During World War II, workers at technology company Raytheon were designing and creating the magnetron tubes used in U.S. and British radars. Standing in front of one of these magnetrons one day, inventor Percy Spencer noticed a candy bar in his pocket started to soften. Most people would’ve cursed the chocolate-melting device, but he decided to see what would happen with other foods, including corn kernels and eggs. The microwave was born out of these observations (though Raytheon called the first iteration the “Radarange”), but the first consumer version didn’t appear until 1955 and only 1 percent of U.S. households owned one in 1971.
How the now-ubiquitous machines work is still a mystery to many people who own them. In order to shed a little light on the appliance, ChefSteps made a YouTube video.
Microwaves still have magnetrons, or vacuum tube, in them, and when you press the power button, they send out electromagnetic waves, better known as microwaves. Everything happens inside an insulated chamber, so the microwave radiation doesn’t escape. A waveguide then directs the microwaves to the food, and a fan scatters the beam into several, so a greater amount of the food gets cooked.
The video ends there, making it a short and sweet explanation. If you want to know a little more, you can check out this 2012 video from Bill Hammack, a professor in the Department of Chemical Engineering at the University of Illinois at Urbana-Champaign. He further explains how a microwave differs from other cooking methods: “In a traditional oven or stove, we heat food by placing a pan on a burner or in the oven where the walls radiate heat, which cooks the outside of the food. The insides cook when heat transfers from the surface of the food to its interior.”
With a microwave, “energy from the magnetron penetrates into the food, which means the whole mass of the food can be cooked simultaneously.” The professor even goes on to explain why your microwave will make some parts of your flatbread piping hot while leaving other spots ice cold.
Frankly, we’ll never look at our bag of popcorn/unpopped kernels the same way again.