Microwaves pass through most glass, paper, and plastics without heating them so food absorbs the energy. Microwaves bounce off metal pans so food does not absorb the energy.
Microwaves may not reach the center of a roast. The heat spreads to the center from the outer, cooked areas just as in regular oven cooking. This is one of the reasons for letting some foods (for example, roasts or baked potatoes) stand for a while after cooking, or for stirring some foods during the cooking time.
The microwaves disturb water molecules in the food. As the molecules bounce around bumping into each other, heat is made, like rubbing your hands together. This is the heat that does the cooking.
Radio interference
Operation of the microwave oven may cause interference to your radio, TV, or similar equipment. When there is interference, it may be reduced or eliminated by taking the following measures:
l Clean door and sealing surfaces of the oven.
l Adjust the receiving antenna of radio or television.
l Move the receiver away from the micro- wave oven.
l Plug the microwave oven into a different outlet so that the microwave oven and receiver are on different branch circuits.