...Oh, yes, and while I'm at it...The Army used to paint things with radium to make them visible at night.This is because radium - a RADIOACTIVE SUBSTANCE - emits visible light.You fail again. Abusive comment hidden. (Show it anyway.)
The Army used to paint things with radium to make them visible at night.
This is because radium - a RADIOACTIVE SUBSTANCE - emits visible light.
You fail again.