Question

(a) If you have to choose between two thin blankets and a thick blanket on a cold winter night, which one will you choose?

(b) Stainless steel pans are usually provided with copper bottoms. Why?

(c) You may have noticed that a few sharp jerks are given to a clinical thermometer before using it. Why is it done so?
[5 MARKS]

Answer 1

(a) Woolen clothes: 2 Marks
(b) Reason: 1 Mark
(c) Reason: 2 Marks

(a) We must choose two thin blankets instead of one thick blanket because woolen fibres trap air inside them, this air prevents the flow of heat from our body to the cold environment. When we have two thin blankets, there is a layer of air trapped between the blankets. It prevents the heat flow.

(b) Stainless steel pans are usually provided with copper bottoms because copper is a better conductor of heat than stainless steel.

(c) The jerk to the thermometer will allow the mercury in or above the kink to flow into the bulb so that the mercury level is below normal temperature.