A Brief History of Microwave Oven
and from the video You Can Fix Your Microwave Oven, Plus VCR Know-How
By J. Carlton Gallawa, author of The Complete Microwave Oven Service Handbook
Like many of today's great inventions, the microwave oven was a by-product of another technology. It was during a radar-related research project around 1946 that Dr. Percy Spencer, a self-taught engineer with the Raytheon Corporation, noticed something very unusual. He was testing a new vacuum tube called a magnetron, when he discovered that the candy bar in his pocket had melted. This intrigued Dr. Spencer, so he tried another experiment. This time he placed some popcorn kernels near the tube and, perhaps standing a little farther away, he watched with an inventive sparkle in his eye as the popcorn sputtered, cracked and popped all over his lab.
The next morning, Scientist Spencer decided to put the magnetron tube near an egg. Spencer was joined by a curious colleague, and they both watched as the egg began to tremor and quake. The rapid temperature rise within the egg was causing tremendous internal pressure. Evidently the curious colleague moved in for a closer look just as the egg exploded and splattered hot yoke all over his amazed face. The face of Spencer lit up with a logical scientific conclusion: the melted candy bar, the popcorn, and now the exploding egg, were all attributable to exposure to low-density microwave energy. Thus, if an egg can be cooked that quickly, why not other foods? Experimentation began...
Dr. Spencer fashioned a metal box with an opening into which
he fed microwave power. The energy entering the box was unable
to escape, thereby creating a higher density electromagnetic field.
When food was placed in the box and microwave energy fed in, the
temperature of the food rose very rapidly. Dr. Spencer had invented
what was to revolutionize cooking, and form the basis of a multimillion
dollar industry, the microwave oven.
The microwave oven had reached a new level of acceptance, particularly
with regard to certain industrial applications. By having a microwave
oven available, restaurants and vending companies could now keep
products refrigerator-fresh up to the point of service, then heat
to order. The result? Fresher food, less waste, and money saved.
By 1975, sales of microwave ovens would, for the first time, exceed that of gas ranges. The following year, a reported 17% of all homes in Japan were doing their cooking by microwaves, compared with 4% of the homes in the United States the same year. Before long, though, microwave ovens were adorning the kitchens in over nine million homes, or about 14%, of all the homes in the United States. In 1976, the microwave oven became a more commonly owned kitchen appliance than the dishwasher, reaching nearly 60%, or about 52 million U.S. households. America's cooking habits were being drastically changed by the time and energy-saving convenience of the microwave oven. Once considered a luxury, the microwave oven had developed into a practical necessity for a fast-paced world.
An expanding market has produced a style to suit every taste;
a size, shape, and color to fit any kitchen, and a price to please
almost every pocketbook. Options and features, such as the addition
of convection heat, probe and sensor cooking, meet the needs of
virtually every cooking, heating or drying application. Today,
the magic of microwave cooking has radiated around the globe,
becoming an international phenomenon.
On September 18, 1999, Dr. Percy LaBaron Spencer was inducted into the National Inventors Hall of Fame and took his place in history alongside such great inventors as Thomas Edison, the Wright Brothers and George Washington Carver.
Note: Photo of Percy Spencer and Patent provided
courtesy of The Spencer Family Archives
Picture of Original Microwave Oven Patent by Doctor
Percy L. Spencer