1. 6th Grade Forensic Science
Fingerprints
6th Grade Forensic Science
T. Trimpe

2. Fingerprint Principles
According to criminal investigators, fingerprints follow 3 fundamental principles:
A fingerprint is an individual characteristic; no two people have been found with the exact same fingerprint pattern.
A fingerprint pattern will remain unchanged for the life of an individual; however, the print itself may change due to permanent scars and skin diseases.
Fingerprints have general characteristic ridge patterns that allow them to be systematically identified.

3. Fingerprint Classes
There are 3 specific classes for all fingerprints based
upon their visual pattern: arches, loops, and whorls.
Each group is divided into smaller groups as seen in the lists below.
Arch
Plain arch
Tented arch
Loop
Radial Loop
Ulnar loop
Whorl
Plain whorl
Central pocket whorl
Double loop whorl
Accidentical

4. 60% of people have loops, 35% have whorls,
Interesting Info
Fingerprint Factoid:
60% of people have loops, 35% have whorls,
and 5% have arches
Did you know?
Dactyloscopy is the study of fingerprint identification. Police investigators are experts in collecting “dactylograms”, otherwise known as fingerprints.
ADD TO NOTES

5. Arches
Arches are the simplest type of fingerprints that are formed by ridges that enter on one side of the print and exit on the other. No deltas are present (deltas = little triangles off to the side)
Tented Arches
Similar to the plain arch,
but has a spike in the center.
Spike or “tent”
Plain Arch
Ridges enter on one side and
exit on the other side.

6. Loops
Radius
Ulna
Left Hand
Loops must have one delta and one or more ridges that enter and leave on the same side. These patterns are named for their positions related to the radius and ulna bones, i.e. the bone the loop opening is facing towards.
L – Radial Loop
R - Ulnar Loop
L – Ulnar Loop
R - Radial Loop
Delta
X-Ray Imagine:

7. Whorls
Whorls have at least one ridge that makes (or tends to make) a complete circle. The middle part looks like a bullseye, and they also have at least two deltas.
Central Pocket Whorl
Plain Whorl
There are 4 types of whorls.
1. A mostly centered bulls-eye is a Plain Whorl.
2. If the bulls-eye loops off to the side, then it is a Central Pocket Whorl

8. Whorls – Part 2 Double Loop Whorl
3. A double loop whorl looks like a Yin-Yang sign. They are made up of any two loops combined into one print
Delta
Accidental Whorl
4. Accidental whorls are fingerprints that do not clearly fall under any of the other categories.

9. Identify each fingerprint pattern.? A B
Right Hand
Left Hand
Answer Key: A - Plain Whorl, B – Double Loop Whorl, C – Radial Loop, D – Tented Arch, E – Plain Arch C
Right Hand E D
Right Hand
Left Hand

10. It’s time to make some prints!
Put the tape up and down to avoid Partial Prints
GOOD PRINTs Get as much of the top part of your finger as possible!

11. Directions
1st – scribble a dark blotch of graphite (pencil lead) onto a piece of scratch paper. Make sure that it is completely filled in!
2nd – Rub your finger in the graphite blotch, until the entire fingertip is darkened
3rd – Take a 1 inch piece of scotch tape, and stick it to your finger, as shown in the picture
4th –Carefully peel off the tape & stick it to the correct spot on Your Fingerprints sheet