Why Are Microwaves Made of Steel?

Types of Microwaves

• Microwave ovens are available in a variety of forms, however they all operate in the same manner. The most common microwaves are countertop and above-the-range models. Above-the-range models are popular because they double as a hood vent, which is a requirement of most building codes, while countertop models are a convenient addition to any kitchen lacking a microwave.

How Microwaves Work

• Microwaves heat your food by heating the water particles contained inside. The microwave's magnetron creates sharp radio waves, called microwaves, that are then distributed into the oven from the top. The microwave has a stirrer at the top, that functions like a fan, spreading the waves throughout the cavity. The waves bounce off of the interior walls, passing through the food. The waves create a magnetic field that agitates the water molecules as they pass. The water molecules begin to move back and forth rapidly -- approximately 2.5 billion times per second. This movement creates friction, which causes heat.

Why Steel?

• The interior walls of the microwave are constructed of steel because of the steel's ability to reflect the microwaves. However, not all steel is created equal, and some steel, such as many varieties of cold-rolled steel, absorb rather than reflect the microwaves. In many microwaves, stainless steel is used, as it is an inexpensive material known to reflect microwaves.

Health Concerns

• Preparing food using the microwave is a quick means of heating up leftovers or cooking a complete meal, however, research suggests that it is not the healthiest means of food preparation. The "Journal of the Science of Food and Agriculture" published a study in which it found broccoli lost 97 percent of its nutritional value when microwaved, compared to the 11 percemt lost when the broccoli was steamed.