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.

Don't miss a chance to see the Cherenkov radiation effect at your local research reactor.<p><a href="https://en.wikipedia.org/wiki/Cherenkov_radiation" rel="nofollow">https://en.wikipedia.org/wiki/Cherenkov_radiation</a>

You won't make one at home, but cloud chambers[^1] reveal individual alpha particle tracks.<p>There's one in the Musée des Arts et Métiers in Paris — blew my mind!<p>[^1]: <a href="https://en.wikipedia.org/wiki/Cloud_chamber" rel="nofollow">https://en.wikipedia.org/wiki/Cloud_chamber</a><p>Edit: turns out people make these at home <i>all the time.</i> Sick!

I tried the same with bananas. Got nothing.