Welcome to brain Stuff production of iHeart Radio. Hey brain Stuff. Lauren bog Obam here with another classic episode from our archives and our previous host, Christian Sager. Today's topic is about one of those modern miracles of the kitchen and heroes of quick cooking and leftovers alike, the microwave. Hey, brain Stuff. This is Christian Sager. There is no denying it. Microwave ovens are super convenient. They can heat food much more quickly than a conventional oven, although not always with
the same results. And there's an entire industry of food made specifically for these nifty gadgets. But how do they work? Yeah, of course you're saying right now, well microwaves. Sure, yeah, microwaves. But what the heck are microwaves? Good question, Christian. Microwaves are a type of wave on the electro magnetic spectrum,
and their sandwiched between radio waves and infrared adiation. In the case of microwave ovens, the most common wave frequency is roughly two thousand, four hundred and fifty mega hurts that's about two point four five giga hurts. Waves in this frequency range have an interesting property. They're absorbed by water, fats and sugars, and once absorbed, they're converted directly into atomic motion, which we like to use as heat. These
waves have another convenient property. They're not absorbed by most plastics, glass, or ceramics. Metal, however, does reflect microwaves, which is why it's a bad idea to leave a spoon in your cheese dip when the ovens on. It's also why the devices have metal walls for reflection. You'll often hear people say microwave ovens cook from the inside out, right, that's the key to the speed. Think about it like this. Let's say you're baking a cake in a conventional oven.
Normally you would bake it at three and fifty degrees fahrenheit or a hundred and seventy seven degrees celsius. But this time you accidentally set the oven at six hundred degrees fahrenheit. The outside of the cake will burn before the inside even gets warm, and you'll have ruined somebody's birthday. In a conventional oven, the heat has to migrate by conduction from the outside of the food toward the middle.
Hot dry air on the outside evaporates moisture, so the outside can be crispy and brown like the crust unbread while the inside is moist. In microwave cooking, the radio waves penetrate the food and excite water and fat molecules more or less evenly throughout. No heat has to migrate toward the interior by conduction. There's heat everywhere, all at once because the molecules are all excited together. There are limits to this, though. Microwaves penetrate unevenly in thick pieces
of food. They don't make it all the way to the middle, and there are also hot spots that are caused by wave interfere It's but you get the idea. The heating process is different because you are exciting atoms rather than conducting heat. Inside a microwave oven, the air is at room temperature, so there's no way to form a crust. That's why microwavable pastries or hot pockets sometimes come with a little sleeve made out of foil and cardboard.
The sleeve reacts to microwave energy by becoming very hot. This exterior heat lets the crust become crispy, as it would in a conventional oven. Today's episode was written by Ben Bolan and produced by Tyler Klang. Brain Stuff is production of I Heart Radio's how Stuff Works. For more in this and lots of other quick topics, visit our home planet how stuff Works dot com and for more podcasts.
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