1. Common Characteristics of Fingerprints
Quick Quiz
Can you tell if they match?

2. Fingerprints (and also toe prints) can be used to identify a single individual because they are unique to each person and they do not change over time.
Amazingly, even identical twins have fingerprints that are different from each other, and none of your fingers have the same print as the others! Fingerprints consist of ridges, which are the raised lines, and furrows, which are the valleys between those lines. And it's the pattern of those ridges and furrows that are different for everyone.
Loop fingerprints are the most common type of fingerprint
The patterns of the ridges are what is imprinted on a surface when your finger touches it. If you get fingerprinted the ridges are printed on the paper and can be used to match fingerprints you might leave elsewhere.

3. Characteristics of Fingerprints
While each person's fingerprint is unique, there are three common characteristics that fingerprints consist of. Loops look like thin lassos, where the line goes out and loops back toward itself.
Two types of loops exist: radial loops point toward the thumb (the radius bone) and ulnar loops point toward the pinky (ulna bone). This is the most common type of fingerprint characteristic.

4. Whorls are circular or spiral ridge lines
Whorls are circular or spiral ridge lines. Four kinds of whorl patterns exist.
There are plain whorls, which are your normal circles within circles. Then there are pocket loop whorls, which actually starts as a loop but has a whorl at one end.
There's also the double loop whorl, which is two loops going in opposite directions to make an 'S' shape.
And finally, there is the accidental loop whorl which has no distinct pattern at all and is just an irregularly shaped whorl. Whorls are the second most common type of fingerprint characteristic.

5. The third and final fingerprint characteristic is the arch
The third and final fingerprint characteristic is the arch. These lines look like a hill, starting low at one end, rising in the middle, and then going back down again on the other end.
These wave-like lines come in two types: tented and plain, with tented arches looking more pinched in the middle, much like a tent in the woods. Arches are the least common fingerprint characteristic.
Individualizing Patterns:
So if everyone has just three fingerprint characteristics, what makes each fingerprint unique? It's the way those loops, whorls, and arches align on each finger. Fingerprint analysis looks at unique differences like the distance between different ridges, the heights of arches, the shape of whorls, and the length of loops.

6. You and your sister might both have loops on your thumbs, but if you look very closely, the shape, size, direction, and spacing of those loops is going to be different.
You might not be able to see some of these small but important differences with your own eyes, but fingerprint analysis looks closely enough to do just that.
Tented arches have a higher arch height than plain arches tented arch fingerprint
Fingerprint analysis is especially useful for forensic analysis. Fingerprints that are found at crime scenes can be compared to a database of fingerprints of known individuals to see if there is a match. The first step is to see if the characteristics are the same. If so, then small, sometimes almost imperceptible similarities and differences are compared to identify if there are fingerprints that are the same.

7. Assignment click on link and read article
Answer the following questions:
1. In this story, fingerprints, which have historically been a widely accepted forensic tool, have been subjected to questioning. Explain the argument Patrick Kent, Maryland Public Defender and forensic expert, had about fingerprinting being an art and not a science.
2. Did the judge agree or disagree with Kent? Explain why.
3. How can this decision jeopardize other criminal investigations, current and past?
4. Tom Bush, FBI, had a convincing argument for using fingerprint evidence. Explain his argument.