Learn about the stories behind 10 extraordinary inventions. In this video, you'll learn about microwave cooking.
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Male Speaker: Microwaves are radiowave not unlike those that you hear music from stations to our homes and cars. They oscillate at a frequency of 2450 megahertz or 2.45 billion times a second. When you press cook, microwave -- the metal interior walls of the oven although the waves will bend off metals they pass through most substances such as a plastic dish virtually unnoticed. They are however absorbed by the water, fat, sugar and salt in foods. The energy contained in the waves is converted into atomic motion. This intense friction between molecules produces heat making them ideal for use in cooking. Microwave ovens are also extremely electrically efficient. In that they only heat up the food, not the air surrounding it. This property does have a slight drawback in that microwave oven's -- to form. Unlike conventional ovens which rely on conduction to transfer heat to the center of food, microwaves penetrate fairly evenly in a matter of seconds or minutes depending on the thickness of the food.