Question

In a thermos flask cold liquids remains cold and hot liquids remains hot. how?

Answer 1

At first we have to know the methodes in which the heat is travel. (see the No.1 image)

In thermos flask
1. For the non conductive material heat can not pass through it.

2. For the vacuum heat can't transfer by Convection.

3. For the silver surface radiation of heat reflected.


Thush in thermos flask cold remains cold and hot , hot




hope it helps

Answer 2

Thermo flask contain two layers.Between them air is trapped.As we know that air is bad conductor of heat,it helps to keep cold and hot things.