Research: fingerprints are unlikely to increase ‘grip’ to our hands!
May 31, 2009
In may 2009 Dr Roland Ennos and his team at The University of Manchester presented fingerprints findings with a surprizing outcome. Fingerprints do not help primates grip, as previously thought. Instead, a fingerprint actually reduces the friction needed to hold onto flat surfaces.
Dr Ennos disproved the long-held assumption that fingerprints help primates to grip with a simple machine, three strips of perspex and the right hand of Masters student Peter Warman. They tested the student’s grip on every finger + thumb at three different widths of perspex as the machine pulled the perspex strips down via a weight in a plastic cup. The researchers also tested grip at three different angles by bending both the fingers + the thumb. This wide range of testing conditions allowed them to separate pressing force from the contact area and overcome any confounding variables.
The results indicate that fingertips act more like rubbers than hard solids; their friction coeficient fell at higher normal forces and friction was higher when fingers were held flatter against wider sheets and hence when contact area was greater.
WHY DO WE HAVE FINGERPRINTS?
“The experiment was so simple, this discovery could have been made 100 years ago; but scientists make assumptions and tend to look at complicated things instead.
My preferred theory is that they allow the skin to deform and thus stop blistering. That is why we get blisters on the smooth parts of our hands and feet and not the ridged areas: our fingerpads, palms and soles.”
SUGGESTIONS FOR LEARNING MORE ABOUT FINGERPRINTS: