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About this Article
Written by: Jaime Clevenger
Written on: November 1st, 2000
Tags: food & drink
Thumbnail by: Christian Rasmussen/Wikimedia Commons
About the Author
In Fall 2000, the author was a student at USC.
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Volume II Issue III > The Engineering Behind the Microwave Oven
The microwave oven recently celebrated its golden anniversary. As familiar an appliance as it is to many people, few really know how it works. This article will provide some insight into the history of the microwave oven's discovery and development, as well as elaborate on the internal workings and mechanisms that provide the "magic" behind the function of this seemingly mysterious box.

History

In today's technology-driven world, almost everyone, at some point in their lives, has either used or had some sort of contact with a microwave oven (see Fig. 1). Today, these familiar kitchen appliances have found a niche for themselves in as many as ninety-percent of American homes [1]. However, popular opinion was not always so overwhelmingly supportive of this breakthrough technology, as the microwave oven initially struggled to gain acceptance since its inception over fifty years ago.
Like many of the great inventions of our past, the idea behind the microwave oven was accidentally stumbled upon in 1946. Dr. Percy Spencer was working as an engineer with the Raytheon Corporation at the time, when he discovered something very unusual one day while working on a radar-related research project. While testing a new vacuum tube known as a magnetron, he discovered that a candy bar in his pocket had melted. Intrigued as he was, Spencer decided upon further experimentation. Later on, having pointed the tube at such objects as a bag of popcorn kernels and an egg, with similar results in both experiments (the popcorn popped and the egg exploded), he correctly concluded that the observed effects in each case were all attributed to exposure to low-density microwave energy [2]. Shortly after the accidental discovery, engineers at Raytheon went to work on Spencer's new idea, developing and refining it to be of practical use.
In late 1946, this resulted in the Raytheon Company's first patent proposing that microwaves be used to cook food. The following year, the first commercial microwave oven, dubbed the "Radarange," hit the market with a cost between $2,000 and $3,000. Finally in 1965, Raytheon introduced the first countertop domestic oven, much improved in the area of size, safety and reliability than older models with a cost of $500. As fears and myths of these mysterious new "radar ranges" began to fade during the 1970's, public demand began to swell with acceptance until the sales of microwave ovens eventually surpassed those of gas ranges in 1975. Furthermore, in 1976 the microwave became a more common household appliance than the dishwasher as it found its home in nearly fifty-two million U.S. households, or 60% of U.S. homes [2].
Christian Rasmussen/Wikimedia Commons
Figure 1: Modern microwave ovens have come a long way from their original counterparts.