Fingerprints EQ: What characteristics do Forensic Scientist use to analyzie fingerprints? bsapp.com

Fingerprints as Evidence Visible Fingerprint: Prints left in some medium, like blood, dirt, ink or grease on the finger, that reveals them to the naked eye. Latent Fingerprint: A print made by the deposit of oils and/or perspiration; it is invisible to the naked eye Impressed (Plastic) Fingerprint: An indentation left in a soft pliable surface, such as clay, wax or paint that will take the impression and make it visible to the naked eye.

Principles of Fingerprints First Principle: A fingerprint is an individual characteristic; no two fingers have yet been found to possess identical ridge characteristics. bsapp.com

Principles of Fingerprints Second Principle: A fingerprint will remain unchanged during an individual's lifetime. bsapp.com

Principles of Fingerprints Third Principle: Fingerprints have general ridge patterns that permit them to be systematically classified. bsapp.com

Vocabulary Ridge: Curved line Delta: The point on a ridge at or nearest the point of divergence of two lines Core: The approximate center of the pattern

Deltas & Cores bsapp.com

Three Main Types of Prints Loops Whorls Arches bsapp.com

Loops A loop must have one or more ridges that enter from one side of the print, re-curve, and exit from the same side One Delta & One Core bsapp.com

Whorls Generally rounded or circular in shape Have 1 or more cores and 2 deltas bsapp.com

Arches An arch is formed by ridges entering from one side of the print, rising slightly and exiting on the opposite side. No Deltas & No Cores bsapp.com

In your journal, write the following questions and answer them (1) Do your fingerprints contain loops, whorls or arches? How do you know? (2) Describe the direction of the patterns on your fingerprints (do the ridges curve to the right or left of the card?) (3) Describe the size of each pattern (e.g. how many ridges make up a loop?) (4) Compare your prints to those of other students. Do you see any important differences between male and female fingerprints?

Warm Up Describe the characteristics of this fingerprint and classify it as a loop, arch or whorl. Be sure to use the words “delta” and “core” in your answer.

Fingerprint Challenge For each lettered fingerprint – (1) Circle and label any deltas and cores in the print. If there aren’t any, state “no core, no delta” (2) Classify and label the print as an arch, whorl or loop (3) Match the print to one of the numbered prints in the question mark

Classes of Fingerprints bsapp.com

Arches-No Deltas or Cores An arch is formed by ridges entering from one side of the print, rising slightly and exiting on the opposite side. bsapp.com

Plain Arch The simplest of all fingerprint patterns; a plain arch is formed by ridges entering from one side of the print, rising slightly and exiting on the opposite side bsapp.com

Tented Arch A tented arch rises sharply upward causing the center of the print to look like a tent. By definition, the angle of the lines on a tented arch meets at less than a 90- degree angle. bsapp.com

Loops-One Delta & One Core A loop must have one or more ridges that enter from one side of the print, re-curve, and exit the same side bsapp.com

Ulnar Loops An ulnar loop opens toward the little finger Print from the right hand bsapp.com

Radial Loops A radial loop opens toward the thumb Print from the right hand bsapp.com

Whorls One or more cores At least two deltas bsapp.com

Plain Whorl At least one ridge that makes a complete circuit The ridge may be in the form of a spiral, oval, or any variant of a circle If an imaginary line is drawn between the two deltas contained within the pattern and the line does not touch any of the spiral ridges, then the pattern is a plain whorl. bsapp.com

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

Central Pocket Whorl At least one ridge makes a complete circuit Ridges may be in the form of a spiral, oval, or any variant of a circle If an imaginary line is drawn between the two deltas contained within these two patterns and the line touches any one of the spiral ridges, then the pattern is a central pocket whorl. bsapp.com

Central Pocket Whorl Two Deltas One Core Lacks Symmetry A delta is often observed near the core bsapp.com

Double Loop Whorl A double loop is made up of two loops combined into one fingerprint. bsapp.com

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

Accidental Whorl All other prints bsapp.com

On the back of your fingerprint challenge … For each of your 10 fingerprints, identify at least 3 characteristics and label them as a specific type of arch, loop or whorl using your notes from today. For example L thumb – no deltas, no cores, ridges enter from one side and exit the other and rise sharply in the middle; TENTED ARCH R little – one delta on right side, one core, ridges enter and exit from right side; ULNAR LOOP

Find someone who has… (1) All ulnar loops (2) A tented arch (3) A loop, an arch and a whorl (4) All whorls (5) A double loop whorl Ex. (1) John J has all ulnar loops

Exit Ticket What is the difference between a radial loop and an ulnar loop?