Impressive- and so easy to do!
You start with a yellow block, a solid piece of Plexiglas, and and two wood tubes. After showing both tubes empty, set one tube upright on your table. Place the sheet of Plexiglas on top. Then place the other tube upright on top of the Plexiglas. If you drop anything down through the first tube, whatever you drop will be blocked by the Plexiglas. Nothing can get through to the bottom tube.
OR CAN IT??
Drop the block into the first tube. Your audience can hear it hit the Plexiglas!
But when you lift the top tube- the block is GONE!
Lift off the Plexiglas sheet, and lift up the bottom tube.
THERE IS THE BLOCK!
It has penetrated right through the solid piece of Plexiglas!
How is that possible??
You'll have to get the trick for yourself to find out!