Forensic Science: Matching Fingerprint Patterns

If you look closely at one of your fingers, you’ll see lines that make a pattern. These lines are slightly raised, which means they’re slightly higher than the surface of your finger. Your skin has natural oil on it. When you touch something, like a glass of milk, you leave a fingerprint pattern of oil on the surface of the object you touched.

Fingerprints are very important evidence for detective work, or for solving crimes, because each person’s fingerprints are unique, as well as each finger’s print is unique. This means that you and your parents all have different fingerprints, and each of your fingers has its own, special print. Fingerprints will never change.

People who study and match fingerprints to people are called forensic scientists. Matching fingerprint patterns is the simplest and best way to identify people, but there are other ways to identify people too, such as by scanning the iris patterns in their eyes. The iris is the colored part of your eye that surrounds the black pupil, or circle, in the middle.

They typically have just a portion, or a part, of a fingerprint. An unknown fingerprint is called a “latent” print, and scientists compare them to “known” fingerprints in police computer files. When comparing prints, scientists look for basic kinds of patterns.

Basic fingerprint patterns have names, like “ulnar loop,” “plain whorl,” and “plain arch.” The ulnar loop looks like long ovals within each other that slope toward your pinkie, while the plain whorl looks like circles inside each other. You start with a circle in the middle and it spirals into more and more circles surrounding