When I was a kid, my stepdad kept a spinthariscope in his sock drawer.* And every once in a while he’d let me take it to bed – because the best way to actually see the radium atoms decaying was in the dark, once your eyes had grown accustomed to the low-light conditions.
But I got to wondering the other day whether letting an eight-year-old sleep with a radioactive toy was, you know, a good idea – never mind holding it up to your eye for hours on end. Granted, this was back when seat belts were optional and second-hand smoke was a feature rather than a bug, but still.
Thankfully, Randall Munroe put my mind at ease with this handy Radiation Dose Chart:
Here’s the full-sized PNG image. It appears I’ll be OK – for the time being, anyway. Oh, and here’s more information on spinthariscopes, including a link to purchase your very own – using thorium instead of radium bromide – for the low, low price of just $49! Sounds like the perfect Father’s Day gift to me.
*No, I don’t know why. I mean, I know why he owned a spinthariscope – because they’re awesome – but his sock drawer?
