Microwave is a form of non-ionizing radiation that’s used in many things including telecommunications, radar detectors, radio astronomy, curing wood, drying rubber and resins, and cooking food. Its wavelengths range from about one meter to one millimeter and its frequencies are between 300 MHz (0.3 GHz) and 300 GHz.
It’s made by a magnetron, a high-powered vacuum tube that generates microwaves by accelerating electrons in a magnetic field. The electrons whip around a circular path, like blowing on a straw, and are caught by two ring magnets above and below the anode of the filament.
Then they’re blasted into the cooking compartment of a microwave oven. The microwaves bounce off the reflective metal walls, just like light does.
When they reach the inside of your food, they make the water molecules inside it vibrate quickly. These fast vibrations heat up the water and cause it to cook the food.
Your food’s shape affects how fast it cooks in a microwave. Spherical foods cook faster than irregularly shaped ones.
It’s important to use a good quality microwave, which is not cheap! Some models have a “Keep Warm” function that keeps the food warm for up to 60 minutes.
Don’t put metal items in the microwave!
A metal item can easily catch fire in a microwave, because it’s not as easy to let the heat escape. That’s why it’s not a good idea to put anything like foil or tin foil in your microwave!