Why do bubbles appear when a liquid is heated?
When liquid is the heated formation of vapours takes place which appears in the form of bubbles.
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 airtight till it cooled down to room temperature. (a) Why did the tiny bubbles appeared? (b) Do you think tiny bubbles will appear on heating the water taken out from the bottle? Justify your answer
Why is heat given out when a vapour condenses into a liquid ?