The microwave oven was an accidental discovery by Percy Spencer, an engineer working for Raytheon. While standing in front of an active radar set (a magnetron), he noticed that a chocolate bar in his pocket had melted. Intrigued, he placed popcorn kernels near the magnetron, and they popped. The first commercial microwave, the 'Radarange,' was released in 1947; it was six feet tall and weighed 750 pounds. Microwaves work by producing electromagnetic waves that cause water molecules in food to vibrate rapidly. This vibration creates friction, which produces heat. Unlike conventional ovens that heat from the outside in, microwaves penetrate food to a depth of 1-2 inches, causing internal heating. This significantly reduced cooking times for everyday meals.