Microwave ovens use microwaves, which are a type of electromagnetic wave. Microwaves have a wavelength ranging from approximately 1 millimeter to 1 meter and correspond to frequencies between 300 megahertz (MHz) and 300 gigahertz (GHz). These waves fall between radio waves and infrared waves in the electromagnetic spectrum. In microwave ovens, these waves are generated by a device called a magnetron, which converts electrical energy into microwaves. These microwaves are then used to heat and cook food by causing water molecules in the food to vibrate, generating heat.