A microwave oven, or simply a microwave, is a kitchen appliance that heats and cooks food by exposing it to microwaves.
Electromagnetic radiation is transmitted in waves or particles at different wavelengths and frequencies. This broad range of wavelengths is known as the electromagnetic spectrum. The spectrum is generally divided into seven regions in order of decreasing wavelength and increasing energy and frequency.
Microwaves are a form of electromagnetic radiation with frequencies ranging from about 3 billion cycles per second, or 3 gigahertz (GHz), up to about 30 trillion hertz (terahertz or THz) and wavelengths of about 30 centimeters (12 inches) to 3 millimeters (0.12 inches).
The microwaves are generated in a microwave by a device called a magnetron, which converts electricity from the power outlet into microwaves.
These microwaves are absorbed by water molecules present in food, which are rotated by the electric field from the microwaves. As these molecules rub against each other, they heat up, and then they heat up molecules around them.
How was the Microwave Invented?
Percy Spencer invented the first microwave oven after World War II from radar technology developed during the war. One day, Percy Spencer noticed that microwaves from an active radar set he was working on started to melt a candy bar he had in his pocket. This gave him the idea that a magnetron might be used to cook food.