The Cutting-Edge Physics of a Crumpled Paper Ball
“Crush a piece of typing paper into the size of a golf ball, and suddenly it becomes a very stiff object. The thing to realize is that it’s 90 percent air, and it’s not that you designed architectural motifs to make it stiff. It did it itself,” said physicist Narayan Menon of the University of Massachusetts Amherst. “It became a rigid object. This is what we are trying to figure out: What is the architecture inside that creates this stiffness?”
Take an 8.5×11″ sheet of paper and an 8.5×11″ sheet of aluminum foil. Crumple each to the same exerted prressure and compare final sizes. Interesting. Consider the density of the Eiffel Tower, mass/volume, and compare to that of an aerogel. Structure trumps composition.
http://www.physicstoday.org/daily_edition/physics_update/building_ultralight_lattices
A robust structure must also resist failure due to accumulating introduced defects.