Oct. 25: The first microwave ovens were sold on this day in 1955

Ask anyone to imagine a microwave oven, and I bet no one would picture a skulking behemoth the size of a fridge—only heavier.

But that was exactly what the very first microwaves looked like.

Later, on Oct. 25, 1955, the first home microwave ovens were sold—emphasis on the word “oven.” These things looked much more like conventional ovens than the traditional countertop microwaves we think of today.

The first microwaves were born by accident in the labs of what is now a massive American defense company called Raytheon. It’s a story of accidental invention that’s almost famous in its own right.

Raytheon engineer Percy Spencer was working on radar technology—think of the kind of radar that was used to track subs in World War II—when he realized that a candy bar in his pocket had melted from the heat of the radar waves. With a pocket full of chocolate goo, he realized that waves could cook food.

His first dish was popcorn, and then eggs.

Capitalizing on its engineer’s efforts, Raytheon patented the technology and created the first Radarange in the late 1940s. The tubes inside had to be cooled with water, so the microwave had to be hooked up to plumbing. It weighed about 760 pounds and stood 6 feet tall and as such, was only used commercially. The cost: $2,000 to $3,000 (that’s about $20,000 today).

The next iteration was the Tappan Stove Co.’s wall unit. This was the first true residential microwave—the one that was first sold in 1955--and it looked more like a built-in oven you see today. It sold for about half the cost of the Radarange and had an impressive two different cooking speeds.

But it basically freaked people out, plus it was still very expensive, so consumers steered clear.

It wasn’t until 1967 that the first popular, modern-looking models were introduced by Amana, which had just recently been acquired by Raytheon. They introduced the countertop Radarange at only cost about $500 (a bit over $3,000 in today’s money). Even though this model is still much more expensive than today’s models, which can sink below $50, consumers were willing to shell out the cash.

The microwave oven became wildly popular, to the point that people were ready to abandon their regular ovens—at least if you believe the authors of the microwave-specific cookbooks that came out in the 1980s.

The microwave never really overtook the oven, but now almost every home in America has one on the countertop (not stacked next to the fridge).

Ilyce Glink is an award-winning, nationally syndicated real estate columnist, blogger and radio talk show host, and managing editor of the Equifax Finance Blog. Follow her on Twitter @Glink.