That's why everyone needs to own a set of well made wooden blocks at some point in their life! Blocks let you naturally pick up some really great physics and maths through play, without having to know any algebra.
It's pretty cool to do it with yard sticks. The only problem was that the ones I was using were pretty warped, so they were hard to balance. I'm pretty sure I still got the top one to be all the way over "the void" once.
