Some magnetrons have ceramic insulators with beryllium oxide (beryllia) added. The beryllium in such oxides is a serious chemical hazard if crushed then inhaled or ingested. In addition, beryllia is listed as a confirmed human carcinogen by the IARC;[citation needed] therefore, broken ceramic insulators or magnetrons should not be handled. This is a danger if the microwave oven becomes physically damaged, if the insulator cracks, or when the magnetron is opened and handled, yet not during normal usage.
It’s a good idea to clean your microwave regularly, even if you clean up spills or splatters here and there. To clean the inside, heat a microwave-safe bowl filled with water and a tablespoon of vinegar (white or apple cider will work) for several minutes. You want the inside to get steamy without the bowl of water to boiling over. Let the mixture cool for a few minutes before opening the door. Then, wipe the inside clean with a paper towel or use an abrasive sponge for any stuck-on food. Remove the turntable and either wash it by hand or in the dishwasher. Use an all-purpose cleaner for the exterior, but spray onto a paper towel or sponge first—not directly onto the microwave—to avoid it getting into the venting system. You should also avoid using bleach in your microwave.
For years, there wasn't much innovation in microwave technology — that is, up until Amazon introduced its own AmazonBasics microwave that works with Alexa. Now, you can use your voice to command your appliance to heat foods and the built-in tech will know exactly how long and at what power level to use. It's also the most affordable microwave you can buy.
Consumer ovens work around a nominal 2.45 gigahertz (GHz) — a wavelength of 12.2 centimetres (4.80 in) in the 2.4 GHz to 2.5 GHz ISM band— while large industrial/commercial ovens often use 915 megahertz (MHz) — 32.8 centimetres (12.9 in).[26] Water, fat, and other substances in the food absorb energy from the microwaves in a process called dielectric heating. Many molecules (such as those of water) are electric dipoles, meaning that they have a partial positive charge at one end and a partial negative charge at the other, and therefore rotate as they try to align themselves with the alternating electric field of the microwaves. Rotating molecules hit other molecules and put them into motion, thus dispersing energy. This energy, dispersed as molecular rotations, vibrations and/or translations in solids and liquids raises the temperature of the food, in a process similar to heat transfer by contact with a hotter body.[27] It is a common misconception that microwave ovens heat food by operating at a special resonance of water molecules in the food. As noted microwave ovens can operate at many frequencies.[28][29]

When shopping for a new countertop microwave, make sure to look for a microwave with adjustable heat settings: while most microwave tasks are performed on “high,” lower power levels are usually built-in to defrost frozen foods or tackle delicate tasks like softening butter or melting chocolate (one of our favorite uses: it’s quicker and less likely to scorch if you look away for a second).
If your microwave is broken, do not attempt to repair it yourself. Microwaves are dangerous to tamper with and should be serviced by professionals because the magnetron can retain a hazardous charge even when it isn’t plugged in. Most microwave manufacturers discourage people from even changing the light bulbs. But realistically, it’s probably cheaper and less of a hassle to buy a new microwave than to have it repaired.

For most people, microwaves are a must-have kitchen appliance for meal prep. Whether you want to popcorn or a warm bowl of soup, a microwave will get the job done in mere minutes. Plus, there's nothing to preheat, which helps you conserve energy in your home. Their convenience and ease of use are what make microwaves a staple for most modern households.
The 1.2-cubic-foot Toshiba didn’t heat as evenly as the smaller Toshiba. Unlike the 0.9-cubic-foot version, this Toshiba uses a steam and temperature sensor to automatically determine cooking time. However, we didn’t find the sensor particularly accurate: The baked potato we cooked using it came out completely raw in the center. In our heat map test, the marshmallows near the center of the turntable came out very dark. That said, it heated more evenly across the surface of the turntable than most of the microwaves we tested. The popcorn we made wasn’t burned, though it did have twice as many unpopped kernels as the 0.9-cubic-foot model. We liked that this model beeps to prompt you to flip meat while defrosting, something the smaller one doesn’t do. Impressively, this Toshiba only slightly cooked the edges of ground beef on the defrost mode, unlike most of the models we tested, which fully cooked entire sections of meat.

“What is microwave radiation? Is it dangerous? Are microwaves safe?” We see these questions a lot, so let’s clear it up once and for all: this type of electromagnetic radiation can be dangerous at high levels, but we’ve been using microwaves for decades, and it’s never been a problem. This is because, from the mesh door to the locking mechanism, microwaves are specifically sealed to prevent radiation from escaping, and the design works really, really well. However, if your oven door is damaged or if you think something is wrong, call a contractor and have them test radiation levels. It only takes a few seconds, and then you’ll know for sure.
From the late 1970s, Japanese companies such as Sharp Corporation manufactured low-cost microwave ovens that were affordable for residential use, leading to the rapid expansion of the microwave oven market in the 1980s. After Japanese dominance for much of the 1980s, with Sharp as market leader, South Korean manufacturers began entering the market in the late 1980s, with Samsung becoming a major microwave manufacturer.[18]

The effect of microwaving thin metal films can be seen clearly on a Compact Disc or DVD (particularly the factory pressed type). The microwaves induce electric currents in the metal film, which heats up, melting the plastic in the disc and leaving a visible pattern of concentric and radial scars. Similarly, porcelain with thin metal films can also be destroyed or damaged by microwaving. Aluminium foil is thick enough to be used in microwave ovens as a shield against heating parts of food items, if the foil is not badly warped. When wrinkled, aluminium foil is generally unsafe in microwaves, as manipulation of the foil causes sharp bends and gaps that invite sparking. The USDA recommends that aluminium foil used as a partial food shield in microwave cooking cover no more than one quarter of a food object, and be carefully smoothed to eliminate sparking hazards.[58]


^ Egert, Markus; Schnell, Sylvia; Lueders, Tillmann; Kaiser, Dominik; Cardinale, Massimiliano (19 July 2017). "Microbiome analysis and confocal microscopy of used kitchen sponges reveal massive colonization by Acinetobacter, Moraxella and Chryseobacterium species". Nature. 7 (1): 5791. Bibcode:2017NatSR...7.5791C. doi:10.1038/s41598-017-06055-9. PMC 5517580. PMID 28725026.
The invention of the cavity magnetron made possible the production of electromagnetic waves of a small enough wavelength (microwaves). The magnetron was originally a crucial component in the development of short wavelength radar during World War II.[6] In 1937–1940, a multi-cavity magnetron was built by the British physicist Sir John Turton Randall, FRSE, together with a team of British coworkers, for the British and American military radar installations in World War II.[7] A more high-powered microwave generator that worked at shorter wavelengths was needed, and in 1940, at the University of Birmingham in England, Randall and Harry Boot produced a working prototype.[8] They invented a valve that could produce pulses of microwave radio energy on a wavelength of 10 cm, an unprecedented discovery.[7]
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