Comments by "EebstertheGreat" (@EebstertheGreat) on "Pressure lamps: gaslighting on the go" video.

@xWood4000 This contradicts some pretty authoritative sources (e.g. the CDC, Harvard, the EPA, and many research papers). According to Harvard, a single sheet of 20-lb bond paper was enough to stop all of the alpha radiation in their demo. In Thought Emporium videos, he talks about the risks of inhaling thorium. That said, thorium does release gamma radiation as well, in very small quantities, from its daughter products. Incidentally, the epidermis is (mostly) living tissue. Squamous cell carcinoma is a thing. The layer of dead skin cells at the surface (the stratum corneum) is only around 20 microns thick, which is not enough to stop all alpha radiation. So don't paint alpha emitters onto the underside of your wrist watch is all I'm saying.
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@xWood4000 Thorium and uranium are the likely sources of alpha particles for school demos, since they are much cheaper and safer than alternatives like radium, polonium, and americium. I found the video you were talking about, and I'm not sure why the paper did not stop all the alpha particles, though it did stop many of them. One commenter suggested it could be caused by radon diffusing around the edge of the paper. Whatever the case, a cloud chamber is certainly a more sensitive detector than we would normally see.
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@xWood4000 In many cases it's probably just some rock with thorium and uranium among a bunch of other heavy metals. For instance, you could get a decent-sized hunk of monazite for a few bucks, and it contains some thorium. There are minerals and industrial products much more abundant in thorium though. Thorium is common and very cheap at low purity.
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@zoravar.k7904 That's gamma radiation, not alpha. The Geiger counter can't even detect alpha radiation the way he's using it.
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