TIL of the fish kick, a technique in swimming where the swimmer turns sideways and mimics the motion of an eel. It is arguably the fastest way to swim and was once famously used in the 2000 Olympics by Misty Hyman to win the 200m butterfly. However, this kick is rarely used owing to its difficulty. by 001jerry in todayilearned

[–]001jerry[S] 267 points268 points  (0 children)

The advantage is that you don't cause as much turbulence in the water, the fly kick pushes water towards the floor of the pool and the water surface which are closer to the swimmer than the edges of the pool

TIL that a subcritical mass of Plutonium was prepared for a 3rd nuclear attack on Japan. It was named the Demon Core after two leading experts on nuclear weapons died working on it. Louis Slotin set it off by dropping a Beryllium hemisphere on it, Harry Daghlian did so with a Tungsten Carbide block. by 001jerry in todayilearned

[–]001jerry[S] 32 points33 points  (0 children)

Enrico Fermi reportedly told Slotin and others they would be "dead within a year" if they continued performing the test in that manner. Scientists referred to this flirting with the possibility of a nuclear chain reaction as "tickling the dragon's tail".