You have the ability to pick up small objects because you have a very special thumb. It can move in many directions. We call this type of thumb an oposable thumb. To aide in helping you pick things up, nature has put small grippers in your fingers. The grippers have high and low points on them. The grippers form patterns and designs. We call these designs
Close up of a finger tip showing
The HIGH points are called
hills, while the LOW points
are called valleys
The edges of the penny are higher
Your fingerprint is like this too.
The hills or ridges stick up and get
ink on them. The hills and ridges
leave a mark on paper as does the
outer edge of a penny. The white
lines on a fingerprint are the
valleys or spaces between the
hills. These areas never got ink on
them because they were lower
and never reached the ink pad.
1) Define these terms (Look in a dictionary)
2) Why does ink not get into the valleys on your finger?
3) How do the prints on your fingers help you?