My husband sent me this crazy video earlier this morning that I just had to share! When you hang a Slinky by one end and let go of the top, the bottom will not move until the top catches up to it! Check it out!
Why does this work? Here's the complicated explanation: http://large.stanford.edu/courses/2007/ph210/kolkowitz1/
Here's my (simple) explanation: A Slinky is just a big, floppy spring. Springs like to compress to a relaxed state, and will "rebound" to their relaxed state when they are stretched out and then released. Think about stretching a Slinky out on a table and letting both sides go at the same time...they'll meet in the middle, right? Right.
Now stretch that Slinky out by holding one end and letting the other one dangle down so it is being stretched out by gravity. When you let go of the top, gravity is still holding the bottom end in place so it looks like the Slinky is levitating. Watch the video again...Pretty cool, huh?