The Candy Bar That Invented the Microwave Oven
Tech Curiosity — Saturday, August 1, 2026 The Candy Bar That Invented the Microwave Oven How a melted chocolate bar in an engineer's pocket rewired the modern kitchen 🍫 A Melted Pocket, A Radar Lab, A Question Nobody Had Asked In 1945, an engineer named Percy Spencer was standing in front of an active magnetron — the vacuum tube at the heart of military radar systems — inside a Raytheon lab in Waltham, Massachusetts. Spencer had spent years around radar equipment, first as a self-taught technician who never finished grade school, and had built a reputation for noticing things other engineers walked past without a second look. That habit was about to pay off in the strangest possible way: the candy bar in his shirt pocket had turned to liquid. Most people would have written it off as body heat or a coincidence. Spencer instead treated it as a clue. He reasoned that the microwaves radiating from the magnetron — the same waves used to detect...