The microwave was born from a chocolate bar

In 1945, Percy Spencer, an engineer at Raytheon, was testing a magnetron, the heart of military radar. Standing next to the device, he noticed that the chocolate bar in his pocket had completely melted. Instead of wiping it off and moving on, he did what a good engineer would: he brought in corn kernels, which burst into popcorn, and an egg, which exploded in a colleague's face.

Raytheon patented the system that same year and in 1947 launched the first commercial microwave oven, the Radarange: nearly two metres tall, around 340 kilos, and outrageously expensive. Nobody wanted one at home.

It took decades for it to shrink and get cheap enough to conquer the kitchen. Spencer, who left school as a boy and taught himself electronics, ended up with more than a hundred patents. And it all started with a sticky pocket.