The demon core was a spherical 6.2-kilogram (14 lb) subcritical mass of plutonium 89 millimetres (3.5 in) in diameter, that was involved in two criticality accidents, on August 21, 1945 and May 21, 1946. Wikipedia: Demon core
Now you can have fun without the death-risk in the comfort of your home.
Meet the party-core:
If you’re interested in this topic I can recommend a book:
Atomic Accidents: A History of Nuclear Meltdowns and Disasters: From the Ozark Mountains to Fukushima
A “delightfully astute” and “entertaining” history of the mishaps and meltdowns that have marked the path of scientific progress (Kirkus Reviews, starred review).
About a year ago there were some very interesting reports about a german inventor and his invention: a highly futuristic, transforming smartphone airbag.
It would be attached to your phone and when you drop it, it would automatically deploy and dampen the impact.
Impressive, right? There’s now a Kickstarter campaign behind this to deliver it as a product. All very nice and innovative.
I have no usue of a smartphone airbag of some sort. But hear me out on my train of thought:
I do partake in the hobby of quadcopter flying. I’ve built some myself in the past.
Now these quadcopters are very powerful and have very short flight times due to their power-dynamics. 4-5 Minutes and you’ve emptied a LiPo pack.
Model airplanes, essentially everything with wings, flys much much longer.
My thought now: Why not have a convertible drone.
When the pilot wants a switch could be flipped and it would convert a low-profile quadcopter to a low-profile quadcopter with wings. Similar to how the above mentioned smartphone “airbag”.
I don’t know anything about mechanics. I have no clue whatsoever. So go figure. But what I do know: the current path of the mini-quad industry is to create more powerful and bigger “mini”-quadcopters. And this is a good direction for some. It’s not for me. Having a 10kg 150km/h 50cm projectile in the air that also delivers a 1kg Lithium-Polymer, highly flammable and explosion-ready battery pack does frighten me.
Why not turn the wheel of innovation into the convertible-in-air-with-much-longer-flight-times direction and make the mini-quadcopters even more interesting?
If you ever traveled on a train or plane with good active noise cancellation headphones you might agree how much more pleasant the trip was with much less noise reaching your ears.
When I tried active noise cancellation for the first time I had that weird sensation as if the pressure around suddenly changed. Like being in a very fast elevator or going for a quick dive. It felt weird but luckily it went away and the aww of joy replaced it. Quietness. Bliss.
Now there seem to be people for whom that feeling won’t go away. They get headaches and cannot stand the feeling when using active noise cancellation.
I’ve never had any explanation to this phenomena – until now. I ran across an article on SoundStage describing that in fact the feeling is not caused by actual changes of pressure but…
According to the engineer, eardrum suck, while it feels like a quick change in pressure, is psychosomatic. “There’s no actual pressure change. It’s caused by a disruption in the balance of sound you’re used to hearing,” he explained. eardrum suck – the mystery solved
Aha! The brain gets confused by signals reaching your ears that naturally would not exists. Those signals make no sense so the brain tries to make sense of it. And voilá something is sucking your ear drum!