Microwave heating is a method of cooking or warming food using electromagnetic waves. These waves, typically at a frequency of 2.45 gigahertz, excite water molecules in the food, causing them to vibrate and generate heat. This process allows food to cook quickly and evenly, making microwaves a popular choice in many kitchens. The technology behind microwave heating was discovered in the 1940s when Percy Spencer, an engineer, noticed that a candy bar melted in his pocket while working near a radar system. This led to the development of the first microwave oven, which has since evolved into a common household appliance.