Eli5: Why can a thermal flask keep items cold for 24 hours, but only hot for 12 hours.

Question

Eli5: Why can a thermal flask keep items cold for 24 hours, but only hot for 12 hours.

In: Physics

Answer 1

The science behind this is called thermodynamics.
When things have high energy they contain high heat which makes them hot. When they have low energy they are cold.
Energy like this always wants to flow from hot to cold. From high energy to low energy.
When something is already cold in the flask, for it to get warm, energy must flow from the flask into the cold item inside the flask. Flasks insulate from the outside so the heat flows very slowly in that direction.
When something is hot inside the flask, the energy flows must faster trying to leave the flask since the energy difference is greater.