In a sperm’s journey, physics meets biology and art

Sperm keeps on swimmin' swimmin' swimmin'
Sperm keeps on swimmin’ swimmin’ swimmin’. Animation by Brad Purnell

I’ve been working on something really exciting, and it’s finally ready to show you. It’s a video brought out in collaboration with TED-Ed. In it, I explain how the world of a sperm is so fundamentally different from the world of sperm whale. I describe a big idea from fluid mechanics called the Reynolds number, and explain why size matters a  LOT for a swimmer.

It was a blast working with the uber-talented animator Brad Purnell who developed my script into what I think is a brilliant piece of art.

What do some microbes have in common with this lazy cow? Watch the video to find out. Animation by Brad Purnell
Artwork by Brad Purnell
Artwork by Brad Purnell
Artwork by Brad Purnell
Artwork by Brad Purnell

I won’t give away the punch line, so go check out the full lesson here, which comes with puzzles that test your understanding and links to let you dig deeper. Or you can skip all that good stuff and just watch the video below (watch it in HD to get the full effect of Brad’s wonderful animation).

If you want to dig deeper into the physics of fluids and microscopic swimmers, go to the lesson page, click on the side buttons and explore. Have fun!

For more on Brad’s work, here’s his website. Thanks also to Rose Eveleth for invaluable editorial help, and to the editorial and production team and Logan Smalley at TED-Ed for making this possible.