The Microwave Oven
British engineers and scientists are responsible for the technology which led to the microwave oven. John Randall and Harry Boot, working at the University of Birmingham, developed an improved high powered vacuum tube called a cavity magnetron for use in the development of small but powerful radar. It enabled radar sets to be much smaller than they were previously, carried in fighter aircraft among other uses. It served its purpose then, but the cavity magnetron is seldom used in radar applications today.
There are, nonetheless, well over one billion cavity magnetrons in use, and most of them are used several times a day. They are the source of the microwaves used in microwave ovens. The first microwave oven was developed by an American engineer, Percy Spencer, and his discovery was an accident. Spencer was working on a radar set in his capacity of an engineer for Raytheon when he found that it had melted a candy bar he had in his pocket. Spencer decided to experiment cooking food with radar, appropriately the first food he prepared with it was popcorn.
By 1947, Raytheon was marketing what it called the Radarange, a water cooled behemoth nearly six feet tall, weighing over seven hundred pounds. Suitable only for commercial use, Raytheon found a limited market. They licensed the technology to Tappan, who attempted to market a smaller version for the home. They too found market response to be less than enthusiastic. One problem with the early microwaves was that they were perceived by the public to be dangerous.
In 1967 Raytheon, through their subsidiary Amana, began to market a countertop microwave, using the Radarange name. Several other manufacturers marketed similar ovens, and the microwave became ubiquitous in American kitchens, break rooms, and wherever Americans ate. Whole new lines of food and packaging were developed to accommodate the ovens.
There has been a backlash against the use of microwave ovens by those concerned that they rob food of nutrients and flavor, cause unpleasant texture, and heat the food unevenly. Many people are unduly concerned over radiation leakage, despite it being highly unlikely. And by the way, the idea that a microwave oven cooks food from the inside out is incorrect, though they do heat to a greater initial depth than a radiant heat conventional oven.