If you haven't experienced a spinthariscope, I can highly recommend it. I bought one as a Christmas present for a buddy and we both enjoy its demonstration of radioactivity.
You won't make one at home, but cloud chambers[^1] reveal individual alpha particle tracks.
There's one in the Musée des Arts et Métiers in Paris — blew my mind!
[^1]: https://en.wikipedia.org/wiki/Cloud_chamber
Edit: turns out people make these at home all the time. Sick!
You can easily make them at home (source, I did last weekend!). - Dry ice (mine came from something shipped cold) - Dark piece of metal (I used a 3D printer hot bed) on top of dry ice to get cold - IPA vapour (I poured some on a shop towel) - Some transparent container to house it all - I found a glass display cube on the side of the road, fish tanks or Tupperware also work. - Torch or something to provide side lighting Very cool to see evidence of the particles zooming around us, can highly recommend.
This can be done at home with a little effort. Less effort if you can get dry ice easily.
https://hackaday.com/2019/01/13/see-the-radioactive-world-wi...
Well, google for "DIY cloud chamber" did result in quite some entries. Apart from youtube channels, with the first entry a guide from CERN:
https://home.cern/news/news/experiments/how-make-your-own-cl...
Don't miss a chance to see the Cherenkov radiation effect at your local research reactor.
I tried the same with bananas. Got nothing.
Bananas are like XML that way. If you're not getting the results you want, you're just not using enough of them.
Potassium-40 is not an alpha emitter.
Maybe he used banana as the scintillator.
That's unrelated. He's been diligently substituting bananas in many experiments to mostly disappointment.