what are some causes of microwave heat?
958774
the microwave literally shoots microwaves at the food; these microwaves then vibrate the food particles, causing friction, which heats them up.\n\nhttp://www.gallawa.com/microtech/how_work.html how a microwave works, technically
164160
One of the basic characteristics of microwave energy is that it is reflected by metal. The extent to which microwaves are reflected varies with the type of metal. For example, aluminum and stainless steel reflect microwaves, while certain compositions of cold-rolled steel will absorb microwave energy to some extent. However, for all practical purposes, it may be said that metal reflects microwave energy.\nThe characteristics of microwaves make it possible to contain them within a specially constructed metal enclosure called a cavity . The microwaves bounce around this  oven cavity until they are either absorbed by food or dissipate into the air. The interior metal walls of a microwave oven cooking cavity are proportioned with the energy output from the magnetron tube. In other words, the physical proportions of the cavity are tuned to the frequency of the energy, thus producing a uniform electromagnetic wave pattern. (The sealing properties of the door, which essentially appear as a metal wall to the microwaves, and the resonant characteristics of the oven cavity, will be considered in more depth in future additions). Therefore, under normal circumstances the energy reflects from wall to wall like beams of light in a mirrored room. However, if something were to disrupt that energy pattern, it would produce undesirable results, such as arcing.\nLike a Small Bolt of Lightning\nWhen metallic objects are indiscriminately placed in a microwave oven cooking cavity, the energy pattern becomes disrupted and distorted. This condition produces arcing. When two metal objects, such as a metal bowl and the [metal] cavity wall, are placed in close proximity and subjected to an intense field of microwave energy, arcing will result. Arcing in a microwave oven is like a small bolt of lightning Arcing occurs because the air between the two metallic objects becomes electrically charged, just as the air between a thundercloud and the earth becomes charged or ionized. This ionized air becomes an electrical conductor, and electric current then leaps the gap like a small bolt of lightning.
254442
Microwave Ovens are set to the wave lenght of water particles (also some metals and grease particles have the same oscillation coefficient). So they are absorbed by the water and grease. It depends which part f the food has more moisture. But if the outside has enough water, it will heat from there to the middle. Try putting a piece of cheese ad see how the outside melts first.
722141
Microwave is any electromagnetic wave with "frequencies between 300 MHz (3 x 108 Hz) and 300 GHz (3 x 1011 Hz)."(1)\n\nThe most common impact could be seen in Microwave Ovens where food is heated up by causing the molecules in it to vibrate so fast, it heats up.\n\nIt is also used in radio broadcasting, radars & Wireless LAN protocols (e.g. Bluetooth). GSM mobile networks & cable TV use microwave.\n\nMicrowaves are used in maser, a device similar to laser, just that it operates at microwave frequencies.\n\nMore at: http://en.wikipedia.org/wiki/Microwaves
20070
Cooking food with microwaves was discovered by Percy Spencer while building magnetrons for radar sets at Raytheon. He was working on an active radar set when he noticed a strange sensation, and saw that a chocolate bar he had in his pocket had melted.\n\nIt was patented in 1946
917582
Not very well. Biscuits need time to rise while they cook. With a microwave you just get hot biscuit dough.
877766
The microwaves hae a frequency which is very close to the distance between the Hydrogen and Oxygen atoms in the water molecule. Because of this fact it causes that bond to vibrate and thereby adding energy or heat. This is why water is required for a microwave.
953528
Okay maybe I shouldn't be answering this question. For one I've never even heard or read about that. However I do know from first hand experience...that a cell phone will cause a microwave to arc. I was cooking something, and a cell phone was about six inches from the microwave. As soon as I started the microwave it arced. Moved the cell phone, and the microwave worked just fine. Cell phones are a strange thing.
858685
A microwave excites water thermally and unevenly at that.  A modern microwave in good repair poses no risk to you regarding microwave radiation.  The Faraday's cage (a metal net surrounding the microwave) protects you completely from radiation.\n\nIt is true, though, that water can be heated to an unusual gas-liquid stage if only a small amount of water is heated for half-an-hour or more, which is very unstable when released to an open atmosphere.  Hot water can explode when sufficient supercritical water (much above the temperature for evaporating) meets a quick change in water vapor pressure (lots of steam leaves the surface of the supercitical water).\n\nIn conclusion, under normal circumstances there is no risk to your health whatsoever.  If you microwave materials to really, really, really high temperatures, it is reasonable to expect trouble.  If you open the microwave door and notice an incredible amount of steam escaping, close the door most of the way and leave the area completely.\n\nThe mostly closed door with facilitate or slower and thus more stable transition to room conditions.  Always exercise caution with scalding hot materials, but the microwave has a way of heating things past the temperature that you are planning or expecting.  As the heat dissipates, so does the hazard, no different than with any other machine.
495856
not that i know of, in fact my microwave puts additional flavor in my food, but i haven't cleaned it ever nor have i put a lid on anything, and i don't use a plate, i put my lasagna on the rotating tray, then remove it with my paws, then i cook macaroni in the microwave, i put the noodles and water and cheese powder and milk on the rotating tray, then i pour my cereal on it too, just fo kicks, all my friends love it, only kidding, i can't believe you fell for that, i don't really have friends, wahhhhh!!!
679767
Microwave ovens use microwaves (obviously) specifically designed to be absorbed only by the food. However, when the food gets hot, heat is then transfered to the dish. Technically, the microwave only (directly) heats the food.\nIn contrast, all a convectional oven does is heat everything inside, regardless of what it is. In this case, the dish usually heats up more quickly because it has a lower specific heat, depending on what food is in the dish.
1886
If you're talking about microwave ovens, the microwave heats up the water molecules in an egg, creating steam which builds up enough pressure to cause it to explode.
515562
Friction, Heat generated to name 2 reasons.
242893
Hmm, I'm sitting here thinking about how microwaves work (yes, I do know how). If the pills have moisture in them (which I'm sure they do), then the electons in the pills can get energized by the microwaves and change the substance of the pills completely. The heat from the outside of the microwave itself though can alter the chemicals in the pills. It might be unlikely that anything happened to yours, but I'd just be on the safe side about it.
484702
Why is this on a BIOLOGY quiz? It's a physics question.\n\nAnyway, the short answer is that microwaves are absorbed preferentilaly by certain materials, most commonly by water. Because most foods conatin water they can absorb the microwaves. The microwaves excite the water molecules producing heat and cooking the food.
430085
They don't?? how long did you try? Ibelieve they should die, maybe as they are small they absorb too little microwaves.. but if you keep on microwaving they will burn.\nLet us know!!!
758527
Microwaves are part of the electromagnetic spectrum. As such any hot body will emit them. The peak frequency of the emissions of a body go up as it gets hotter. For your body the peak is in the infrared. For hot coals, it is in the red. Microwaves correspond to a temperature of a few Kelvin - about -260 C. Of course, at this temperature not much of any kind of radiation is given off, but what there is will peak in the microwave.\n\nFor commercial production of large amounts of microwaves- for ovens or radar - a magnetron is used.