1F20.10 - Block and String
Demonstrate inertia of a large block with a surprising outcome.
A heavy block is hung by a relatively light piece of string or thread and a heavier piece of string is fastened to the bottom.
If the bottom string is given a quick snap it will break instead of the thin top string. To provide a "quicker snap", the bottom string is attached to a piece of wood that is easily held in your hand.