{"id":2108,"date":"2010-08-31T08:00:44","date_gmt":"2010-08-31T15:00:44","guid":{"rendered":"http:\/\/www.todayifoundout.com\/?p=2108"},"modified":"2013-08-02T19:41:33","modified_gmt":"2013-08-03T02:41:33","slug":"why-you-generally-shouldnt-put-metals-in-the-microwave","status":"publish","type":"post","link":"http:\/\/www.todayifoundout.com\/index.php\/2010\/08\/why-you-generally-shouldnt-put-metals-in-the-microwave\/","title":{"rendered":"Why You Generally Shouldn\u2019t Put Metals in the Microwave"},"content":{"rendered":"

\"Microwave\"<\/a>Today I found out<\/a> why you generally shouldn’t put metals in a microwave.<\/p>\n

First, it should be noted that it is not unsafe to put all metals in the microwave. \u00a0Indeed, you often put metals in the microwave anytime you put a hot pocket in the little pouch and place it in the microwave. \u00a0The pouch has a thin layer of aluminum lining the inside that is designed to absorb the microwaves and heat up a bit so as to brown the outside of the hot pocket.<\/p>\n

On top of that, the inside walls of your microwave oven are made of metal. \u00a0 This forms something called a Faraday Cage which traps the microwaves inside the box, so that they cook the food and not things around the microwave oven, like you. \u00a0If you look closely, you’ll also see that the window you look at the food through has metal mesh lining it. \u00a0The holes in this mesh are smaller than the wavelengths of the electromagnetic radiation your microwave is producing. \u00a0This makes it so the waves can’t pass through the holes. \u00a0Visible light, however, is\u00a0comprised\u00a0of much smaller wavelengths, so that form of radiated energy passed through the holes just fine, allowing you to see inside your microwave while it’s running without getting cooked yourself.<\/p>\n

So if the inside of your microwave is lined with metal and certain food products, such as hot pockets and pot-pies, have containers that contain metal, why does your microwave manual say not to put metal in the microwave?<\/p>\n

\"how<\/a>First, let’s talk a little about how a microwave oven actually works. \u00a0At its core, a microwave oven is a pretty simple device. \u00a0It’s basically just a magnetron hooked up to a high voltage source. \u00a0This magnetron directs microwaves into a metal box. \u00a0These generated microwaves then bounce around inside the microwave until they are absorbed via dielectric loss in various molecules resulting in the molecules heating up (more on how this works in the Bonus<\/span> Factoids<\/a> <\/em>section). \u00a0Matter that work well here are things such as water, ceramics, certain polymers, etc. \u00a0These all end up converting microwave energy into heat quite\u00a0effectively.<\/p>\n

Metals, on the other hand, are great conductors of electricity, being packed with electrons that can move freely. \u00a0Depending on the shape\/type\/thickness\/distribution\/etc. of metal, you may observe some heating of the metal itself in the microwave or none at all. \u00a0You may also observe some arcing of electricity or none at all. \u00a0In any event, when these microwaves hit the metal, free electrons on the surface of the metal end up moving from side to side very rapidly. \u00a0This, in turn, prevents the\u00a0electric\u00a0wave from entering the metal; thus, the waves end up being reflected instead. \u00a0However, there is also the potential that this ends up creating a sufficient charge density that the electrical potential in the metal object exceeds the dielectric breakdown of air. \u00a0When this happens, it will result in arcing inside your microwave, from that metal to another electrical conductor with lower potential (often the wall of the microwave). \u00a0In extreme cases, these electrical sparks can end up damaging the wall by burning small holes in the metal wall. \u00a0It can also end up burning out the magnetron in your microwave oven or, in modern microwaves, can provide a surge that ends up damaging sensitive microelectronics, possibly killing your microwave or making it unsafe to use, in the case of a hole in the inner metal wall in your microwave.<\/p>\n

Another way it can kill the magnetron of your microwave is when enough of the generated microwaves don’t get absorbed, such as if the food is wrapped in aluminum foil or mostly enclosed in a metal container. \u00a0This can create a lot of energy not getting absorbed, with nowhere to go but eventually back to the magnetron, which can eventually damage the magnetron. \u00a0Once again, killing your microwave oven.<\/p>\n

On a more mundane level, something like a spoon or a metal plate or the like, positioned correctly, will simply make your food potentially not cook normally. \u00a0On that note, it is once again, actually acceptable to put metal in a microwave under the proper conditions. \u00a0Some microwaves even have metal grates inside for setting food on, such as is often the case with certain convection ovens. \u00a0There are also certain types of metal pots and pans that are microwave safe. \u00a0These all, however, are carefully designed to not cause any problems in your microwave oven. \u00a0In general, putting metal in the microwave is unsafe, not because you are at risk of bodily harm or the like (though in extreme cases a fire might be started in your microwave), but, more to the point, primarily because it has the potential of damaging your microwave in the ways listed above.<\/p>\n

If you liked this article, you might also enjoy our new popular podcast, The BrainFood Show (iTunes<\/a>, Spotify<\/a>, Google Play Music<\/a>, Feed<\/a>), as well as:<\/p>\n