We’ve all heard the story that the microwave was invented around WW2, when an American working on one of the big Air Force radars noticed that radiation melted a chocolate bar in his pocket but didn’t cook him.
That sounds like a great story, but it can’t be true, right? It’s got to be one of those internet factoids that was invented as click-bait 15 years ago, and just keeps getting repeated, right?
Percy Spencer was an engineer for Raytheon, a huge American defence contractor in 1945. According to Spencer himself, he was working on a microwave radar set (it was turned on at the time, but apparently there were no health and safety standards back then) and the foil-wrapped candy bar in his pocket started to heat up and melt. He felt the hot chocolate, but not the radiation, and jumped back, apparently unharmed. There is a short feature about it here.
Being an inventor of the old, mad scientist school, he took his huge, poorly-shielded microwave source and tried it on other foods. It popped popcorn (according to Spencer, this was not attempted whilst in his trouser pocket) and exploded an egg ‘right into the face’ of another engineer.
Let me say that again, because you might have missed it…
The engineer had his face right up near the egg they were cooking with a big, military radar emitter.
Somehow, none of them turned into the Hulk or cooked their own eyes.
A few years later, Raytheon was gearing up for the post-war market with a six foot tall, 3000 watt monster called the RadaRange. It cost something like £34,000.00 in today’s money.
They say it could cook fry an egg in 12 seconds. Good luck getting a qualified repairman to come out in 1948 if you left it in for an utterly irresponsible 20 seconds though. I wonder what a new magnetron would have set you back, if you tried to fix it yourself?
What can I say? They got smaller, ad a lot less frightening. By the late 60’s the Amana company, owned by Raytheon, had a small, low-power countertop model that cost substantially less than a new Cadillac. The microwave we know was born.