How do microwaves work?
Microwaves have three properties:
In conventional cooking, the hotplate or oven has to heat up first, then the baking dish, before the heat can reach the food.
This is a long process which wastes a lot of energy. With microwaves, however, the heat reaches the food directly, with no detours on the way.
The microwaves penetrate the food directly and cause the water, fat or sugar molecules to vibrate. The friction caused by this produces heat, which then heats the food directly (like when we rub our hands together to warm them).
This property is called absorption, in other words the transfer of microwave energy to the water molecules.
Microwaves also have the property of passing through certain materials, in particular glass, porcelain, ceramic or even paper, without heating up the material itself. If the containers do get hot, it is because heat is transferred to them from the hot food.
However, microwaves are reflected off metal, so they bounce off the walls and the metal door screen, back onto the food.
This is why, for microwave cooking, no metal containers or plates with gold or silver decoration can be used.
