Last Call: This Coin Riddle Forces A Lesson On Newton's Cradle

Show of hands: Who loves The Curiosity Show, an educational Australian kids TV show produced in the '70s and '80s? Just me? Okay, but you're missing out.

The show—clips of which are preserved on YouTube—was a mix of DIY science experiments, magic tricks, and setting off a fish tank full of mouse traps with Ping-Pong balls. Great stuff. It won awards.

Above is a typical Curiosity Show segment in which a simple puzzle involving three coins explains Newton's Cradle, or conservation of momentum. I'll definitely file this one away next time I need to entertain a child for 5 minutes.