Pratica Chef Express Service Manual page 29

Microwaves are a type of radiant energy. As well as radio waves, visible light and infrared, the
microwaves are part of the electromagnetic spectrum, i.e., it is a form of electromagnetic radiation.
They are classified as non-ionizing radiation, because unlike x-rays and Alpha, Beta and Gamma rays,
its effects are strictly thermal and therefore do not after the molecular structure of the item that is
being irradiated.
The basic principle of microwaves is to cook by molecular vibration. They penetrate the food surface
in a depth that ranges from two to seven centimeters, heating the molecules of water, fat and sugar
by making them vibrate. The heat is transmitted to the interior of the food by thermal conduction,
demystifying the idea that the microwaves cook food from the inside out.
These are three characteristics of the microwaves which are important:
• Microwaves are reflected by the metals and can NOT pass through. The microwaves will
bounce back and forth until they find something to get attracted to.
• Microwaves can pass through most glass, paper and plastic with little resistance.
• Microwaves are attracted to sugar, fat, and water molecules in the food and will cause the
molecules to vibrate rapidly that converts into heat.
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