IntroductionSo who was he?
What are Van der
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err... Lizards?
Yes, that's right, one of the great mysteries of the animal kingdom has recently been solved - that of the gecko, pictured above. These small lizards are able to walk on glass, and even upside-down on ceilings. This puzzle was solved last year when a research team proved that the forces adhering the gecko to its surface were in fact just Van der Waals forces, caused by the huge surface area of its feet.
The
feet, they discovered, are covered in very many tiny hairs, or setae, which are
the length of two diameters of human hair. Each hair has 1000 pads at its
tip - spatulae - which are 200 nm wide. A single spatula is able to
support an ant, all without using any adhesive. This brings the
total sticking power of the four feet of a gecko to
around about 20 stone. That's over two stone heavier than Mike Tyson. The research team are now looking into using their new findings to produce sticky tape which works without adhesive, does not leave any residue and is entirely reusable. So far they have produced a couple of centimetres square of tape, made by punching holes into silicon rubber and polystyrene resin using an atomic force microscope. The tape is difficult to produce at the moment, and is only about as effective as unbumped rubber, but it is strong enough to support small weights, such as the action figure shown.
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