Form and Function - a gecko's tale...

The gecko, that most aesthetic and beautiful of our cold-blooded brethren, is well known for its proficiency at climbing many surfaces. Having watched geckos walking smooth polished marble as if they they were horizontal rather than vertical, I always wondered how they can adhere to such a wide variety of surfaces. I was not the only one to have wondered this and the gecko has finally given us the secret to its abilities - van der Waals forces!:
bq. “Geckos have millions of setae—microscopic hairs on the bottom of their feet. These tiny setae are only as long as two diameters of a human hair. That’s 100 millionth of a meter long. Each seta ends with 1,000 even tinier pads at the tip. These tips, called spatulae, are only 200 billionths of a meter wide—below the wavelength of visible light.”
“‘Intermolecular forces come into play because the gecko foot hairs split and allow a billion spatulae to increase surface density and come into close contact with the surface. This creates a strong adhesive force’, says Autumn.” “A single seta can lift the weight of an ant. A million setae, which could easily fit onto the area of a dime, could lift a 45-pound child. If a gecko used all of its setae at the same time, it could support 280 pounds.”

Posted by Ian at August 28, 2002 12:14 PM | TrackBack §