Metal accidentally put in the microwave oven, such as tin foil or a fork, can act as antenna causing the microwaves to arc off them, forming dramatic and potentially damaging sparks or even a fire.

Microwaves cause water molecules in food to vibrate, producing heat that cooks the food.

Microwave ovens cook food with waves of oscillating electromagnetic energy that are similar to radio waves but move back and forth at a much faster rate. According to the US Food and Drug Administration, microwave energy is changed to heat as it is absorbed by food, and does not make food radioactive or contaminated.

Cooking in microwave ovens can affect the nutritional value of some foods, but this is no different from other cooking methods such as boiling, grilling, frying or even steaming. A microwave may actually do a better job of preserving the nutrient content of foods because the cooking times are shorter.