5
How the microwave oven works
In the microwave oven there is a high voltage valve
called "Magnetron" that converts electric energy to
microwave energy. These electromagnetic waves
are conducted to the inside of the oven cavity by
means of wave-guide and spread by a mode stirrer
or by a turntable.
Inside the oven the microwaves spread out in all
directions and are reflected by the metallic walls,
penetrating the food evenly.
Why does the food heat up?
Most food contains water, whose molecules vibrate
with microwaves.
The friction between the molecules generates heat,
which causes a temperature rise in the food,
defrosting it, cooking it or keeping it warm.
As the heat is formed inside the food:
-
It may be cooked with little or no liquid or fat;
-
Defrosting, heating or cooking in the microwave
oven is quicker than in a conventional oven;
-
Vitamins, minerals and nutritive substances are
preserved;
-
There is no change in the natural food colour
and aroma.
The microwaves travel through porcelain, glass,
cardboard or plastic but not through metal.
Therefore, recipients made of or containing metal
should not be used in the microwave oven.
The microwaves are reflected by the metal
They travel through glass, porcelain…
They are absorbed by the food.
