How do microwaves work?

Microwaves work by emitting electromagnetic radiation that is absorbed by food, causing it to heat up. The energy is produced by a device called a magnetron, which converts high-voltage electric energy into microwave radiation. The microwaves are then directed into the cooking compartment of the oven, where they bounce off the metal walls and are absorbed by the food. The microwaves excite the water, fat, and sugar molecules in the food, causing them to vibrate rapidly and generate heat.

Because the microwaves only penetrate about an inch into the food, the heat is generated from the inside out, unlike conventional ovens which cook from the outside in. This allows food to cook much faster and more evenly. To prevent the microwaves from escaping the oven and causing harm, the door of the microwave is designed to be airtight and made of metal, which reflects the microwaves back into the oven.