6th May 2020 - Finger Sensitivity

When ever a woodturner picks up a finished piece the first thing is to run a finger across the surface, particularly at a centre point to see if any ridges or dips have been left behind. We just can’t help it but have you ever wondered just how small a bump our fingers can feel?

The following extract from a scientific paper throws some light on it. 

Fingers can detect nano-scale wrinkles even on a seemingly smooth surface

In a ground-breaking study at the KTH Royal Institute of Technology in Stockholm, Swedish scientists have shown that people can detect nano-scale wrinkles while running their fingers upon a seemingly smooth surface. Mark Rutland, Professor of Surface Chemistry, says that the human finger can discriminate between surfaces patterned with ridges as small as 13 nanometres in amplitude and non-patterned surfaces.

"This means that, if your finger was the size of the Earth, you could feel the difference between houses 

from cars," Rutland says. "That is one of the most enjoyable aspects of this research. We discovered that a human being can feel a bump corresponding to the size of a very large molecule."

Courtesy of www.ScienceDaily.com

Ted Higgs

6 May 2020