In 1945, Percy Lebaron Spencer, an engineer and the creator of America, busy working at the factory magnetron, a device used to produce the microwave radio signals, which is an early form of radar. Radar is an incredibly important innovation during the war, but this microwave signals accidentally initiate the use of microwaves to cook food.
While he was standing near a magnetron which is turned on, Spencer found that chocolate bar melted in his pocket.
His smart brain then start to think of it is due to microwaves. Then she tried it on popcorn seeds, and then on an egg to explode. The first microwave oven weighed about 340 pounds with a size of a refrigerator.