ABSTRACT
If one examines the trail of a gecko one sees it is completely dry; the gecko does not use any kind of “glue” or suction pads for climbing walls and ceilings.
The question is: What is the force that allows the gecko to walk on walls and ceilings without falling down? Since no chemicals or fluids are involved, the force must be due to the physical interaction of the gecko’s feet with the atoms and molecules of the wall. As discussed in Chapter 5, a solid material consists of bonded atoms and molecules that have a separation of about 0:1-10 nm (nanometer), where 1 nm = 109 m.
