Heat always flows between areas of temperature in which direction?

Heat always flows from areas of higher temperature to areas of lower temperature due to the second law of thermodynamics. This principle states that thermal energy naturally moves in the direction that increases the overall entropy of a system, which is typically from hot to cold. When a hot object comes into contact with a cold object, thermal energy is transferred from the hot object (where molecules have more kinetic energy) to the cold object (where molecules have less kinetic energy) until thermal equilibrium is achieved.

This flow of heat continues until both areas reach the same temperature, at which point the transfer of heat ceases. Understanding this fundamental concept is crucial for grasping thermal dynamics in various applications, including engine operation and efficiency. It clarifies how heat is managed and utilized in engines, leading to better designs and understanding of cooling systems.