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 mostly emits alpha radiation. Alpha radiation consists of accelerated helium cores and is the most devastating on our bodies, but also the easiest to shield. The casing of the clock shields *all* of the alpha radiation and I do mean *all* of it. But if you swallow radium, you don’t even have your skin to protect you, so the alpha radiation can hit your organs directly and will kill you in short order.