Sue Snider: Hello, I am Sue Snider with the University of Delaware, department of Animal and Food Sciences. We are going to be talking about preparing foods in the microwave and today, I want to talk about how microwaves cook foods. Microwaves are fast, they are convenient and one of the real benefits is that its a snap to clean up. Microwaves are electrical and magnetic waves. They are produced by a magnetron in your microwave oven and they possess some unique characteristics that make microwave food preparation interesting. One of the first characteristics of microwaves is that it is reflected away from metals so that the electric, magnetic energy comes in, hits the metal and is reflected away. This is the reason why metal containers or even dishes that have metal cannot be used in the microwave. The sides of the microwave, the bottom of the microwave is made from metal. Its designed to actually to do that to reflect the microwaves. Another unique characteristic of microwaves is that they pass through certain materials like glass, paper, plastic; these are the things that we use to cook the microwave foods in. Later, we will be talking about choosing our safe products to the cook the microwave foods. Finally, microwaves are unique in that when they hit the food, they are absorbed and when they are absorbed, they excite polar molecules primarily water and causing them to vibrate. This vibration produces heat much like if you take your hands, put them together, rub them back and forth very quick, you will feel the heat build up. This is the same thing thats happening when foods absorb microwaves. Now, one of the myth associated with microwave cooking is that the food cooks from the inside out. Microwaves penetrate about one inch into the food, so that any food that is thicker than that, the remaining heating occurs by conduction which is where one particle is heated, that heat is transferred to the next, to the next, to the next. This is the same kind of heating that occurs in your conventional oven, so the food does not heat from the inside out, it may appear that way since thin foods appear to cook very, very quickly all the way through at one time. We have talked about how microwaves work, some of the unique characteristics of microwaves. In the next segment, we will talk about choosing microwave ovens and looking at the wattage of microwave ovens.