In “Getting Shorter With Age,” Katy Bowman reported on some reasoning she did using a paper model of a person (here are her first and last paragraphs):
So, “everyone” gets shorter with age and this phenomenon is usually chalked up to compression over time. It is said that your height decreases because either the discs between your vertebrae have flattened out or, your bone density decreases with age, creating weak bones that can no longer stay upright so they curl forward. This seems to be the general understanding of why we get shorter as we get older. However, things are not always as they appear.
What I’ve presented here isn’t rocket science or genius (the construction paper should have given that away); It’s geometry. But if you aren’t thinking about cellular health in terms of geometry, you’ll miss the more biologically plausible explanation of bone loss, crumbling vertebrae, compressed and bulging discs. Maybe even worse, you’ll be tempted to explain disease in terms of unavoidable gravity, making it seem like something that has nothing to do with your behavior beyond being on the planet. How debilitating is that message?
She did something that we understand and that we could all do, if we just put our minds to it — what she did took some reasoning and some low-tech materials, not some expensive particle accelerator or space shuttle. We should do such things because reasoning — objective, inductive reasoning about cause-effect relationships — makes our lives better, and is part of being independent.