One day in the mid-1940s, Raytheon employee Percy Spencer was working with an active radar set when he noticed that a candy bar in his pocket had melted. Spencer got some popcorn, put it in proximity of the magnetron tube that generated the microwaves for the radar, and was soon enjoying a tasty snack. Raytheon received a patent for the microwave oven in October 1945 and built the first Radarange (the name was submitted during an employee contest) two years later—yet the microwave oven didn't become a must-have appliance until the mid-1970s. Why?

Size, for one thing. We're used to the petite but powerful microwave ovens that nestle on our kitchen counters, but early models were behemoths that varied in size "from a unit smaller than a home refrigerator to one somewhat larger," according to the New York Times in 1946. Pictured is one of the more compact models from 1947; a demonstration model from 1949 was five feet high, two feet wide, and two feet deep.


Price was another problem. In 1949, the magnetron tube alone cost $500 to manufacture (roughly $4400 today), thus the first generation of microwave ovens were marketed for restaurant and industrial use. A Radarange for the home was introduced in 1955 but at $1,875 for a tabletop model and $2,975 for a wall console ($14,500 and $23,000, respectively, in today's currency), it was prohibitively expensive for all but the most well-heeled consumers.

There were other drawbacks, too. The Times noted in 1946 that baked goods were crustless and roasts "gray rather than brown." But it was fast, fast, fast! Microwaves cooked steak dinners in 35 seconds, hot dogs in buns in 15 seconds, and baked gingerbread from batter in 26 seconds. A 1962 Raytheon ad imagined what this meant to the harried housewife:

Four unexpected guests for dinner? Mother better set the extra places at table first or the food will be ready before she is. Popping four large potatoes in to bake will give her just two minutes before they are steaming, fluffy, ready to serve. And the juicy, tender, mouth-watering sirloin steak with which she wants to impress her guests will be done to a turn in nothing flat. Twenty seconds to be exact!


Who cared if the meat was gray? This was the modern world in action!

Even so, sales didn't take off until the mid-1970s, when technological advances led to lower prices and more compact ovens—and the American public learned that the microwave was best suited for reheating leftovers and frozen foods than cooking gourmet meals.