• Question: why cant you put metal in a microwave

    Asked by Kirito to Jos, Kate, Lisa on 20 Nov 2014.
    • Photo: Joshaniel Cooper

      Joshaniel Cooper answered on 20 Nov 2014:

      The microwaves are about the right frequency to be able to pull electrons out of metal things (which creates sparks and could break things). They do this because they are electromagnetic radiation and have a strong electric field which can pull out the electrons. If you see videos of metal in microwaves (on youtube or similar) you will see that the sparks come from the pointy-ist bits of the metal, where it is easiest to pull the electrons from.

    • Photo: Kate Dobson

      Kate Dobson answered on 20 Nov 2014:

      Like Jos said it’s about structure.
      Inorganic materials non-reactive, non-metal things like ceramic, plastic, or glass do not absorb the radio waves at the frequncy of the waves in your microwave and so don’t heat up very much. Organic materials (food) absord the radio waves at those frequencies and so heat up and cook. Metals reflect the microwave energy (the inside of every microwave is a metal box). If you put a completely flat sheet of metal in a microwave it should be safe, but getting the sheet completely flat, and making sure the corners and edges don’t cause problems is difficult so don’t try it at home!

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