Just about everyone knows the story of the first microwave oven. It's one of the all-time great "accidental" discoveries of science.
For those that don't, in the 1940s, engineer Percy Spencer was working at Raytheon (everything back then was named as though it was one day to appear in Fallout) when he was testing an active radar, while he had a chocolate bar in his pocket. At some point, he noticed that the chocolate had melted into his pocket. Rather than merely changing his trousers, he realized the potential to heat food using a high-density electromagnetic field (and presumably also changed his trousers).
He first experimented by getting a bag of popcorn, and attempting to heat that. It worked. He pushed his luck and tried to heat an egg, which exploded spectacularly, thus also inventing the "don't put an egg in the microwave" rule.
Spencer next worked on putting magnetrons (which create microwave radiation) inside a faraday cage (which blocks electromagnetic fields). The result was a massive microwave oven – around the size of a fridge – which Raytheon began to sell commercially to restaurants in 1947, at $5,000 (around $60,000 today). However, the microwave was not widespread until it was made smaller and cheaper, which wouldn't really happen until the late 1960s-early 1970s.
In the meantime, as YouTuber Tom Scott explains in a new video that's taken the video site by storm, microwaves were put to a little heard of use throughout the 1950s: microwaving dead hamsters in an attempt to reanimate them back to life.
In the 1940s, scientists spent more time than you'd be comfortable with freezing hamsters and rats to death before attempting to resuscitate them by applying heat. They weren't just playing Hampenstein, the goal was to be able to revive tissue after freezing, something which would have obvious applications in storing blood and organs.
The success rate was pretty low, however, and those that did come back to life were left with horrendous burns. Scientist James Lovelock saw a colleague who had been reviving hamsters and suggested a better method.
"One biologist, Audrey Smith, was able to revive a hamster that had been frozen," Lovelock, now 101, told Scott in the video above. "When they woke up they got a gigantic burn across their chests."
"That must have been pretty painful, and it was messy. I thought it was a lousy way to do it, so I said 'why don't you use diathermy?'"
Though using microwave radiation for heating food was relatively new, diathermy – using electromagnetic currents in order to produce heat as a form of therapy – had been around since the late 1800s. Using his own money, Lovelock bought a disused Royal Air Force transmitter for use in further experiments.
He disliked how untidy the transmitter looked, and instead acquired some magnetrons, using some government contacts. He placed the magnetrons inside a box containing a faraday cage of chicken wire, creating what was essentially like a modern-day microwave oven, independently of Percy Spencer.
"I told Audrey, 'now put your hamster in there'."
It was, surprisingly, quite successful, and the team would publish several papers on the topic, including "Reanimation of rats from body temperatures between 0 and 1° C by microwave diathermy". The paper describes how the new technique of microwaving rats instead of heating them with a hot metal spatula improved the revival rate dramatically, with 80-100 percent of the rats recovering following the cooling.
"We put the hamster in there, frozen solid," he said in the video of his first attempt. "Turned the thing up to full power on the microwave [...] and after so many seconds the hamster woke up and started wandering around."
In one case, they describe how "a single rat was reanimated 10 times after being cooled at intervals of 2-10 days each time" like Beric Dondarrion from Game of Thrones, but a rat.
The rats were kept under observation and remained healthy seven months after their ordeal. I imagine you're now thinking "can we just microwave grandma then" and, sadly, no. As Lovelock explains, it doesn't scale up, because you essentially can't freeze nor heat an animal of our size quickly enough, nor diffuse an antifreeze agent into the cells fast enough.
Though Lovelock didn't attempt to commercialize his version of a microwave in the same way as Spencer, he did see that it applied well to food, and microwaved a potato inside it (hopefully after cleaning off the dead hamster) and described it as "perfectly alright".
[H/T: Tom Scott]