Mathemagic or Simple Physics?

Can you balance 30-plus nails on a single nail-head? Mrs. Richmann`s sixth grade math students can. \"Students discovered the secret of balance in their math classes,\" reports Mrs. Richmann. \"Working in teams, they were given a block of wood with one nail in it. The problem posed to them was to find a way to balance ten large nails on the single nail-head. \"After many attempts at starting to lay nails across the head, it soon became apparent that more than one nail would just roll off and drop. Relating the idea of balance to a tightrope walker, students could visualize the aerialist carrying a long flexible pole with ends that bend down. This picture led to a discussion of a basic property of physics - a low center of gravity enables balance to occur on a very small surface. \"As students persisted in unraveling this enigma, they began to formulate structures on tabletops instead of nail-heads. Within a few minutes, eight nails were laid in alternating directions along a single nail. With one nail as a base and four nails on each side, the tenth nail placed atop the structure provided the stability to pick up the nail configuration and gingerly set it on the nail-head protruding from the wood block. The students could hardly contain their excitement as they achieved a feat that initially seemed impossible! \"Teams continued to explore their skills by adding nails to the original ten. The record is a whopping thirty seven! Oh the miracles of science and math ...\"