eli5 How come if highly radioactive radium was on watches that the wearers didn’t succumb to radiation poisoning at the wrist?

Question

eli5 How come if highly radioactive radium was on watches that the wearers didn’t succumb to radiation poisoning at the wrist?

In: 186

Answer 1

Radium is an alpha particle emitter. Alphas are big, slow moving particles which are easily stopped by the back of the watch case. The Radium dial painters licked the brushes they used to get a finer point. They had radium inside their bodies, where it could do damage.