Human hair is about 50 times softer than a razor blade, which is made using heat-hardened stainless steel and often reinforced with diamond-like carbon. Yet, a few wisps of hair are powerful enough to dull a blade's sharpness within a few weeks of use. To understand how this impressive feat occurs, a team of researchers from the Massachusetts Institute of Technology (MIT) decided to take a closer look at what happens when the sharp edge of a blade slices through human hair.