What happens when you put metal in a microwave?

Answer 1

Running a microwave oven with metal in it will result in the reflection of the microwave energy off the metal. There is an exception, and that's the problem. Let's look at that.

If metal in a microwave is in a certain shape, that is, if it has a certain geometry, it can act as a microwave antenna. It can cause the microwave energy to generate "specific" electric currents in the metal, and voltages can spike high enough to create electric arcs in the cavity. That's bad. We can use metal in a microwave (like to cover the ends of drumsticks), but we must follow the manufacturer's instructions when doing so.

Answer 2

You get sparks or arcs in the microwave because the microwave radiation generates induction in the metal. It can also hurt the microwave because most likely would bounce around until they reflect the microwaves back to the oven's magnetron tube, which is the part that produces the microwaves. The magnetron will then probably be damaged.

Answer 3

Any metal or conductive object placed into the microwave will act as an antenna to some degree, resulting in an electric current. This causes the object to act as a heating element.

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