Microwave ovens use microwaves can pass through glass, ceramics, plastics and other insulating materials, but does not consume energy; and food containing water, microwave not only can not pass through, its energy will be absorbed instead of these characteristics of the production. Microwave oven shell made of stainless steel and other metal materials, can block the microwave escape from the oven, so as not to affect people's health. The containers for the food are made of insulating materials. The heart of the microwave oven is the magnetron. This is called the magnetron tube is a microwave generator, which can produce microwaves with a vibration frequency of 2.45 billion times per second. This invisible microwave, can penetrate the food up to 5cm deep, and make the food in the water molecules also followed the movement, the violent movement produced a lot of heat, so the food cooked.