How is convection prevented in thermos flask?

Answer 1

A glass thermos 'bottle' is constructed as a bottle-within-a-bottle and there is a slight vacuum between the bottles, since heat can't travel within a vacuum it will keep the contents hot/cold for a long time. In addition, they usually have a mirror coating on the outside to reflect hot/cold from the environment. The cap usually is hollow with an insulating material like cork or poly-foam.

Answer 2

The heat transfer in a thermos flask is minimised because of the two layers of glass there are inside a thermos flask. Its a bit like a bottle inside a bottle. They are coated with a silvery type substance which radiates the heat back into the liquid/ whatever you have in the flask.

Btw im in year eight but im right coz we are doing this in our science lessons and also its my homework so i should know.

Answer 3

The thermos flask is basically two flasks, one in side the other, in between the two flasks a vacuum is produced. Convection requires a liquid or a gas to transfer heat, therefore it can't happen in a vacuum.

Its seal makes a Vacuum in the flask stopping heat from escaping

Answer 4

because there is no where for the heat to escape like when you have your tea on a plate it will soon go cold because the heat can escape

a flask stops heat escaping by stopping convection conduction and radiation

the heat doesnt escape because the lid is air tight so evaporation cant happen

Answer 5

heat loss occurs in three ways,by conduction,convection and radiation.these 3 means of heat loss are prevented in a thermos flask.the inside of the flask is coated by silver,which causes the reflection of heat waves and thus prevent its loss.also the space between the outer and inner walls of the flask is filled with a thermal insulator which prevents conduction.

Answer 6

In a thermic flask there is two layers in between there is vacume and no radaition from out side to inside the flask. So any thing inside the flask remain with out change in its temrature.