Everybody has heard one way or another that you shouldn’t put metal in the microwave. Whether it’s a foil-wrapped burrito or a fork in a bowl of pasta, metal in the microwave can lead to some heated consequences. So, what is the science behind the fireball in your kitchen? 

To understand the danger of putting metal in a microwave, it’s important to understand the basics of how a microwave functions. Microwaves are a type of radio wave which is created from a part inside of a microwave oven called a magnetron. (Don’t worry, it’s not a Decepticon) Through a complicated process of resonating electrons, a microwave is produced and sent into the cooking chamber of the microwave oven. In here, the microwaves reflect off the metal walls and absorb into the water molecules in your food. This causes the water molecules to vibrate and thus heat up, heating your food as well. This explains why foods with more water heat up quicker. With that being said, what makes it so dangerous to put metal into your microwave oven?  

So why can’t I put my baked potato that’s wrapped in foil into the microwave? The answer is quite simple. Microwaves themselves produce electric fields when they’re emitted. While microwaves will reflect off the thick metal inside of the cooking chamber, thin metals such as aluminum foil or utensils will absorb the electricity and heat up very quickly. In a matter of seconds, thin metals will begin to spark or even catch fire. Obviously, fire is not good for the integrity of the microwave. Aluminum foil is more dangerous because of its texture. If the foil is crumpled in any way, the texture causes small electrical arcs to be produced. These arcs get extremely hot and can cause sparks or even fire which can then lead to much larger damage.  So next time you are heating up some leftovers, make sure there isn’t any foil or utensils left on your plate or your mac and cheese will end up toastier than you might like