air left in the water.


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