Microwave Facts

History

• Percy Spencer, an engineer, worked for a company as a radar researcher in 1945. Spencer approached a magnetron, a high-frequency radio wave transmitting tube, and noticed that the chocolate bar in his pocket melted. With this new knowledge of using radio waves to cook food quickly, Spencer and some colleagues set to work on creating the first microwave oven. These ovens were large and ill-equipped for home use, especially paired with enormous price tags. The models eventually became smaller until the first compact microwave oven was designed in 1967.

How Microwaves Heat

• The smaller magnetron within the microwave oven uses electricity from a home circuit to create radio waves. These waves transmit at a 2450 Megahertz frequency, which creates vibrations and high temperatures that then cook the food. Despite the conception that microwaves cook from the inside out, these appliances actually heat from the outside in. According to the USDA Food Safety and Inspection service, microwaves penetrate food at a depth of 1 to 1 1/2 inches. Microwaves come in a variety of power levels, such as 800 or 1100 watts. These numbers reflect the amount of power the microwave uses to cook food; higher wattage microwaves take less time to heat food.

What Not to Microwave

• Items such as heatproof glass, some plastics and paper plates can all be used in a microwave safely, but many products should not be microwaved, just as many food items should not be used in a microwave. Any metal surface, such as silver utensils or aluminum foil, should not go in the microwave as this creates a fire hazard and can break the microwave. Foam cups or plates should also not be used within microwaves. Trying to cook things like whole turkeys or cakes and pies within the microwave should be avoided. Because microwaves only reach up to 1 1/2 inch into food, thicker foods like turkeys will not be cooked completely through.

Microwaves and Safety

• Because of the shallow penetration of radio waves to food in microwaves, food oftentimes may not be cooked completely through, with thinner parts of food heating and thicker parts remaining cold. The USDA notes that a thermometer helps ensure food safety by checking the thicker area of a meal for proper temperatures. Burn potential also crops up with regards to food safety in the microwave. Food should rest for a few minutes after cooking ends to avoid this. The major concern with microwave usage is the potential to cause cancer. However, experts say that cooking foods in microwave ovens has not been determined to cause cancer, according to the Alabama Cooperative Extension System.