1. Warm Up
Objective: Scientists will describe fingerprints and their use by analyzing their own fingerprints.
What is the topic?
What will you be doing?
Why is this important?
How will you know if you have done well?

2. Warm Up
Objective: Scientists will describe fingerprints and their use by analyzing their own fingerprints.
What is the topic? Fingerprints and their use
What will you be doing? Analyzing fingerprints
Why is this important? Evidence for convictions; future career choice
How will you know if you have done well? Able to describe fingerprints and use; analyzed fingerprint

3. History of Fingerprints
Ancient Babylon (1750 B.C.)
Fingerprints pressed into clay tablets marked contracts.
Third century B.C. China
Contract documents showing fingerprints
1788, Johann Mayer
Noted that the arrangement of skin ridges is never duplicated in two persons.
The first scientist to recognize this fact.

4. What Are Fingerprints?
All fingers, toes, feet, and palms are covered in small ridges.
These ridges are arranged in connected units called dermal, or friction, ridges.
Ridges help us get or keep our grip on objects.
Natural secretions plus dirt on these surfaces leave behind an impression (a print) on those objects with which we come in contact.

5. PRINCIPLES OF FINGERPRINTS
There are 3 fundamental principles:
1) Individual characteristic
No two people have been found with the exact same fingerprint pattern.
2) Pattern will remain unchanged for the life of an individual
The print itself may change due to permanent scars and skin diseases.
3) General characteristic ridge patterns that allow them to be systematically identified.

6. Fingerprint Characteristics
Forensic examiners look for the presence of a core (the center of a whorl or loop) and deltas (triangular regions near a loop).
Delta

7. Types of Fingerprints There are 3 general fingerprint distinctions:
Arches
Loops
Whorls

8. 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.
2 types: plain arch & tented arch
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.

9. Arches

10. Radius
Ulna
Left Hand
Loops
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.
Types
Radial—opens toward the thumb
Ulnar—opens toward the “pinky”
L – Ulnar Loop
R - Radial Loop
L – Radial Loop
R - Ulnar Loop

11. Loops

12. Whorl
A plain or central pocket whorl has at least one ridge that makes a complete circuit.
A double loop is made of two loops.
An accidental is a pattern not covered by other categories.
Whorls have at least two deltas and a core.
4 Types
Plain
Central Pocket
Double Loop
Accidental

13. Plain Whorl Two Deltas One Core Displays a degree of symmetry
bsapp.com

14. Central Pocket Loop Two Deltas One Core Lacks Symmetry
A delta is often observed near the core

15. Whorls – Part 2 Accidental Whorl Double Loop Whorl
Double loop whorls are made up of any two loops combined into one print.
Delta
Accidental Whorl
Accidental whorls contain two or more patterns (not including the plain arch), or does not clearly fall under any of the other categories. 15

16. Double Loop
Two Deltas
Two Cores
Appears to have an “S” in the print

17. Accidental
All other prints
bsapp.com

18. Fingerprint Balloon
Blow up your balloon about halfway and twist the end to keep the air from coming out. Do NOT tie it off yet!
Use an ink pad to make a print with all of your fingers and label each one with a permanent marker. Write your name on the balloon.
Blow up the balloon to full size and tie the end
Let it dry!
Identify the ridge pattern for each finger and thmb
Using the ridge characteristics paper, identify them on your balloon by circling and labeling. Try to find as many as you can!

23. Analysis What type of fingerprints do you have?
How do you know? (What minutiae did you use?)
How can fingerprinting be useful?