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CONSIDER THIS

CONSIDER THIS. Geckos are small lizards that appear to defy gravity by running up walls and upside down on ceilings as smooth as glass – even on glass itself. How do they do this???. Understanding structure leads to understanding function….

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CONSIDER THIS

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  1. CONSIDER THIS Geckos are small lizards that appear to defy gravity by running up walls and upside down on ceilings as smooth as glass – even on glass itself

  2. How do they do this???

  3. Understanding structure leads to understanding function… Each gecko toe has about two million densely packed, hair-like structures called setae, and each individual seta is as long as twice the diameter of a human hair, Each seta splits into hundreds of even finer tips. This leads to a large surface of contact between the feet of the gecko and any surface. Forces of molecular attraction between the molecules that make up the setae and the molecules that make up walls, ceilings, and other surfaces are large.

  4. Gecko foot hairs, SEMC002/5713 Rights ManagedCaption: Gecko foot hairs. Coloured scanning electron micrograph (SEM) of hairs, or setae, from a gecko's (family Gekkonidae) foot. These hairs enable the gecko to cling to smooth surfaces by taking advantage of weak intermolecular forces, known as Van der Waals forces. Magnification: x9170 when printed 10 centimeters wide.

  5. HOW STRONG? For the gecko, it means that it can hang its entire body from a ceiling by a single toe. Mathematically, if an average gecko used all of its 6.5 million setae at once, it could support over 290 pounds. (To put that in perspective, the average weight of a pro football player is about 250 pounds).

  6. Note: The angle that the setae make contact with the surface determine whether they “stick” or release to allow the gecko to move. http://www.youtube.com/watch?v=JnBkbaFsZOY&feature=related

  7. What are some practical problems for which an understanding of gecko feet could provide a solution??? Brainstorm your own ideas or research and come back with an answer tomorrow.

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