On this day in 1955, the first domestic microwave oven is introduced. But the microwave’s origins were anything but domestic.
Like many other inventions, the microwave oven was invented almost by accident, because of wholly different technology. In the early years of World War II, in the labs of what is now one of the world’s largest defense companies, Raytheon, engineer Percy LeBaron Spencer was testing a magnetron, an electron tube that generated microwaves that could help British radar systems detect Nazi warplanes. As he was working on the active radar set, Spencer noticed something unusual–the microwaves had melted a candy bar in his pocket. Excited he had discovered a new use for the technology, he placed some popcorn kernels near the magnetron and stood back as the popcorn sputtered and popped all over the lab. The next day, he brought in an egg and watched with a colleague as the egg quaked and exploded, splattering hot yolk all over his face.
Spencer began experimenting. He built a metal box into which he fed microwave power, thereby trapping the microwaves and creating a higher density electromagnetic field. When food was placed in the box and microwave energy fed into it, the temperature of the food rose very quickly, cooking the food in seconds and minutes. Spencer had revolutionized cooking. By 1945, Raytheon had filed a patent for the microwave cooking process. By 1947, it built the Radarange, the world’s first microwave oven.
The first microwave oven was nearly six feet tall, about 340 kilograms (750 lb), and cost about $5000 US. The magnetron’s tubes had to be cooled by water, so plumbing was also installed. It was, unsurprisingly, not well-received. But Raytheon kept improving the microwave, introducing the 1161 Radarange in 1954, the first commercial microwave oven. It was between $2000 and $3000 US. Raytheon then licensed the technology to the Tappan Stove Company, which introduced a 220-volt home microwave oven in 1955 that sold for $1295. It was a wall unit with a stainless steel exterior, glass shelf, top-browning element, and a drawer for recipe cards. Sales were still slow.
In the 1960s, the microwave grew in leaps and bounds. A company called Litton Industries designed the short, squat microwave we’re familiar with today. As prices began to drop rapidly, consumer interest grew. By 1967, a countertop Radarange cost $495 US. In 1970, 40,000 microwave ovens were sold in the US. By 1975, it was a million, exceeding sales of gas ranges. The microwave became a fixture in American kitchens.
As for Spencer, he continued working in Raytheon until he was 76. Though he was a self-taught engineer who never completed high school, by the time he died, Spencer had acquired 150 patents. In 1999, he was inducted into the National Inventors Hall of Fame alongside Thomas Edison, the Wright Brothers, and George Washington Carver.
Credit: Corbis U1295557INP
Caption: Mrs. Joanne Meese holds her child as she prepares baby food in a microwave oven in 1955.