Microwaves are fast and energy efficient because they only heat the food, not the space around it. Microwave ovens cook using microwaves of the 2500 MHz range. Water, fats and sugars absorb the radio waves and the excited molecules then emit heat. Microwaves are not absorbed by most glass, ceramics or plastics and are reflected by metal. That's why your cookware remains cool after microwaving, and why, if you've ever put metal in your microwave, you've seen sparks fly.
Microwaves tend to heat food evenly.
Because radio waves penetrate everywhere at once, there is no crust formed to seal in flavors. That means bread goes soggy, meat turns leathery, cookies look unbaked. Microwaves are great for reheating, boiling water, boiling vegetables, and if you make follow special recipes they can cook meals too, but not many people make the effort. Convection Ovens Convection ovens have been in use for quite a while, but remain more common in the commercial cooking industry than in the home. Convection works by having a fan in the oven circulate air evenly and uniformly around and onto the food.