Your sense of touch might be better than you think. A study at the University of Delaware showed that human fingertips can feel tiny changes in the composition of materials—down to the atom, the smallest unit of matter.

To test the sensitivity of fingertips, a team of scientists created two different monolayers, just one molecule thick. One monolayer contained carbon (C) atoms. The other contained larger nitrogen (N)-based molecules called amines. Both of these nearly invisible, ultra-thin materials were layered over identical smooth surfaces. Volunteers were able to sense slight differences in friction when their fingers rubbed against the two layers. Compared to the carbon monolayer, the molecules in the amine monolayer were arranged in a more ordered pattern, making it feel slightly smoother to the touch.