Microwaves are a form of electromagnetic radiation, specifically in the microwave frequency range. The source of microwave radiation is a device called a microwave oven. Microwave ovens generate microwaves using a component called a magnetron, which converts electrical energy into electromagnetic waves in the microwave frequency range. When you heat food in a microwave oven, the magnetron emits microwaves that are absorbed by water molecules in the food, causing them to vibrate and generate heat, thus heating the food. It's important to note that microwaves used in microwave ovens are designed to be contained within the oven and not leak out into the surrounding environment.