字幕表 動画を再生する 英語字幕をプリント How do microwaves cook your food? If you stand in front of a microwave are you going to get cancer? Are they killing you?! Howdy cookers, thanks for watching DNews, I'm Trace. This morning, I was talking to our intern Tori // hello! // about how I microwaved coffee from yesterday. Yeah, I know, it's gross. But it's SO EASY! Microwaves are magic food boxes. They heat food in less time with less energy than traditional methods -- but HOW they make that thing hotter is a mystery to many of it's users... The microwave has roots in radar research during World War II. Scientist Percy Spencer accidentally melted a candybar in his pocket and after some more experimentation, he patented[a] the first microwave heating device! Microwaves are basically metal boxes containing a magnetron gun. The magnetron uses electricity to excite electrons and get them to vibrate and release waves of non-ionized electromagnetic energy. This radiation is at a frequency that's between radio waves and infrared light -- usually around 2.45 gigahertz. This microwave "radiation" is no different from the radiation created by a radio station or a wifi-network. The literal microwaves are made of alternating current, and magnetic fields. Because it's Alternating it means they're switching from clockwise to counterclockwise back and forth. These electromagnetic waves shoot from the magnetron into the oven passing through paper, plastic, and glass to hit the water, fat and sugar molecules in your cup of coffee or frozen burrito. Scientists aren't EXACTLY sure what happens at this point. Either the waves cause the H2O molecules to agitate and generate heat, OR the fats, sugars and water absorb the energy and release heat. Either way, when the magnetron energy hits, heat is created, and a minute or so later, yesterday's coffee is as good as… well yesterday's coffee. Only hotter. Because it's just heating water, fat and sugar -- if it's not evenly distributed throughout the burrito, it won't heat well! Cold patch, yuck... Also, setting it too hot too fast will only mess up the process because the heat has to travel into the food by conduction, that is, one molecule spreads heat to the next and then the next. What a pain in the butt. My mom used to tell me, "If you want children someday don't stand too close to the microwave!" Which isn't really true. This microwave radiation isn't nearly as strong an an x-ray, or as common as wifi, cell phone, televisions or other electromagnetic waves flying around. Studies have found low-level microwave exposure shouldn't cause the corruption of DNA that results in cancer. And looking into the microwave is fine, the windows are shielded so microwaves are reflecting onto the food, not into your sensitive little eyeballs. Metal in the microwave, isn't inherently bad, either. After all, the walls are made of it because it reflects the waves all around, heating as much of the food as possible. However, throwing in something POINTY, like aluminum foil, can cause sparks, and breakdown of air molecules into more dangerous fumes. The sleeves that come with some pastries are also for reflection, because as the outside of the food heats up, that heat energy is reflected BACK at the crust, crisping it up. It's cooking itself! Whether microwaving is damaging the food is still being debated by science, but for the most part ANY cooking damages the nutrient content of the "raw" food, but cooking it also kills bacteria which makes food safer. Yes, a few older studies found breast milk, heated in a microwave, lost some of it's vitamin B12 potency. But many other studies have found no such evidence. And MANY studies done on microwaves have determined there's little or no difference between microwaving and conventional cooking. Ultimately, the most dangerous things microwaves produce are food burns from overheating the item. And that's just your fault. The FDA says microwaving food is just as safe and nutritious as any other method of cooking. But what do you think? Are you nervous about them? Do you microwave your food? Speak your mind down in the comments and be sure you subscribe for more DNews. Microwaves are also produced in space, and on Wednesday, August 27 we're doing our next monthly SpaceOut with NASA/JPL! This month we're talking about Europa, the possibility of life and future missions to Jupiter's intriguing moon! RSVP with the link here or in the description and post a question so we can ask the experts! Thanks for watching DNews.