eli5 How come if highly radioactive radium was on watches that the wearers didn’t succumb to radiation poisoning at the wrist?
In: 186
Because there are different kinds of ionizing radiation.
Gamma rays penetrate basically everything and do a ton of damage.
Alpha and Beta are much less penetrative. A sheet of paper or your outermost layer of skin will easily stop the radiation from Alpha-emitters, and Beta isn’t much worse. The radioactive substance mostly has to get directly on or inside you to do damage. Inside you, even alpha and beta rays can do damage and increase cancer risk.
Guess which kind Radium emits?
All of them.
But unless you’re close to a LOT of it, the gamma emissions from just a dab on a watch dial isn’t enough to worry about. The watch casing blocks the alpha and beta. “The dose makes the poison” in this case.
The Radium Girls had *occupational* exposure, though. They worked with Radium paint day in and day out, and ended up ingesting it when they would lick the brushes and similar. Radium ingested can get into your bones and teeth (can be mistaken for Calcium by the body). It’s downhill from there.
Latest Answers