A Standing Problem

Scaling: a Weighty IssueIssues

There is an age-old physical dilemma that plagues structural engineers and scale modeling enthusiasts alike: the problem of strength to weight ratios.ratio.  As a kid I always wondering why a plastic scale model of an airplane wasis hopelessly unable to mimic, even onto a smaller scale, the aerodynamic performance of the real aircraft.  Conversely, a toy or plastic model of a car can be dropped and makeexposed to scale-speed impacts with similarwithout vehicles withoutreceiving a dent.  Imagine a highway speedcar impactwreck where vehicles bounce without damage!  Similarly, a model bridge gluedmade from popsicle sticks could not be directly scaledscale up to a size capable of supporting actual road traffic with out significant changes in materials, dimensions, and joints.traffic.

WeightStrength to weight ratio (or Specific Strength) can have surprising real-world implications.  Weight is related to volume (third order) while strength ratiosis arerelated oftento surprising.area of material cross-section (second order).  ForAs solida (non-hollow)real structures,life example, the weightstrength to strengthweight ratio of Balsa wood is greater than any metallic alloy. ( This is great for building model rocketrockets, hobbyistsyet takeit's advantage of this), but itsclearly not possible to build an aircraft or rocket capable of carrying humans entirely from Balsa.  LookingAnts atcan structures in animals, insects can carry proportionatelyup massiveto loads20x ontheir surprisinglybody thin legsweight, and small lizards and frogs are able tocan climb window panes,panes supported only by the attraction force withof the glass.

Dino-Sized Concerns