Below Is A Cartoon,

depicting a child's toy,

the cartoon is the latest xkcd comic by Randall Munroe, but here is the thing, this radioactive toy could be bought in the 1940s, it happened like this, Sir William Crookes invented it by accident during his nuclear experiments in 1903, He spilled a tiny amount of radium bromide (a radioactive salt) onto a thin screen of zinc sulfide. Since radium bromide was a very expensive material, he carefully picked up every speck, using a magnifying glass to see them. He noticed flashes of light, produced by the radium bromide throwing off alpha particles. This was a pretty neat discovery, so Crookes fashioned an enclosed device for observing the effect. That's how the spinthariscope was born, as a scientific instrument, the spinthariscope soon became obsolete, but it was still impressive to non-physicists and kids. In 1947, you could order one from the back of a cereal box, in the 1950s, a small spinthariscope was included in the Chemcraft Atomic Energy Lab for children! similar I guess to the Gilbert's one we featured here,

and here is the one you could buy all of those years ago, photograph credit Theodore Gray, naturally these radioactive 'toys' that allow you to see atoms and mini nuclear explosions can not be bought today, or can they?