This means:
* When a warm object touches a cool object, heat will flow from the warm object to the cool object.
* The warm object will lose heat and cool down, while the cool object will gain heat and warm up.
This is a fundamental principle of thermodynamics known as the second law of thermodynamics.
Think of it like this: imagine a hill with water flowing down it. The water naturally flows from the higher point (higher temperature) to the lower point (lower temperature) until the water level is even. Similarly, heat energy will flow from the warmer object to the cooler object until they reach a thermal equilibrium.
