Self-heating systems are technologies designed to generate heat without an external power source. These systems often use chemical reactions or phase change materials to produce warmth, making them useful in various applications, such as heating food or providing warmth in clothing. One common example of a self-heating system is the self-heating meal pack, which contains a chemical reaction that activates when water is added. This reaction generates heat, allowing the meal to cook itself without the need for a stove or microwave, making it convenient for outdoor activities or emergency situations.