What Are Microwave Ovens?

microwave

In the kitchen, microwaves do everything from reheating leftover pizza to defrosting chicken breasts. But the best microwaves don’t just perform those tasks well—they elevate your cooking with features like sensor, grill and convection cooking. They also save energy with smart features such as power-saving modes and a programmable timer. And they’re easy to clean with interiors made of durable, scratch-resistant materials.

Microwave ovens use radio waves at a frequency of 2.45 GHz to heat food by dielectric heating, which is caused when the molecules in water absorb microwave radiation. The resulting energy causes water molecules to vibrate, which generates thermal energy. Microwave ovens were introduced to the public in the 1970s, following the development of less expensive cavity magnetrons.

Other uses for microwaves include point-to-point telecommunications and radar. Because of their higher frequencies, microwaves can travel more easily than lower-frequency radio waves. They can be focused into narrow beams, and antenna sizes are inversely proportional to the transmitted frequency. This means they can be sent over long distances without needing to bounce off the Earth’s surface or reflect off of the ionosphere, as is required for lower-frequency radio waves.

Other technologies that use microwaves include radar and the masers used to produce lasers (and blazes of light you’ve probably seen from friendly highway patrol vehicles and pocket laser pointers). Because the atmosphere absorbs microwaves above 100 GHz, they can only be observed by radio astronomers through high-altitude balloons or satellites.