A chocolate bar melting in his pocket led straight to the microwave oven

In 1945, Raytheon engineer Percy Spencer was testing an active radar magnetron when he noticed a candy bar in his pocket had turned to liquid. Instead of shrugging it off, he pointed the tube at popcorn kernels, then an egg, and confirmed the microwaves cooked food fast. Within two years, Raytheon built the first commercial microwave oven, a 750-pound cabinet called the Radarange.

— Percy Spencer, Method of Treating Foodstuffs (US Patent 2,495,429) — Filed 1945, granted 1950