Question

3.
Give reasons for the following:
a) A puri swells up when put in hot oil.
b) A new quilt feels warmer than an old one.
c) Firefighters and race car drivers wear special shiny suits.
d) During a fire breakout, you are advised to crawl on the floor towards the exit.
e) It saves fuel if we cook food in a vessel which is blackened at the bottom and polished from the sides.
1) Birds puff up their feathers in winter.
g) Two thin woollen sweaters are warmer than a thick woollen sweater.​

Answer 1

Answer:

A new quilt is warmer because the air which is trapped inside the cotton or woollen clothing acts as an insulator and does not allow the transfer of heat. However, when the quilt gets older, the air spacing of the cotton or wool gets compressed it no longer remains a good insulator. Hence, the person does not feel warm.