Question

Explain how the different forms of heat losses are minimized in a thermos flask.

Answer 1

The thermos flask consists of a double-walled glass vessel resting on a cork inside a metal or plastic case. The outer surface of its inner wall and the inner surface of its outer wall are silvered. This prevents heat transfer due to radiation. The space between the two walls is almost vacuum and the walls are sealed at the top. The double-walled glass vessel and vacuum prevents heat loss by conduction. The insulating stopper or cork at the top minimizes heat loss by convection.