Sometimes all you really need to make the next leap in science is a snack. Percy Spencer was an American engineer who, while working for Raytheon, walked in front of a magnetron, a vacuum tube used to generate microwaves, and noticed that the chocolate bar in his pocket melted. In 1945 after a few more experiments (one involving an exploding egg), Spencer successfully invented the first microwave oven. The first models were a lot like the early computers: bulky and unrealistic. In 1967, compact microwaves would begin filling American homes.