How do Microwave Ovens work to heat food?

Microwave ovens are a marvel of modern kitchen technology. Many of us can remember a time before microwave ovens when even heating the simplest leftover would require the oven to heat up and could take quite a while. Not only that, but such simple foods as a baked potato would take a great deal of time where today it will be done in a microwave in a matter of a few minutes. While many understand the basics of a traditional oven and how it works, they really don't necessarily understand what makes the microwave oven of today's kitchen work.

Microwave ovens use microwaves. A microwave is a type of electromagnetic radiation in a higher frequency range than radio waves. It actually is around the same frequency range that some wireless network devices and some portable phones use. This is the 2 gigahertz frequency range. Now, electromagnetic waves at this frequency can penetrate and affect waters, fat and sugars. When it does so, the atoms of these substance start to vibrate and become warmer and warmer as they continue to be exposed to the microwaves. Human tissue can be affected by radiation in this range of the electromagnetic spectrum. The eyes are especially sensitive to this frequency range. For this reason it is very important that you never operate a microwave that is damaged or the door or door latch is broken. It's also important not to stand against a microwave while it is in operation.

That much said, microwave ovens are a perfectly safe way to reheat food. The air inside a microwave does not naturally heat up and so there will be no browning or crisping of anything reheated within the oven. For this reason some microwave foods will come wrapped in a material that will heat and then in turn heat and brown or crisp the outside of the food that they package.

Since microwaves are emitted from one side of an oven, many such ovens will be designed with a rotating plate which is designed to help food cook thoroughly. It is possible that the microwaves may not penetrate through particularly thick foods and this movement helps to make more even distribution of the radiation as the plate turns.

The wavelength of microwaves is around 12 centimeters and for this reason, unless it is damaged the waves should not escape the cabinet of the microwave unless it is damaged or poorly designed. Microwave ovens have a magnetron inside them which is the source of the radiation that is used to cook our food. If you run a microwave without anything in it you will see sparks as the microwaves have nothing to be absorbed by and reflect and then collide with each other. The same is true if you use a substance that reflects the waves such as metal. Materials that do not absorb microwaves are considered microwave safe and include plastics, glass and ceramics.