Self-heating refers to a process where an object generates heat without an external energy source. This phenomenon can occur in various materials, such as certain types of chemical compounds or food products. In self-heating food, for example, a chemical reaction is triggered when the packaging is activated, allowing the meal to warm itself. This technology is often used in military rations and emergency food supplies, providing a convenient way to heat meals in situations where traditional cooking methods are unavailable. Self-heating systems are designed to be safe and efficient, making them popular for outdoor activities and disaster preparedness.