In 1947, the American company Raytheon introduced the first commercial microwave oven, called the Radarange. Weighing 340 kilograms and standing 1.8 meters tall, this early model was not for home use. It cost between $2,000 and $3,000, making it affordable only for restaurants, cruise ships, and large institutions. The microwave's origins trace back to a chance discovery in 1945 by Percy Spencer, a self-taught engineer working at Raytheon’s laboratory in Waltham, Massachusetts. Spencer was tasked with improving magnetrons, components used to generate microwaves for radar systems. One day, while standing near an operating magnetron, he noticed that a chocolate bar in his pocket had melted. Fascinated by this unexpected phenomenon, Spencer experimented further, testing other foods like popcorn and eggs. He found that microwaves agitate water molecules in food, creating friction that generates heat from within, rather than from an external source. This discovery sparked the idea of using microwaves for cooking, and Raytheon quickly filed a patent for the technology. The first Radarange model, launched in 1947, was far from the compact devices we know today. Its size—comparable to an upright piano—meant it was impractical for home kitchens. As a result, the microwave remained a niche product for years, with sales kept confidential. It wasn’t until 1967 that the microwave began to enter American homes in a significant way. This change came with the launch of the Amana Radarange, a compact model developed after Raytheon acquired Amana Refrigeration in 1965. Priced at $495, this model was much more accessible, though still expensive by today’s standards. Despite this breakthrough, microwave ovens did not immediately become common household items. It wasn’t until the mid-1970s that they gained widespread popularity, surpassing gas ovens in sales in 1975. Today, microwave ovens are small, lightweight, and fit easily in kitchen drawers, a stark contrast to the 340 kg behemoth of 1947. While Percy Spencer never received royalties for his invention, his accidental discovery has left a lasting impact, making the microwave one of the most commonly used household appliances in the world.