Microwaves are electromagnetic rays with a frequency range of 0.3 GHz to 300 Ghz. They are found between the radio waves and the infrared waves in the electromagnetic spectrum. Microwave radiation is the radiating wave movement in which microwave energy travels.
This type of energy takes a straight line path. Like all electromagnetic waves, they do not require a medium to travel through. They can pass through non-metal materials like plastic and glass, but get reflected off metal surfaces. Microwaves are absorbed by foods and other materials with high water content, and produce heat. This is the operational principle on which microwave kitchen appliances work.
A microwave oven consists of a high voltage transformer, an electron tube called magnetron, a wave guide fan, and a cooking chamber. The transformer passes electric energy to the magnetron, which converts this electric energy into microwave radiation. The radiation is reflected in the cooking chamber and absorbed by the food.
As a result of the microwave absorption, the water molecules in the food begin to vibrate. This molecular movement produces heat, which cooks the food. Foods that have higher concentrations of water molecules cook faster. In thicker foods, the outer part is cooked by the microwaves and the inner part is cooked by conduction of heat from the heated outer part.
Concerns about microwaves turning food radioactive are baseless. The "radiation" refers to the way in which microwaves move, not radioactivity. Microwaves are of a non-ionizing character, which means that they do not have the energy to cause chemical changes in substances as would happen in the case of radioactivity.
The principle danger of microwaves is that body tissue can be affected in the same way that food is. They can cause burns, eye cataracts, and other injuries. It, however, would take high levels of energy for this to happen. The levels of radiation in kitchen appliances are fortunately very low.
Microwave radiation also stops as soon as an appliance is turned off. This means that the dangers of standing in front of the microwave oven are rather negligible. At the same time, it is important for cooks to take sensible precautions.
Before buying a microwave kitchen appliance, a shopper should make sure that it meets industry approved safety standards. He should read and follow the device's instructions before using it. Only bowls and vessels specifically designed for microwave oven use should be placed inside. People should also avoid heating water or other liquids in the oven, at least not for long periods. The oven door should also be kept shut when it is in operation.