| Heat always flows from a warmer substance to a colder substance |
| Each substance consists of a mass of moving molecules. The fast moving molecules of a warmer substance give up a part of their energy to the molecules which are slower and have less heat. This slows down the molecular movement of the warmer substance and the molecular movement of the colder substance is accelerated. This happens until the molecules of both substances move with the same speed. Then they have the same temperature and no further heat exchange takes place. |
|
|
|
