On May 21st, 1946, Louis Slotin was playing around with his exposed nuclear bomb core using a screwdriver and a half-shell of beryllium at a secret base in New Mexico. This core was fittingly called “The Demon Core” and was planned to be used in a canceled nuclear bomb to be dropped on Tokyo.

 It’s important to note that Louis Slotin was one of the leading nuclear physicists in the world. He helped assemble the first nuclear bomb, and graduated from the University of Manitoba at just 16 years old. Despite his accomplishments, Louis Slotin would make the stupidest mistake that would end his and several others’ lives on this day.

  The procedure was simple, Louis was to lower the shell of beryllium onto the core of plutonium in order to get it close to criticality as a demonstration to a new scientist hired to replace him. This was called “tickling the dragon’s tail”. This shell was called the tamper, and equipped with a bottle of Coca-Cola, and a nearby camera-man, nothing should have gone wrong; except for the fact that the tamper was being kept from being fully connected by a long flathead screwdriver. This is called “being critically stupid” and is surprising to see a top physicist make such a weird decision.

  As anyone would expect, the screwdriver did not hold and slipped, causing the core to go critical and blast everyone in the room with a blue flash that sent out over 3 quadrillion fission reactions before the screwdriver was put back in. Louis was said to have stated “Well, that does it.” before dying of organ failure 9 days later.

  The weirdest part of this story is that Louis should have seen this coming. Only a year prior, he had witnessed another colleague die after performing a similar stunt. His boss (Enrico Fermi) had even told him “You’ll be dead within the year if you keep doing that”, yet Louis decided to continue performing these dangerous experiments without regard for proper safety.

txetures from


Bacher, Robert F. "You Don't Know Fat Man." Interview by Lillian Hoddeson and Gordon Baym. The Nuclear Secrecy Blog, Alex Wellerstein, 28 Nov. 2011, Accessed 20 Mar. 2024.

"Manhattan Project Scientists: Louis Alexander Slotin." National Park Service,

Platts-Mills, Ben. "How a Careless Slip Killed a Physicist." BBC, 19 July 2023, Accessed 21 Mar. 2024.

Wellerstein, Alex. "The Demon Core and the Strange Death of Louis Slotin." The New Yorker, Accessed 21 Mar. 2024.


 Strangely enough, I couldn't find many first hand accounts of the event itself. It seems to be one of those stories that get passed down orally, or maybe all the first hand accounts are just sitting in old newspapers that I couldn't find.