12. Microwave
Since its discovery in mid-20th-century microwaves had become an inevitable part of homes in the US. The man behind this invention is Percy LeBaron Spencer who was a self-taught engineer who worked on magnetrons, vacuum tubes used in radar systems which produce microwave radiations. So, one day he realized that when working with the magnetron, chocolate in his pocket had melted. Then he realized it could have been due to the microwaves, and he started putting different foods in the magnetron, realizing that they are being cooked faster than in the normal oven. And since microwave radiation cannot pass through metal, he then designed a metal box that emitted microwaves.
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