The microwave oven is perhaps the most common kitchen appliance in today’s modern homes. In fact, Popular Mechanics said that about 90% of homes in America have a microwave oven.

That, of course, is pretty understandable.

Everybody loves using the oven for heating popcorns, pork rinds, and many others – especially for busy individuals who are always on the go. It’s very convenient and easy to use.

What you probably don’t know about this indispensable kitchen appliance though is that it was actually invented purely by accident.

The origin of the oven can be traced some 70 years ago when, in 1946, inventor and Raytheon engineer Percy Spencer was testing a military-grade magnetron. He was attempting to improve the power level of magnetron tubes that are intended for radar set use.

When he reached for the peanut cluster bar on his pocket, he found out it has already melted or, in his own words, it was “a gooey, sticky mess.”

The 1958 Raytheon Radarange III, an early version of a commercial microwave oven as invented by Percy Spencer.

George “Rod” Spencer Jr, the grandson of the inventor, shared:

“He loved nature (due to his childhood in Maine)… especially his little friends the squirrels and the chipmunks,” the younger Spencer says of his grandfather, “so he would always carry a peanut cluster bar in his pocket to break up and feed them during lunch.”

Curious with how the bar melted, Spencer again ran a magnetron test, this time putting an egg under the tube. The egg eventually exploded, which further intensified Spencer’s interest. The next day, Spencer brought some corn kernels which became popcorns.

Introduced in 1947, the microwave technology was ahead of its time and only became popular after two decades.

By 1947, Radarange, the first microwave oven, was introduced to the market. It had a weight of almost 750 pounds and had a tag price of over $2,000. At the time, it failed to become a hit among the public.

In 1955, the first domestic microwave was sold but the new technology still didn’t find wide acceptance. It was only in 1967 that Amana introduced a more compact version of the Radarange that it began to attract attention. In fact, 1 million microwave ovens were sold each year around 1975 and onwards.

Rod Spencer, now an engineer himself and currently writing a book about his grandfather, said: