“On Being The Right Size”, 1927-03-27 (; backlinks; similar):
[Popular science discussion of scaling laws by biologist: why does a short fall not faze a mouse or insect but injures a man and makes a horse go splash, and why are giants impossible? Because the strength of bodily parts increases less than total volume or weight, and they become weaker and more fragile the bigger they are. Other examples include surface tension, blood pumping, oxygen respiration, flying, warm-bloodedness vs volume, eye acuity, brain size—and perhaps human organizations like governments and businesses?]
Let us take the most obvious of possible cases, and consider a giant man sixty feet high—about the height of Giant Pope and Giant Pagan in the illustrated Pilgrim’s Progress of my childhood. These monsters were not only ten times as high as Christian, but ten times as wide and ten times as thick, so that their total weight was a thousand times his, or about eighty to ninety tons. Unfortunately the cross-sections of their bones were only a hundred times those of Christian, so that every square inch of giant bone had to support ten times the weight borne by a square inch of human bone. As the human thigh-bone breaks under about ten times the human weight, Pope and Pagan would have broken their thighs every time they took a step. This was doubtless why they were sitting down in the picture I remember. But it lessens one’s respect for Christian and Jack the Giant Killer.
View PDF: