In which direction does heat flow?
From a hot area to a cold area
Heat flows from a hot body to a cold body. When two bodies, one hot and another cold, come in contact with each other, the fast moving molecules of the hot body collide with the slow moving molecules of the cold body. As a result, the kinetic energy of molecules of the hot body decreases and the body itself becomes cooler, whereas the kinetic energy of molecules of the cold body increases and the body become warmer.