Microwave oven
In 1945, the heating effect of a high-power microwave beam was accidentally discovered by Percy Spencer, an American self-taught engineer from Howland, Maine. Hired by Raytheon at the time, he noticed that microwaves from an active radar set he was working on started to melt a chocolate bar he had in his pocket. First, Spencer deliberately cooked popcorn with a microwave oven. And the second time, he cooked an egg, which exploded in the face of one of the experimenters.