Percy Spencer, an employee at Raytheon, accidentally discovered cooking food with microwaves, while building magnetrons for radar sets. The microwave oven contains a magnetron tube, which converts electricity into electromagnetic radiation or ‘microwaves’. These microwaves pass harmlessly through most objects, but get reflected by metals and absorbed by foods. Microwaves can penetrate the food by about 5 centimeters, and generate heat within the water molecules present in the food, thus cooking the food.
Microwaves ovens have universally become an indispensable tool of most kitchens today, and current estimates state that nearly 95% of American households own a microwave. Microwave cooking is made easier and more convenient with specially designed microwave cookware selections. Microwave cookware must be microwave transparent, that is, the electromagnetic radiation should be able to pass through them. To check if the cooking container is suitable for microwaving, place a jug full of water in the dish and microwave on full blast for one minute. The dish should remain cool when it comes out of the oven. If it’s hot, it is inappropriate for microwave cooking.
Specially designed microwave cookware like Tupperware is obviously good to use, and some ranges have some useful items. These include browning dishes, which are used to brown and crisp foods, and cooking racks, good for cooking meat, bacon and poultry, keeping it from sitting in its own fat during cooking. Most plastics work well in a microwave oven, but some plastics tend to melt when the food gets very hot. This is a problem when cooking foods with a high fat or sugar content, and these should only be prepared in cast-iron or stainless steel pots.
Microwave oven cookware is generally made from glass, ceramic or special plastics; however not all glass, ceramic and plastic containers are microwave safe. Safe microwave cookware typically includes heat-resistant glassware, chinaware, firm plastics and polythene like Tupperware. Hazardous materials or utensils unsafe for microwaving are crystal or cut glass, unglazed earthenware and pottery, soft polythene, stainless steel or metal, foil, margarine tubs, whipped topping bowls, cheese containers, dishes with silver and gold trim.