Chocolate in His Pocket

In nineteen forty five, engineer Percy Spencer found that a chocolate bar had melted inside his pocket. He was testing a magnetron, a device that generates microwaves for radar equipment. Suspecting the machine, he placed popcorn kernels beside it and watched them burst. A later egg test reportedly exploded, showing that rapid heating could be hazardous. Together, the tests showed that the machine's waves, not ordinary warmth, had heated the food. Those waves made water molecules rotate, transferring energy into heat within the food. Food shape and oven design affected how evenly that heat spread. A commercial oven reached restaurant kitchens in nineteen forty seven, although few homes could afford one. The first models were so large and costly that ordinary kitchens were effectively excluded. As appliances shrank, home cooks could warm a single serving without lighting a stove. For families, the deeper change was not faster cooking, but being able to eat at different times.