The words tall and short refer to the vertical extent of something. So we call a person with a greater vertical extent tall and lesser short. But this can be misleading, as there are much greater differences than merely vertical extent between short and tall people. In fact, the fundamental properties of the body vary with height. The square-cube law can explain why.
Take a look at the smaller box in in the figure below. If you double its height while maintaining proportions, length and width also double. Less obvious though is that the volume increases more than the area, twice as much to be exact. This is because 3D volume is proportional to the cube of height while 2D area is merely proportional to the square of height. This is the square-cube law. Galeleo might have been the first to formally recognize this when he stated in his 1638 book, Two New Science, “…the ratio of two volumes is greater than the ratio of their surfaces.”
This is enormously important as so much depends on the ratio of volume to area. For example, weight is proportional to volume while strength is proportional to area. So while strength increases with size, in relation to weight it actually decreases. Another way to say this is that the larger body is absolutely stronger but relatively weaker.
The classic example of this is a comparison between an elephant and an ant. The elephant is stronger, this is most obvious. Where the ant excels, though, is in being able to carry a great many times its own body weight. You see this when ants are carrying food many times their own size back to their queen. Elephants clearly can’t do this. The elephant is absolutely stronger but the ant is relatively stronger. This trend with size is present not just for ants and elephants, but all animals, even humans.
So while tall humans have greater absolute strength, they have lesser relative strength. This is why tall people, like world record holding 6’6″ Behdad Salimi Kordasiabi, can lift more weight but then aren’t as good at push-ups and chin-ups1. Similarly, this can explain why tall people, like 6’5″ Usaine Bolt, may be fast yet make for poor gymnasts due to a lesser ability to accelerate their own bodies.
Beyond forces, the square-cube law has implications for many other aspects of the body, such as thermal properties. Heat generated and contained is a function of volume while heat dissipated is a function of surface area. This means tall people should be better at maintaining body temperature in a cold climate though struggle to cool off in a hot climate or during exertion. This heat transfer relationship also means that taller bodies lose relatively less energy to the external environment, which in turn coincides with a lower metabolic rate in relation to mass. In other words, the taller body is less energy efficient in the absolute sense, yet more so in the relative sense. This has implications for longevity.
This article has assumed that people maintain proportions as they scale. In actuality, however, taller people tend to be relatively skinnier. Furthermore, some tall people arrive at their height via long limbs. These factors can change the relationships discussed above.
- Sekerak RJ, Zimmermann KP. Chin-up strength tests: does stature matter? J Sports Med Phys Fitness. 2008;48(1).
Ha! Take that old gym teacher of mine!
My son the Marine knows this
Please give him my thanks. May he stay safe. (bows) ?
Is it possible to use a custom formula for the square cube law designed for people?
Not quite sure what you’r asking there. Maybe check out the Better BMI Calculator and tweak the exponent: https://tall.life/better-bmi-for-short-and-tall-people/
This article is so ‘understandable’ and so ‘demonstrably true’.
So ‘demonstrably true’!
So, if a man is a “power lifter” with very thick musculature, is 6 ft tall and wts 200lbs…….THEN if his thickness is maintained proportionately, his weight would increase x 8 ?……so if he wt 200 lbs at 6 ft, he’d wt 1600lbs at 12 feet?
…….this formula is being tossed around when people try to estimate the wt of a bigfoot(where 6 ft is judged to be a very young adult)…… I’ve read where people say…..it was about 8ft tall. We measured the limb on the tree that his head touched
I bet he wt 500lbs. His shoulders were about 5 ft across….and I’m thinking, I’ve seen 300 lbs power lifters. Look at Lou Ferigno. No way an 8 ft bigfoot wts only 500 lbs. And does this sq/cu theory increase EXPONENTIALLY if ur guesdtimating the wt of something
18 ft tall ? And what are those exponents?…..thank you
Exponent of 3 means isometric (same in all directions) scaling, where if height doubles so do width and length so 8 times the volume (2 x 2 x 2 = 8) and thereby 8 times the mass. Exponent of 2 means less than isometric, so kinda like only the width but not the thickness scale, so mass increases by factor of 4. In reality, it is somewhere in between for how humans scale.
The square cube law does not work with static objects. Let’s take a large baby 1.5 feet tall and 30 lbs. The square cube law demands when the height is doubled the volume/weight = x8. That block on the left fits exactly 8 times in the large block.
So the square cube law as the height doubles to 3 feet tall the weight is multiplied by x8, 30 x 8 = 240 lbs. Thats a child 3 feet tall and the weight of the WWE wrestler EDGE. Let’s double the height to 6 feet X8 the weight again: (240 x 8 = 1,920 lbs)
One thousand nine hundred and twenty lbs.
If this was done with 30 lbs of concrete (30lbs x 8 x 8 =1920lbs) It would work perfectly.
But not with biological organisms. The square cube law does not predict the skull will add less than half its size and almost stop at age 15. The square cube law does not predict that the hips down will stretch out to become half the height. The square cube law does not predict that the body will grow up and not out equally, The square cube law does not predict that the head to body ratio will go from 1 to 3 as a baby to 1 of 8. The square cube law is a law of physics and it does not work with static objects.
Obviously if the square cube law is incapable of predicting the outcome at 6 feet how does it determine 8 feet 10 feet or 12 feet humans with any accuracy?
If you want to see evidence of human giants in every state.