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A Standing Problem

Scaling: Weighty Issues

There is an age-old physical dilemma that plagues structural engineers and scale modeling enthusiasts alike: strength to weight ratio.  As a kid I always wondering why a plastic scale model of an airplane is hopelessly unable to mimic, even to a smaller scale, aerodynamic performance of the real aircraft.  Conversely, a plastic model of a car can be dropped and exposed to scale-speed impacts with without receiving a dent.  Imagine a highway car wreck where vehicles bounce without damage!  Similarly, a model bridge made from popsicle sticks could not directly scale up to a size capable of supporting actual road traffic.

Strength to weight ratio (or Specific Strength) can have surprising real-world implications.  Weight is related to volume (third order) while strength is related to area of material cross-section (second order).  As a real life example, the strength to weight ratio of Balsa wood is greater than any metallic alloy.  This is great for building model rockets, yet it's clearly not possible to build an aircraft or rocket capable of carrying humans from Balsa.  Ants can can carry up to 20x their body weight, and small lizards and frogs can climb window panes supported only by the attraction force of the glass.

Dino-Sized Concerns