Radar

The Yagi-Uda antenna, invented in Japan in 1926, was vital for radar, but Japan ignored it. Britain used it to gain a decisive edge in World War II. At Singapore, Japanese soldiers found "Yagi" in a British technician's notes—and asked him what it meant.

In 1945, engineer Percy Spencer noticed his chocolate bar had melted near a radar device. He tried popcorn—it popped. An egg exploded. Realizing microwaves heated water molecules, he patented the idea, and the world's first microwave oven was born.