I’m sure everyone is familiar with a microwave oven. I’ll bet many of you used one in the past two hours. What was once a luxury is now a kitchen necessity. But do you know the backstory on the microwave oven? It’s one of those odd, serendipitous, happenstance kind of inventions. Like Alexander Fleming and penicillin. And Thomas Adams and chewing gum. Or James Wright and Silly Putty. It’s one of those “right place, right time” kind of inventions. And the inventor had the insight to recognize the potential of what he discovered. Here’s the skinny on the microwave oven.
So, first of all, a microwave oven uses electromagnetic radiation in the microwave frequency range to induce polar molecules in food to rotate and produce thermal energy. It’s known as dielectric heating. Back in World War II, Raytheon produced combat radar equipment that used their vacuum power tube designs. And this guy, Percy Spencer, who was the chief of Raytheon’s power vacuum tube division during the war, developed an efficient way to manufacture magnetrons, which were used to generate microwave radio signals – the core mechanism of radar. As you can imagine, microwave radio signals – radar – was incredibly important to the war efforts.
Anyway, one day, ol’ Percy was standing around near an active radar set when he looked in his shirt pocket and noticed his candy bar had completely melted. As the story goes, this wasn’t the first time someone noticed a chocolate bar melting when someone stood in front of a radar set, but Percy was the only one who decided to do some investigation and figure out what was going on. And here is a fun fact inside of a fun invention story – the first food he decided to experiment with was popcorn kernels! That’s right, he made the first microwaved popcorn. How cool is that?
Anyway, Percy attached a high-density electromagnetic field generator to an enclosed metal box and viola – the microwave oven was invented and patented in 1945. Raytheon released the “Radarange” microwave oven in 1947 – which stood over 6 feet tall, weighed 750 pounds and cost between $2000 and $3000. It would be decades before the size and cost would come down to where microwave ovens became a reality for households across the globe.
Percy Spencer went on to receive more than 300 patents in his lifetime. Another fun fact – Percy had no formal education. Raised by a poor uncle, he joined the Navy when he was 18 and learned about wireless communications. He taught himself trig, calculus, physics, metallurgy and chemistry and became an expert on radio technology. That led him to vacuum tube technology, which led him to radar equipment and magnetrons. Which led to the world’s first microwave oven. Pretty cool stuff.
Now go “zap” some popcorn.