The physics of scale has a profound effect on locomotion. The way we move through the world seems so normal, but is very different from what a single-cell organism has to deal with. The title comparison of this TED-Ed presentation comes from the fact that a sperm is a single cell that must move, but cannot do it the same way larger organisms like a whale moves around. Aatish Bhatia gives us the short version, with animation by Brad Purnell. You'll find a more in-depth explanation at Bhatia's website. Link -via Viral Viral Videos