What do sharks and golf balls have in common?

Not much until you start looking at their surfaces. Shark scales are not like ordinary fish scales, they are much smaller and are more like teeth which rise up from the shark’s skin. The scales, called dermal denticles which literally means ‘tiny skin teeth’, all lie in the same direction, from head to tail (unless you’re looking at a basking shark in which case they point in all directions), so if you ever dare to get close enough to a shark to stroke it, it will be smooth in one direction and rough like sand paper in the other.

Close inspection of sharks has revealed that the denticles are like this for a very good reason. Each denticle creates tiny vortices in the water just like the dimples on a golf ball create tiny vortices in the air. And as the dimples on golf balls make them fly further, the sharks’ denticles make them swim more efficiently. They also have the added bonus of allowing the sharks to glide silently through the water giving them an advantage when sneaking up on their prey.

In the same way that researchers are attempting to replicate the sticking ability of gecko feet for human use, a leading swimsuit manufacturer has picked up on the sharks’ secret. They mimicked the sharks’ skin and denticles to make swimsuit fabric with the same properties allowing swimmers to move faster through the water and gain an advantage over their competitors.

Find related websites for hydrodynamics with physics.org

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