The Photo below shows the demonstration used by the University of Texas at Austin.

• Demonstration includes 2 concrete blocks, three boards with nails, sledge hammer & face shield.

• This demonstration requires a faculty volunteer and two demo staff members.

• The faculty member lays down on two nail boards and a third is placed on his chest.

• The face shield is placed over the faculty member's neck.

• Two concrete blocks are carefully balanced onto the to nail board.

• Very soon there after, a demo staff person on a stable stool smashes the blocks dead center with the sledge hammer.

• A second demo staff person should be standing near the front of the table, ready to catch any tumbling block fragments.

Drawing is by courtesy of the University of Minnesota Physics Department web site.