This went up on my social media profiles, but I'll put it up here too:

There are 10 piles of gold plated balls. Each pile has 10 balls. Each pile is visually identical to the other.

9 of the piles have balls that are gold plated lead, which are therefore worthless and weigh 10lbs/ball.

1 of the piles has balls that are solid gold, which are therefore worth a lot and weigh 9 lbs/ball.

Your objective is to obtain the pile of solid gold balls. However, your only diagnostic tool is a weigh scale, and it will break after *one* use. Strangely, the weigh scale is of the size and capacity that you can weigh any number of balls from any number of piles.

What's the solution?

Also consider whether or not you want to post the solution and therefore spoil it to someone who's thinking about it.