Paragraph 2
The
used microscopes to get a close-up
of what happens when a blade cuts a hair. They said a hair made a small
on the blade. This chip got
as it cut more hair. After more
, the blade could not cut cleanly. A
was interested that, "if you cut
very soft, like human hair, with something very
, like steel, the hard material would fail." He said this is "an
engineering
".
