Safety standards were different in 1947. My older brother had the chemistry set pictured and I have to tell you that the uranium samples were not fake at all. They lit up the phosphors in the radiation screen. A later set had an alpha emitter in a small tube with a lens. When your eyes were adapted to the dark the alpha particles caused tiny flashes of light that were visible. Nowadays even vinegar and baking soda toys come with a detailed safety guide. Probably better for kids, but it was a very different time to grow up.