1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

An Observation And A Question -- Why does metal arc in a microwave oven?

  1. May 26, 2015 #1
    So, I'm new around here and I'm not entirely sure if this is in the right section, but today I noticed something which I found thought-provoking. Before I go into this, I should point out that I'm 16, so all of my physics knowledge above high-school level is entirely self-taught, so I still have a lot to learn.

    Anyway, I'm on study leave from school, so my dad has been cooking me food to heat up in the microwave when I'm in on my own. He specifically said not to use a certain type of dish in the microwave, as they have a ring of metal around their rim. Now, I obviously know that you shouldn't put metal in a microwave, but being a physicist (and someone without that "don't do it voice" in their head), I decided to do it in the name of science. Now, I expected to see arcing around the metal rim, which I did. But that got me thinking- how can electrons be arcing on a continuous piece of metal. I mean, we see arcs of electricity when electrons jump form one piece of metal to another, but on a continuous loop, there is nowhere for them to jump between.

    Now, I presume that the high energy of the microwaves is causing electrons to arc from the air inside the microwave to the dish? If I'm wrong, please correct me. The reason I'm interested is that I plan on building a Farnsworth fusor this summer, only with deuterium added, and I am wondering about the high energies acting on this ring of metal. It gave me a few thoughts on circuits which could use this arcing effect, caused by the microwaves, in order to generate the high energies needed for deuterium fusion.

    If you have any thoughts on this, please let me know.
  2. jcsd
  3. May 26, 2015 #2


    User Avatar
    Gold Member

    I don't know the answer but it has been discussed here on this forum so I suggest a forum search, which actually is always a good idea if you have a fundamental question that you can be pretty sure someone else has had occasion to ask already.
  4. May 26, 2015 #3


    User Avatar
    Gold Member

    http://engineering.mit.edu/ask/why-can%E2%80%99t-we-put-metal-objects-microwave [Broken]

    Maybe here you can find the answer... there is ionization in the surrounding air...an that's why you get the lighting sparks.
    Last edited by a moderator: May 7, 2017
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook