Gecko feet act like anti-grav­ity boots

World of Animals - - Defying Gravity -

“It’s pos­si­ble that when a gecko’s

foot touches the wall the two sur­faces ex­change elec­tric charges”

A gecko’s toes are cov­ered in tiny hairs that stick to sheer sur­faces. Each hair splin­ters off into hun­dreds of smaller bris­tles that are thought to ac­ti­vate van der Waals forces be­tween the foot and the sur­face below it. These are dis­tance-de­pen­dent in­ter­ac­tions be­tween mol­e­cules that are rel­a­tively weak, but the great num­ber of spat­u­lashaped hair ends get close enough to the con­tours on the seem­ingly flat sur­face to al­low the lizard to stick.

There are other the­o­ries that could ex­plain this phe­nom­e­non. It’s pos­si­ble that when the foot touches the wall the two sur­faces ex­change elec­tric charges. One be­comes pos­i­tively charged while the other is neg­a­tive, re­sult­ing in at­trac­tion. Lab­o­ra­tory tests that coun­ter­act van der Waals forces seem to have no ef­fect on the gecko’s abil­ity to ad­here to a smooth wall. How­ever, it may be pos­si­ble that van der Waals forces come into play on rougher sur­faces.

right The only sur­face gecko feet can’t at­tach to is non-stick Te­flon, which coats the pots and pans in your kitchen

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