Unlike conventional ovens, a microwave oven heats food without applying external heat. A magnetron tube is used to produce short electromagnetic waves known as microwaves, or R. F. energy.
Microwave energy is directed into the cooking chamber where the food is placed to be heated.
The microwaves readily pass through many materials, such as glass, most plastics, paper and china, with little or no effect. Generally, these materials make excellent utensils for cooking in a microwave oven. Some other materials, such as metal and foil, tend to reflect microwave energy. Except for certain recommended procedures that involve the use of metal or foil as outlined in the use and care manual, use of metal utensils in microwave ovens should be avoided. If the cooking load is not large enough to absorb the microwave energy, the oven could be damaged by an arc between the metal utensils and the cavity interior or door assembly.