Radioactive decay Updated 2025-07-16
Ciro Santilli finds it interesting that radioactive decay basically kickstarted the domain of nuclear physics by essentially providing a natural particle accelerator from a chunk of radioactive element.
The discovery process was particularly interesting, including Henri Becquerel's luck while observing phosphorescence, and Marie Curie's observation that the uranium ore were more radioactive than pure uranium, and must therefore contain other even more radioactive substances, which lead to the discovery of polonium (half-life 138 days) and radium (half-life 1600 years).
Isotope Updated 2025-07-16
Figure 1.
Neon isotope line split photograph by J. J. Thomson
. Source. J. J. Thomson took this picture in 1912:
There can, therefore, I think, be little doubt that what has been called neon is not a simple gas but a mixture of two gases, one of which has an atomic weight about 20 and the other about 22. The parabola due to the heavier gas is always much fainter than that due to the lighter, so that probably the heavier gas forms only a small percentage of the mixture.
Nuclear weapon Updated 2026-08-21
Figure 1.
A weapons-grade ring of electrorefined plutonium, typical of the rings refined at Los Alamos and sent to Rocky Flats for fabrication
. Source. The ring has a purity of 99.96%, weighs 5.3 kg, and is approx 11 cm in diameter. It is enough plutonium for one bomb core. Which city shall we blow up today?
Ciro Santilli is mildly obsessed by nuclear reactions, because they are so quirky. How can a little ball destroy a city? How can putting too much of it together produce criticality and kill people like in the Slotin accident or the Tokaimura criticality accident. It is mind blowing really.
Video 1.
Tour of a nuclear misile silo from the 60's by Arizona Highways TV (2019)
Source.
Video 2.
The Ultimate Guide to Nuclear Weapons by hypohystericalhistory (2022)
Source. Good overall summary. Some interesting points:
Nonprofit impact measurement Updated 2025-07-16
It is harder to measure the impact of nonprofits than of for-profits, since you can't just look at their bank balances.
This is one fundamental difficulty of nonprofit work, how to prove that you deserve the investments and not someone else.
Understand and explain amazingly every single Nobel Prize in physics, chemistry and biology. Since in particular the Nobel Foundation is unable to do that for any at all, especially of the key old ones, e.g. www.nobelprize.org/prizes/physics/1965/summary/. Hopeless.
To be fair, those in theoretical physics at least basically come down to reading a bunch of books. But perhaps anything slightly more experimental could have
Liquid nitrogen Updated 2025-07-16
77K. Low enough for "high temperature superconductors" such as yttrium barium copper oxide, but for "low temperature superconductors", you need to go much lower, typically with liquid helium, which is likely much more expensive. TODO by how much?
Video 1.
Where Do You Get Liquid Nitrogen? by The King of Random (2016)
Source. He just goes to a medical gases shop in a local industrial estate and buys 20L for 95 dollars and brings it back on his own Dewar marked 35LD.
Video 2.
Making Liquid Nitrogen From Scratch! by Veritasium (2019)
Source. "From scratch" is perhaps a bit clickbaity, but I'll take it.
Force Updated 2025-07-16
Mass Updated 2025-07-16

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