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Scientists Discover What Makes Geckos Stick
Scratch-O-Matic writes "This story at CNN explains how gecko feet are sticky due to an electro-mechanical phenomenon rather than a chemical glue, as had been previously assumed. The gecko is one of just a few animals capable of climbing vertical and beyond-vertical surfaces that are smooth and dry. Researchers have discovered that the secret to the adhesion lies in millions of tiny hairs called
'setae.' Each hair is the width of two human hairs, and contains about 1000 little pads at the end. The pads are so tiny that they actually cling to the surface at the molecular level, due to van der Waal forces. A gecko using all of its setae and pads at the same time could support 280 pounds. Seems to me that his should be easily replicated in the coming age of nanotechnology." Other readers point to the AP story, as carried by Yahoo! and also playing at Salon.
This study sponsored by the "The Association For Producing Low Cost Sticky Notes".
I'd imagine we could put the sticky note out of business if we could get markers to write on geckos with......
Very timely... Read about this in Scientific American over a year ago! Takes awhile for scientific knowledge to disseminate I guess.....
All I need to climb walls are hairy palms? I'll get right on that!
Karma: Marginal (mostly due to the border around the website)
One my profs works on geckos, he was telling me that even dead geckos stick to walls. Fun for the whole family!
This has been known about since 2000 at least; we used to have endless discussions over the fact that geckos have the impressive ability to stick to ceilings in a vacuum, discussions on topics such as:
a) how did they find out the details? Did it involve a research assistant, a glass container, a vacuum pump and a large supply of geckos?
b) How did Geckos evolve this feature? Are geckos secretly descended from a life form that can stick to the outside of space craft?
c) Alternatively, does this prove that creatures are designed rather than evolved, and the design process is a bit more like the PhD process than anything else; some little godling spends millenia working on geckos in order to submit some paper 'An alternative mechanism for achieving stickiness in creatures' only to have it discredited by a board of professors who have always used suction and thats how they believe all creatures should stick.
The 280 lb gecko they used for the experiment simply asked for more donuts when questioned about the validity of the scientists claims.
--It's Pimptastic!--
Why is everyone reporting this like it was just discovered?
BBC covered it over two years ago.
Probably what happened is that a major news service hired a new reporter who heard something cool and decided to write about it. But he didn't know it was old news. Like little robots, every other newspaper in the country picked up the story and published it This kind of thing happens with just about every story. It's almost like we have one giant national newspaper.
If tits were wings it'd be flying around.
I just love my Tokay Gecko. It's as mean as it can be. The Tokay is the pit-bull of geckos.
I had a bad roach problem. I did'nt want to use pesticides in my home so a friend recommended a Tokay. I was open to all options so I bought a Tokay and let it loose in my home.
The roaches were gone in two days. It was lovely. I would wake up at night turn the lights on and see my little guy on a wall somewhere.
It did such a good job eating roaches that it eventually ran out of food. I had to catch it (not easy since it put up a good fight) and put in a terrarium where it happily eats crickets.
I love my little guy.
Here is a picture I took of my little buddy.
They figured how Gecko's stick to glass surfaces, but they never figured out how they let go! Another fifty years of research to figure that out...sheesh!
If memory serves it's van der Waals.
It's an ultra-short range stickiness that applies to just about any material.
Anybody with a physics degree will be horrified by this explanation, but conceptually imagine two neutral atoms, really close. Imagine that atom A momentarily has more of its electron cloud on the side away from atom B. Then atom A will look slightly positive to atom B. A positive charge attracts electrons, so atom B's electron cloud gets redistributed toward atom A. Atom B now looks slightly negative, keeping A's electrons (better, A's electron probability distribution (better yet, we should be talking complex amplitudes and energy values)) on the far side from B.
Corrections and clarifications to the above are entirely welcome.
Lab equipment for studying herpi-podiatry: $68,000
Salaries for scientists and lab assistants: $230,000
Ticket to "Spiderman": $8.50
The fact that this was discovered only after getting the idea from the Spiderman movie: priceless.
c-hack.com |
For all those wondering why this subject suddenly returned to the limelight, it's due to a paper realased today in the Proceedings of the National Academy of Sciences (or pnas for those in the know).
Here's a link to the Autumn, et al. article, entitled "Evidence for van der Waals adhesion in gecko setae".
If the forces in use are only Van der Waals, and these forces are present everywhere, what makes geckos, or rather their little hairs, special so that their molecules can stick to walls and mine can't?
:).
If I understand correctly, it's because the hairs and pads are arranged so that the sticky pads can follow surface curvature down to a near-molecular level.
Most surfaces, even ones that are polished smooth, are very rough on a small scale. This roughness is actually fractal; it's not just one level of coarseness (like sandpaper), it's coarseness on many scales. Match it on one scale, and the next step finer still keeps most of the surface away from you.
So, if you put your finger on a surface, you're still not touching much of the surface, even if you press quite hard. This limits the amount of van der Waals adhesion you can get (as the effect happens over molecular distances).
A thin film of water or oil can fill the crevases and make the bonding much stronger, if you want to try sticking your fingers to things. Don't try hanging off the ceiling, though
Disclaimer: This explanation could be completely wrong. It's just the most plausible one I can think of.