Japan's Sharp Corporation began manufacturing microwave ovens in 1961. Between 1964 and 1966, Sharp introduced the first microwave oven with a turntable, a feature that promotes convenient even heating of food.[16] In 1965, Raytheon acquired Amana. In 1967, they introduced the first popular home model, the countertop Radarange, at a price of US$495 ($4,000 in 2018 dollars).

Every microwave oven contains a magnetron, which generates microwaves. Those waves are then guided into the oven’s cavity, where they bounce around, rapidly swinging the polarity of charged molecules in foods (particularly water, fats, and sugars) and generating heat. Metal mesh on the door keeps those large-wavelength microwaves from escaping the metal box and cooking you. (This great video uses a disassembled model to explain further.)
Sir Henry Tizard travelled to the U.S. in late September 1940 to offer the magnetron in exchange for their financial and industrial help (see Tizard Mission).[7] An early 6 kW version, built in England by the General Electric Company Research Laboratories, Wembley, London, was given to the U.S. government in September 1940. The magnetron was later described by American historian James Phinney Baxter III as "[t]he most valuable cargo ever brought to our shores".[9] Contracts were awarded to Raytheon and other companies for mass production of the magnetron.
And let’s not forget about design! Today’s microwaves come in sleek, stainless steel frames that will look great in your kitchen and match your other appliances well. Microwave doors are easier to open, too. And if your current microwave is a little too small on the inside for your plates or cups, you can always upgrade to more cubic feet of space so you can use the dish of your choice! These microwaves cook your food better than ever.

Adoption has been slower in less-developed countries, as households with disposable income concentrate on more important household appliances like refrigerators and ovens. In India, for example, only about 5% of households owned a microwave in 2013, well behind refrigerators at 31% ownership.[24] However, microwave ovens are gaining popularity. In Russia, for example, the number of households with a microwave grew from almost 24% in 2002 to almost 40% in 2008.[25] Almost twice as many households in South Africa owned microwaves in 2008 (38.7%) as in 2002 (19.8%).[25] Microwave ownership in Vietnam was at 16% of households in 2008—versus 30% ownership of refrigerators; this rate was up significantly from 6.7% microwave ownership in 2002, with 14% ownership for refrigerators that year.[25]
And let’s not forget about design! Today’s microwaves come in sleek, stainless steel frames that will look great in your kitchen and match your other appliances well. Microwave doors are easier to open, too. And if your current microwave is a little too small on the inside for your plates or cups, you can always upgrade to more cubic feet of space so you can use the dish of your choice! These microwaves cook your food better than ever.
Like the 0.9-cubic-foot model, this Toshiba has one-touch start buttons from 1 to 6 minutes, a plus-30-seconds button, and a child-lock function. This model also shares several other features with the smaller Toshiba, such as a memory function and a multistage cooking function—but, realistically, we don’t think most people will use these controls often.
Any object containing pointed metal can create an electric arc (sparks) when microwaved. This includes cutlery, crumpled aluminium foil (though some foil used in microwaves is safe, see below), twist-ties containing metal wire, the metal wire carry-handles in paper Chinese take-out food containers, or almost any metal formed into a poorly conductive foil or thin wire, or into a pointed shape.[57] Forks are a good example: the tines of the fork respond to the electric field by producing high concentrations of electric charge at the tips. This has the effect of exceeding the dielectric breakdown of air, about 3 megavolts per meter (3×106 V/m). The air forms a conductive plasma, which is visible as a spark. The plasma and the tines may then form a conductive loop, which may be a more effective antenna, resulting in a longer lived spark. When dielectric breakdown occurs in air, some ozone and nitrogen oxides are formed, both of which are unhealthy in large quantities.
Spinach retains nearly all its folate when cooked in a microwave; in comparison, it loses about 77% when boiled, leaching out nutrients. Bacon cooked by microwave has significantly lower levels of carcinogenic nitrosamines than conventionally cooked bacon.[44] Steamed vegetables tend to maintain more nutrients when microwaved than when cooked on a stovetop.[44] Microwave blanching is 3–4 times more effective than boiled water blanching in the retaining of the water-soluble vitamins folic acid, thiamin and riboflavin, with the exception of ascorbic acid, of which 28.8% is lost (vs. 16% with boiled water blanching).[47]
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]
Every microwave oven contains a magnetron, which generates microwaves. Those waves are then guided into the oven’s cavity, where they bounce around, rapidly swinging the polarity of charged molecules in foods (particularly water, fats, and sugars) and generating heat. Metal mesh on the door keeps those large-wavelength microwaves from escaping the metal box and cooking you. (This great video uses a disassembled model to explain further.)
The Breville also makes it simple to customize based on the size, weight, and nature of the food you’re cooking. There’s even a reheat option for pizza. Alternatively, you can leave it up to the Breville’s sensor to detect moisture and temperature and accurately reheat. When we tried this in our testing of beverages and with our own lunches, it was surprisingly accurate.
Aside from the 10 power levels that this microwave offers, the most impressive feature of the Breville Quick Touch is the Sensor IQ function that automatically adjusts the cooking time for your food — meaning your microwave automatically measures the humidity that's being released from the food you’re reheating or heating, and calculates the cook time.
Uneven heating in microwaved food can be partly due to the uneven distribution of microwave energy inside the oven, and partly due to the different rates of energy absorption in different parts of the food. The first problem is reduced by a stirrer, a type of fan that reflects microwave energy to different parts of the oven as it rotates, or by a turntable or carousel that turns the food; turntables, however, may still leave spots, such as the center of the oven, which receive uneven energy distribution. The location of dead spots and hot spots in a microwave can be mapped out by placing a damp piece of thermal paper in the oven. When the water saturated paper is subjected to the microwave radiation it becomes hot enough to cause the dye to be released which will provide a visual representation of the microwaves. If multiple layers of paper are constructed in the oven with a sufficient distance between them a three-dimensional map can be created. Many store receipts are printed on thermal paper which allows this to be easily done at home.[40]
A microwave’s wattage tells you how much power it has, and more wattage means your food will cook faster and more evenly. You’ll typically see microwaves between 500 and 1,200 watts. Be aware that microwaves with fewer than 700 watts are generally underpowered and add time to the cooking process. These models are a good option for people limited by a budget, looking to save space, or willing to wait a few extra minutes. If you want a fully functional microwave to cook meat and vegetables, look for models with 1,000 watts or more.

Preprogrammed cooking functions use sensors and/or preset power levels and times to cook a variety of foods, including popcorn, potatoes, beverages, vegetables, and frozen meals. The sensors detect how much steam is emitted from the cooking food, but they aren’t always accurate. Franke said, “A lot depends on the skill of the person who’s programming it.” In our tests, the accuracy of these functions varied from model to model.


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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