The spinthariscope was a popular amusement at academic parties in the early 1900s, or so I am told. It consists of a short tube with a lens at one end and a zinc-sulfide coated screen at the other, with just a touch of radium mounted near the screen. You look through the lens and see tiny flashes of light on the screen, each one caused by the impact of a single alpha particle created by the decay of a single atom of radium.
This is a rather cheaply made one from a Chemcraft chemistry set made in the 1950's. Unfortunately while the radium will remain radioactive for millennia, the zinc-sulfide phosphor does not last very long, and most spinthariscopes, including this one, do not work very well anymore. By turning off all the lights, covering myself in a thick blanket, and letting my eyes adjust to the dark for a good 5-10 minutes, I was able to convince myself that I saw real flashes of light, one every couple of seconds and sometimes a burst of half a dozen all at once. Whether this was due to radium decay or oxygen deprivation I'm not entirely sure.
Here is an article about spinthariscopes.
Amazingly, there is a revival of spinthariscopes on eBay: Check out my modern spinthariscope for details.
I got the 1950's chemistry set on eBay after consulting this trusty reference book about radioactive collectables. According to its table of going rates for these things, I got a good deal on the chemistry set, though it is not in perfect condition and is missing some components. Modern chemistry sets are pretty wimpy, but I have to say that, aside from the uranium ore and the radium, this set is pretty tame as well. It even proudly claims to contain "no dangerous or explosive chemicals". I mean really, where's the fun in that? Here's a picture of the set:
Source: eBay seller 6tomcat
Contributor: Theodore Gray
Acquired: 10 January, 2003
Text Updated: 11 August, 2007
Price: $58/chemistry set
Sample Group: Spinthariscopes