pass it along


 
Place 5 pennies in a row on a table top. Use three fingers of the left hand to hold the middle 3 pennies in place. With the right hand slide the rightmost penny away, then quickly back leaving go of it just before it srikes a penny being held in place with a finger. If the 4 stationary pennies are touching each other at the moment of impact, you will see the leftmost penny bounce away as if it had been struck. No matter how tightly you push with the left hand to hold the pennies in place this will happen.