Microwave ovens use microwaves to pass through insulation materials such as glass, ceramics and plastics, but do not consume energy, while food containing water, microwaves not only can not pass through, their energy will be absorbed by these characteristics. The microwave oven's shell is made of stainless steel and other metal materials, which can prevent microwaves from escaping from the furnace, so as not to affect people's health. Containers for food are made of insulation.
The heart of the microwave oven is a magnetron. The tube, called the magnetron, is a microwave generator that produces 2.45 billion microwaves per second of vibration. This invisible microwave can penetrate food up to 5cm deep, and the water molecules in the food also move, intense movement produces a lot of heat, so the food "boiled" cooked.