American engineer known for his work in inventing the microwave oven. While working with radar equipment he noticed that candy in his pocket had melted. Radar detects objects by bouncing microwaves from them. Spencer he realized that it was the microwaves themselves that had melted the candy. In 1945 his microwave oven was commercially available, known as a radarange. The first microwave prototypes were large, cumbersome, and expensive.