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Why Can't You Put Metal in the Microwave?

Why Metal's So Damaging to Your Microwave

Even the most cooking challenged would agree: you'd be hard-pressed to mess up popcorn, a TV dinner, or soup in the microwave. But stick a sheet of foil in on accident, and it's a recipe for disaster — just ask my 8-year-old self! So why does the microwave take poorly to metal?

Microwave oven transmitters produce electromagnetic radiation ("microwaves") that disturbs electrons (the negatively-charged bits inside atoms), creating kinetic energy and thereby producing heat. That's how materials that receive radiation, like food and water molecules, become heated. The game changes with certain metals, however, which can be so dense that molecules, when agitated, have nowhere to go. The electrically conductive metals bounce off microwaves, rapidly creating a high voltage between the metal and the radiation source. Once the voltage strength surpasses a certain threshold, a spark is produced and can lead to a fire.

Have you ever unknowingly put metal in your microwave? If so, tell us what happened.

Image Source: Thinkstock
Join The Conversation
Susannah-Chen Susannah-Chen 5 years
"That little foil leaf quickly became a rather large candle within seconds." — Ha! :cake: :innocent:
fuzzles fuzzles 5 years
No fair, Susannah! No clean-up? I didn't even get to eat the forking cupcake! *kicks desk* I'll trade your twister for one..almost...in perfect condition...foil leaf! *eyes darting* ;)
Susannah-Chen Susannah-Chen 5 years
This happened to me when I was a kid. I accidentally left the metal twist in something and all of a sudden sparks started flying, and the double-walled glass door shattered within seconds! It was pretty cool, actually, to see a million pieces of glass shatter to sand but not have to clean it up.
fuzzles fuzzles 5 years
Yes, I have caused a premature death of a microwave! I was about 6 years old when I decided to nuke a leftover cupcake from the wedding of a cousin. While the wrapper was paper, it sported a decorative foil leaf. WOOOSH! That little foil leaf quickly became a rather large candle within seconds. If memory serves me, I was grounded for about two weeks and it took me years to earn the right to use the replacement 'wave without adult supervision.
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