Airdate: Jan 14, 2010
Scientist: Bob Full
Kids' Science Challenge: Biomimicry - Toe Hair
Hairy toesREALLY hairy toesare essential to a gecko's wall-climbing ability.
JM: Hairy toes and millions of split ends could be a recipe for embarrassment for you or me. But for a gecko, they're extremely useful tools. I'm Jim Metzner, and this is the Pulse of the Planet. A gecko's ability to climb vertically on a piece of glass has to do with its toe hair, and lots of it. University of California biologist Bob Full explains.
BF: Here's the tokay gecko, and if we look at its feet, what we see is that they have these leaf-like structures. And if we look at one toe, we see these leaves, and notice they're not solid. There are little structures in there and we can zoom in on those. Look at one of the leaves, and what we see is that it looks like a rug. You can see all the hairs in the rug when you increase it 270 times. And then, if we look more closely 900 times you can see one of these hairs, and there's something going on at the end of the hair. It's not a solid piece either. And here's the secret of how geckos stick to things. They have the worst case of split ends possible. And a gecko has about a billion of these little nano-size split ends. That's eight-millionths of an inch big really small. There's the gecko foot. There's one of the gecko hairs. Gecko hairs are small, but that's not what sticks. If you look at the end, those are the tiny, little branches that stick to the other surface.
JM: Millions of microscopic hairs give a gecko's toe incredible surface area, which attracts it on a molecular level to vertical surfaces.
Bob Full is one of the participating scientists in this year's Kids' Science Challenge, our free nationwide competition for third to sixth graders, made possible by the National Science Foundation. Can you think up a bio-inspired invention? Then check out kidsciencechallenge.com. I'm Jim Metzner.