Tasty Arrangements: How to Position Food in Microwave Cooking
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AbstractWhen you think of successful inventions from the 1900's that have dramatically changed how people live, what comes to mind? The car? Radio? TV? The computer? What about the microwave oven? You might not remember a time when microwave ovens were not a standard part of most kitchens, but your parents or grandparents probably do. They can remember when heating leftovers took a good 30 minutes in a traditional oven. Or thawing a food from the freezer meant leaving it in the refrigerator overnight. There was no warming of hot drinks, or 1-minute instant meals. The invention of microwave ovens changed all that.
Microwave ovens cook with radio waves, which, at a special frequency (around 2500 MHz), excite only the polar molecules in food, like water and carbohydrates, and not the food's plastic, glass, or ceramic container. This means that microwave radiation heats up only the food and not the food container or the air around it. However, the microwave-safe food container may also heat up, but that is because of the conduction of the heat from the food to the container, not the radiation. Microwaves also penetrate the food to a depth of about 2.5 cm, unlike traditional cooking methods, which heat the food by conduction, convection, or infrared radiation. This ability to heat only the food and to penetrate the food makes microwave cooking a faster and more energy-efficient form of cooking.
The limit on how far the microwaves can penetrate a food requires that you cut up an uncooked, raw food into similarly sized, small pieces to ensure that the food cooks evenly. Other things that encourage even cooking are keeping the food in a single layer (you shouldn't heap the small pieces into a mound). But what should you do if you have asymmetric raw pieces of foods, like broccoli or asparagus? Pieces that have one thick end, and one delicate, thin end? You could cut the pieces in half and cook the thick ends separate from the delicate ones, but what if you wanted to cook them altogether? Is there a way to cook asymmetric pieces of food in a microwave so that the pieces cook evenly without undercooking the thick ends, and without overcooking the delicate ends? (Read the Science Buddies science fair project idea Spinning Your Wheels: Pinwheel Sensitivity to see more examples of symmetry and asymmetry.)
In this cooking and food science fair project, you will try different arrangements of foods with asymmetric, raw vegetables to see which arrangement cooks the foods the most evenly. You will need to choose three raw test foods that can be cut into asymmetric pieces, such as broccoli, cauliflower, or asparagus. You will then need to prepare the pieces and arrange them in a 2-qt. microwave-safe container with a lid. In one trial, arrange the delicate tips so that they are in the center of the baking dish and the thick stem ends are lining the edge of the dish. In the other trial, arrange the pieces in the reverse order with the thick stems in the center and delicate tips near the edge of the baking dish. For each trial, cook the vegetables with the same amount of water (approximately ½ cup) and the same dish, for the same amount of cooking time. You will also need to allow 1-2 minutes of standing time. Seasoning, such as salt, should not be added to the vegetables while they are cooking.
To test and compare your vegetables after they've been cooked and have cooled, you will need to examine the delicate ends for any signs of being overdone; for example, you can count the number of brown spots. You will then need to measure the tenderness of the thick stem ends using your own test method, or using the one described in the Science Buddies science fair project, Tough Beans: Which Cooking Liquids Slow Softening the Most?, where small weights are used to cut through the thick stem with a cheese slicer. Once you've tested and compared your vegetables, you should know the secret of asymmetric food arrangement in microwave ovens!
This source describes how a microwave oven works:
- Brain, M. (2008). How Microwave Cooking Works. How Stuff Works, Inc. Retrieved October 5, 2008.
This source describes the history, principles, uses, and benefits of microwave ovens:
- Wikipedia Contributors. (2008, October 5). Microwave Oven. Wikipedia: The Free Encyclopedia. Retrieved October 6, 2008.
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