The microwave oven revolutionized the kitchen when it arrived as a new, must-have appliance. Unlike its predecessors, the microwave could cook food extraordinarily fast, lending a helping hand to weary cooks and people on the go.
Cooking with the radio
A microwave uses actual microwaves to heat food; microwaves are radio waves that are running at a frequency of about 2,500 megahertz. When radio waves travel at this frequency, they are absorbed by sugars, waters and fats-all found in food. This absorption converts the waves into something new: heat. Plastics, ceramics and glass do not absorb the waves at this frequency, allowing microwaves to use less energy and time because they heat only the food; other cooking appliances, such as the oven, heat the food and its container.
One of the prized attributes of a microwave is that it tends to heat items evenly if given the correct amount of time, so your food doesn't burn on the outside while you get the inside warm. Radio waves are able to penetrate food, cooking it evenly across its surface and throughout its interior. Conventional cooking methods, such as a convection oven, have to heat food from the exterior toward the interior as heat is absorbed into the item; this, along with the hot, dry surrounding air in an oven, can cause food to dry out, cook unevenly and even burn on the outside before the inside is fully cooked.
The inner workings of a microwave
Microwave ovens have two basic sections: a control section and a high-voltage section. The control section involves the timer, to control cooking time; protection devices, to prevent accidents; and a mechanism that limits power output. The high-voltage section is composed of a transformer, diode and capacitor arrangement to convert household electricity to significantly higher voltage, which is then converted into microwaves.