We use heat every day to cook our food, dry our clothes, manufacture things and even to keep ourselves warm.
Cook our food
Dry our clothes
All matter contains certain amounts of heat, whether it is hot or cold. When heat acts on matter, it changes the matter in many ways. For example, when ice gains heat, it melts and changes its state and shape. Understanding what is heat, its properties and its effect on matter around us is very useful in our everyday life. For example, a thermometer is used to measure temperature. A change in our body temperature can be used to indicate that our body is not functioning well, which means that we have a fever. This is because human body temperature is constant at 37°C. This is one of the examples of how the principle of expansion and contraction of matter can be put into good use.